N79E352/R Preliminary Datasheet by Nuvoton Technology Corporation of America

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Preliminary N79E352/N79E352R Data Sheet
8-BIT MICROCONTROLLER
- 1 -
Table of Contents-
1. GENERAL DESCRIPTION .......................................................................................................... 4
2. FEATURES ................................................................................................................................. 5
3. PARTS INFORMATION LIST ..................................................................................................... 6
3.1 Lead Free (RoHS) Parts information list ......................................................................... 6
4. PIN CONFIGURATIONS ............................................................................................................. 7
5. PIN DESCRIPTIONS .................................................................................................................. 9
6. FUNCTIONAL DESCRIPTION .................................................................................................. 11
6.1 On-Chip Flash EPROM ................................................................................................. 11
6.2 I/O Ports ........................................................................................................................ 11
6.3 Serial I/O ....................................................................................................................... 11
6.4 Timers ........................................................................................................................... 11
6.5 Interrupts ....................................................................................................................... 11
6.6 Data Pointers ................................................................................................................ 11
6.7 Architecture ................................................................................................................... 11
6.8 Power Management ...................................................................................................... 12
7. MEMORY ORGANIZATION ...................................................................................................... 13
7.1 Program Memory (on-chip Flash) ................................................................................. 13
7.2 Data Memory ................................................................................................................. 14
7.3 Scratch-pad RAM and Register Map ............................................................................ 14
8. SPECIAL FUNCTION REGISTERS .......................................................................................... 17
8.1 SFR Location Table ...................................................................................................... 17
8.2 SFR Detail Bit Descriptions ........................................................................................... 21
9. INSTRUCTION .......................................................................................................................... 51
9.1 Instruction Timing .......................................................................................................... 58
9.2 MOVX Instruction .......................................................................................................... 62
9.3 External Data Memory Access Timing .......................................................................... 63
9.4 Wait State Control Signal .............................................................................................. 66
10. POWER MANAGEMENT .......................................................................................................... 67
10.1 Idle Mode ...................................................................................................................... 67
10.2 Economy Mode ............................................................................................................. 67
10.3 Power Down Mode ........................................................................................................ 68
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Preliminary N79E352/N79E352R Data Sheet
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11. RESET CONDITIONS ............................................................................................................... 69
11.1 Sources of reset ............................................................................................................ 69
11.2 Reset State ................................................................................................................... 69
12. PROGRAMMABLE TIMERS/COUNTERS ................................................................................ 71
12.1 Timer/Counters 0 & 1 .................................................................................................... 71
12.2 Time-base Selection ..................................................................................................... 71
12.3 Timer/Counter 2 ............................................................................................................ 74
13. NVM MEMORY ......................................................................................................................... 78
13.1 Operation ...................................................................................................................... 78
14. WATCHDOG TIMER................................................................................................................. 80
15. UART SERIAL PORT ................................................................................................................ 82
15.1 Mode 0 .......................................................................................................................... 82
15.2 Mode 1 .......................................................................................................................... 83
15.3 Mode 2 .......................................................................................................................... 84
15.4 Mode 3 .......................................................................................................................... 87
15.5 Framing Error Detection ................................................................................................ 88
15.6 Multiprocessor Communications ................................................................................... 88
16. I2C SERIAL PORT .................................................................................................................... 90
16.1 I2C Bus ......................................................................................................................... 90
16.2 The I2C Control Registers: ........................................................................................... 91
16.3 Modes of Operation ...................................................................................................... 93
16.4 Data Transfer Flow in Five Operating Modes ............................................................... 94
17. TIMED ACCESS PROTECTION ............................................................................................. 100
18. INTERRUPTS ......................................................................................................................... 102
18.1 Interrupt Sources ........................................................................................................ 102
18.2 Priority Level Structure ................................................................................................ 103
18.3 Interrupt Response Time ............................................................................................ 105
18.4 Interrupt Inputs ............................................................................................................ 105
19. KEYBOARD FUNCTION ......................................................................................................... 106
20. INPUT CAPTURE ................................................................................................................... 108
21. PULSE WIDTH MODULATED OUTPUTS (PWM) ................................................................. 110
22. I/O PORT ................................................................................................................................. 111
22.1 Quasi-Bidirectional Output Configuration .................................................................... 111
22.2 Open Drain Output Configuration ............................................................................... 112
22.3 Push-Pull Output Configuration................................................................................... 113
22.4 Input Only Mode .......................................................................................................... 113
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Preliminary N79E352/N79E352R Data Sheet
Publication Release Date: Jul, 29, 2009
- 3 - Revision A06
23. OSCILLATOR .......................................................................................................................... 115
23.1 On-Chip RC Oscillator Option ..................................................................................... 115
23.2 External Clock Input Option ........................................................................................ 115
23.3 CPU Clock Rate select ............................................................................................... 116
24. POWER MONITORING .......................................................................................................... 117
24.1 Power On Detect ......................................................................................................... 117
24.2 Brownout Detect and Reset ........................................................................................ 117
25. ICP(IN-CIRCUIT PROGRAM) FLASH PROGRAM ................................................................. 119
26. CONFIG BITS ......................................................................................................................... 120
26.1 CONFIG0 .................................................................................................................... 120
26.2 CONFIG1 .................................................................................................................... 121
27. ELECTRICAL CHARACTERISTICS ....................................................................................... 123
27.1 Absolute Maximum Ratings ........................................................................................ 123
27.2 D.C. Characteristics .................................................................................................... 124
27.3 A.C. Characteristics .................................................................................................... 125
27.4 RC OSC AND AC CHARACTERISTICS .................................................................... 130
27.5 Typical Application Circuit ........................................................................................... 130
28. PACKAGE DIMENSIONS ....................................................................................................... 131
28.1 40-pin DIP ................................................................................................................... 131
28.2 44-pin PLCC ................................................................................................................ 132
28.3 44-pin PQFP ............................................................................................................... 133
28.4 48-pin LQFP ................................................................................................................ 134
29. REVISION HISTORY .............................................................................................................. 135
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Preliminary N79E352/N79E352R Data Sheet
- 4 -
1. GENERAL DESCRIPTION
The N79E352(R) is an 8-bit Turbo 51 microcontroller which has Flash EPROM programmable
hardware writer. The instruction set of the N79E352(R) is fully compatible with the standard 8052. The
N79E352(R) contains a 8Kbytes of main Flash EPROM; a 256 bytes of RAM; 128 bytes NVM Data
Flash EPROM; three 16-bit timer/counters; 2-channel 8-bit PWM; 1-channel UART and 1 additional
input capture. These peripherals are supported by 11 interrupt sources four-level interrupt capability.
To facilitate programming and verification, the Flash EPROM inside the N79E352(R) allows the
program memory to be programmed and read electronically. Once the code is confirmed, the user can
protect the code for security. N79E352(R) is designed for cost effective applications which can serve
industrial devices, and other low power applications.
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Preliminary N79E352/N79E352R Data Sheet
Publication Release Date: Jul, 29, 2009
- 5 - Revision A06
2. FEATURES
Fully static design 8-bit Turbo 51 CMOS microcontroller up to 24MHz when VDD=4.5V to 5.5V,
12MHz when VDD=2.7V to 5.5V, and 4MHz when VDD=2.4V to 5.5V.
8K bytes of AP Flash EPROM, with external writer programmable mode.
256 bytes of on-chip RAM.
128 bytes NVM Data Flash EPROM for customer data storage used and 10k writer cycles.
Instruction-set compatible with MCS-51.
On-chip configurable RC oscillator: 22.1184MHz/11.0592MHz (selectable by config bit) with ±2%
accuracy, at 5V voltage and 25°C condition. (±2% accuracy is only for N79E352R.)
Three 16-bit timer/counters.
One input capture.
11 interrupt source with four levels of priority.
One enhanced full duplex serial port with framing error detection and automatic address
recognition.
4 outputs mode and TTL/Schmitt trigger selectable Port.
Programmable Watchdog Timer with 20KHz internal RC clock can wake-up the power down
mode, and have very low power under 10uA at 5V.
Two-channel 8-bit PWM.
One I2C communication port.
Dual 16-bit Data Pointers.
Software programmable access cycle to external RAM/peripherals.
Eight keypads interrupt inputs with sharing the same interrupt source.
LED drive capability (20mA) on all port pins, total 100mA.
Low Voltage (3 levels) Detection interrupt and reset.
Industrial temperature grade -40oC~85oC.
Packages:
Lead Free (RoHS) DIP40: N79E352RADG
Lead Free (RoHS) PLCC44: N79E352RAPG
Lead Free (RoHS) PQFP44: N79E352RAFG
Lead Free (RoHS) LQFP48: N79E352RALG
Lead Free (RoHS) DIP40: N79E352ADG
Lead Free (RoHS) PLCC44: N79E352APG
Lead Free (RoHS) PQFP44: N79E352AFG
Lead Free (RoHS) LQFP48: N79E352ALG
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Preliminary N79E352/N79E352R Data Sheet
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3. PARTS INFORMATION LIST
3.1 Lead Free (RoHS) Parts information list
PART NO. EPROM
FLASH SIZE RAM NVM FLASH
EPROM
INTERNAL RC
OSCILLATOR
ACCURACY1 PACKAGE
N79E352RADG 8KB 256B 128B 22.1184MHz ± 2% DIP-40 Pin
N79E352RAPG 8KB 256B 128B 22.1184MHz ± 2% PLCC-44 Pin
N79E352RAFG 8KB 256B 128B 22.1184MHz ± 2% PQFP-44 Pin
N79E352RALG 8KB 256B 128B 22.1184MHz ± 2% LQFP-48 Pin
N79E352ADG 8KB 256B 128B 22MHz ± 25% DIP-40 Pin
N79E352APG 8KB 256B 128B 22MHz ± 25% PLCC-44 Pin
N79E352AFG 8KB 256B 128B 22MHz ± 25% PQFP-44 Pin
N79E352ALG 8KB 256B 128B 22MHz ± 25% LQFP-48 Pin
Table 3-1: Lead Free (RoHS) Parts information list
Note:
1. Factory calibration condition: VDD=5.0V±10%, TA = 25°C
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Preliminary N79E352/N79E352R Data Sheet
Publication Release Date: Jul, 29, 2009
- 7 - Revision A06
4. PIN CONFIGURATIONS
8
186
7
10
9
12
11
14
13
16
15
17
5
4
3
2
1
44
43
42
41
40
38
39
36
37
34
35
32
33
30
31
29
19
20
21
22
23
24
25
26
27
28
P1.6
PWM1, P1.5
RST
P1.7
P4.3
RXD, P3.0
TXD, P3.1
T0, P3.4
T1, P3.5
SCL, P1.3
SDA, P1.2
PWM0, P1.4
T2EX, P1.1
T2, P1.0
KB0, AD0, P0.0
P4.2
KB1, AD1, P0.1
KB2, AD2, P0.2
KB3, AD3, P0.3
VDD
ALE
P0.7, AD7, KB7
P4.1
P0.6, AD6, KB6
P0.5, AD5, KB5
P0.4, AD4, KB4
P2.5, A13
P2.6, A14
P2.7, A15
XTAL2, P5.2
XTAL1, P5.1
VSS
P2.1, A9
P4.0
P2.2, A10
P2.3, A11
P2.4, A12
P2.0, A8
PLCC 44-pin
INT0, P3.2
P3.7, RD
INT1, P3.3
PSEN
EA
P3.6, WR
10
9
12
11
14
13
16
15
17
P1.6
PWM1, P1.5
RST
P1.7
RXD, P3.0
TXD, P3.1
T0, P3.4
T1, P3.5
INT0, P3.2
INT1, P3.3
2
1
4
3
6
5
8
7
SCL, P1.3
SDA, P1.2
PWM0, P1.4
T2EX, P1.1
T2, P1.0
19
18
20
WR, P3.6
RD, P3.7
P5.0,XTAL2
P5.1,XTAL1
38
39
36
37
34
35
32
33
30
31
29
28
40
26
27
24
25
22
23
21
P2.1, A9
P2.2, A10
P2.3, A11
P2.4, A12
P2.0, A8
P2.5, A13
P2.6, A14
P2.7, A15
ALE
P0.7, AD7, KB7
P0.6, AD6, KB6
P0.5, AD5, KB5
P0.4, AD4, KB4
PSEN
EA
P0.0, AD0, KB0
P0.1, AD1, KB1
P0.2, AD2, KB2
P0.3, AD3, KB3
VDD
DIP 40-pin
VSS
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Preliminary N79E352/N79E352R Data Sheet
- 8 -
8
12
37
7
10
9
11
44
43
42
41
40
39
38
36
35
34
32
33
30
31
28
29
26
27
24
25
23
13
14
15
16
17
18
19
20
21
22
P1.6
RST
P1.7
RXD, P3.0
TXD, P3.1
T0, P3.4
T1, P3.5
T2EX, P1.1
T2, P1.0
VDD
ALE
P4.1
P2.5, A13
P2.6, A14
P2.7, A15
VSS
P2.1, A9
P4.0
P2.2, A10
P2.3, A11
P2.0, A8
LQFP 44-pin
INT0, P3.2
P3.7, RD
INT1, P3.3
PSEN
EA
P3.6, WR
2
1
4
3
5
6P4.3
P4.2
2
44
1
4
3
6
5
8
7
10
9
11
48
42
41
40
39
38
37
32
33
30
31
28
29
26
27
25
13
14
15
16
18
19
20
21
22
P2.7, A15
PSEN
ALE
EA
P4.1
P2.4, A12
P2.3, A11
P2.2, A10
P2.1, A9
P3.7, /RD
P3.6, /WR
P4.3
INT0, P3.2
INT1, P3.3
T0, P3.4
T1, P3.5
P1.6
P1.7
RST
P2.0, A8
P4.0
VSS
12
17
23
24
34
35
36
46
47
43
45
P2.6, A14
P2.5, A13
NC
VDD
P4.2
T2, P1.0
T2EX, P1.1
P3.1
P3.0
NC
NC
NC
LQFP 48-pin
P0.7, AD7, KB7
P0.6, AD6, KB6
P0.5, AD5, KB5
P0.4, AD4, KB4
KB0, AD0, P0.0
KB1, AD1, P0.1
KB2, AD2, P0.2
KB3, AD3, P0.3
PWM1, P1.5
SCL, P1.3
SDA, P1.2
PWM0, P1.4
XTAL2, P5.2
XTAL1, P5.1
PWM1, P1.5
SCL, P1.3
SDA, P1.2
PWM0, P1.4
XTAL2, P5.2
XTAL1, P5.1
KB0, AD0, P0.0
KB1, AD1, P0.1
KB2, AD2, P0.2
KB3, AD3, P0.3
P0.7, AD7, KB7
P0.6, AD6, KB6
P0.5, AD5, KB5
P0.4, AD4, KB4
P2.4, A12
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Preliminary N79E352/N79E352R Data Sheet
Publication Release Date: Jul, 29, 2009
- 9 - Revision A06
5. PIN DESCRIPTIONS
SYMBOL
Alternate
Function 1
Alternate
function 2
Type
DESCRIPTIONS
I
EXTERNAL ACCESS ENABLE: This pin forces the
processor to execute out of external ROM. It should
be kept high to access internal ROM. The ROM
address and data will not be present on the bus if
EA
pin is high and the program counter is within
internal ROM area. Otherwise they will be present on
the bus.
PSEN
O
PROGRAM STORE ENABLE: PSEN enables the
external ROM data onto the Port 0 address/data bus
during fetch and MOVC operations. When internal
ROM access is performed, no PSEN strobe signal
outputs from this pin.
ALE O ADDRESS LATCH ENABLE: ALE is used to enable
the address latch that separates the address from
the data on Port 0.
XTAL1 P5.1 I/O CRYSTAL1: This is the crystal oscillator input. This
pin may be driven by an external clock or
configurable i/o pin, P5.1.
XTAL2 P5.0 I/O CRYSTAL2: This is the crystal oscillator output. It is
the inversion of XTAL1. Also a configurable i/o pin,
P5.0.
VDD P POWER SUPPLY: Supply voltage for operation.
VSS P GROUND: Ground potential.
RST RESET: A high on this pin for two machine cycles
while the oscillator is running resets the device.
P0.0
KB0
AD0
I/O
PORT0:
Support 4 mode output and 2 mode input.
Multifunction pins for AD0-7and KB0-7.
P0.1
KB1
AD1
I/O
P0.2
KB2
AD2
I/O
P0.3
KB3
AD3
I/O
P0.4
KB4
AD4
I/O
P0.5
KB5
AD5
I/O
P0.6
KB6
AD6
I/O
P0.7
KB7
AD7
I/O
P1.0
T2
I/O
PORT1:
Support 4 mode output and 2 mode input.
Multifunction pins for SDA & SCL (I2C), T2, T2EX
and PWM0-1.
P1.1
T2EX
I/O
P1.2
SDA
I/O
P1.3
SCL
I/O
P1.4
PWM0
I/O
P1.5
PWM1
I/O
P1.6
ICPDAT
I/O
P1.7
ICPCLK
I/O
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Preliminary N79E352/N79E352R Data Sheet
- 10 -
P2.0
A8
I/O
PORT2:
Support 4 mode output and 2 mode input.
Multifunction pins for A8-A15,.
P2.1
A9
I/O
P2.2
A10
I/O
P2.3
A11
I/O
P2.4
A12
I/O
P2.5
A13
I/O
P2.6
A14
I/O
P2.7
A15
I/O
P3.0
RXD
I/O
PORT3:
Support 4 mode output and 2 mode input.
Multifunction pins for RXD & TXD (uart), /INT0,
/INT1, T0, T1, /WR and /RD.
P3.1
TXD
I/O
P3.2
/INT0
I/O
P3.3
/INT1
I/O
P3.4
T0
I/O
P3.5
T1
I/O
P3.6
/WR
I/O
P3.7
/RD
I/O
P4.0
I/O
PORT4:
Quasi output with internal pull up.
P4.1 I/O
P4.2 I/O
P4.3
I/O
* Note: TYPE I: input, O: output, I/O: bi-directional.
In application if any pins need external pull-up, it is recommended to add a pull-up resistor
(10k
)
between pin and power (VDD) instead of directly wiring pin to VDD for enhancing EMC.
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Preliminary N79E352/N79E352R Data Sheet
Publication Release Date: Jul, 29, 2009
- 11 - Revision A06
6. FUNCTIONAL DESCRIPTION
N79E352(R) architecture consist of a 4T 8051 core controller surrounded by various registers, 8K
bytes Flash EPROM, 256 bytes of RAM, 128 bytes NVM Data Flash EPROM; three timer/counters,
one UART serial port, one I2C serial port, eight keyboard interrupt input, 2-channel PWM with 8-bit
counter and Flash EPROM program by Writer.
6.1 On-Chip Flash EPROM
N79E352(R) includes one 8K bytes of main Flash EPROM for application program which need Writer
to program the Flash EPROM.
6.2 I/O Ports
N79E352(R) has four 8-bit, one 4-bit port and one 2-bit port, with at least 36 I/O pins. All ports (except
port 4) can be used as four outputs mode when it may set by PxM1.y and PxM2.y registers, it has
strong pull-ups and pull-downs, and does not need any external pull-ups. Otherwise it can be used as
general I/O port as open drain circuit. All ports can be used bi-directional and these are as I/O ports.
These ports are not true I/O, but rather are pseudo-I/O ports. This is because these ports have strong
pull-downs and weak pull-ups.
6.3 Serial I/O
N79E352(R) has one UART serial port that is functionally similar to the serial port of the original 8052
family. However the serial port on N79E352(R) can operate in different modes in order to obtain timing
similarity as well. The Serial port has the enhanced features of Automatic Address recognition and
Frame Error detection.
6.4 Timers
The device has total three 16-bit timers; two 16-bit timers that have functions similar to the timers of
the 8052 family, and third timer is capable to function as timer and also provide capture support. When
used as timers, user has a choice to set 12 or 4 clocks per count that emulates the timing of the
original 8052. Each timer’s count value is stored in two SFR locations that can be written or read by
software. There are also some other SFRs associated with the timers that control their mode and
operation.
6.5 Interrupts
The Interrupt structure in N79E352(R) is slightly different from that of the standard 8052. Due to the
presence of additional features and peripherals, the number of interrupt sources and vectors has been
increased.
6.6 Data Pointers
The original 8052 had only one 16-bit Data Pointer (DPL, DPH). In the N79E352(R), there is an
additional 16-bit Data Pointer (DPL1, DPH1). This new Data Pointer uses two SFR locations which
were unused in the original 8052. In addition there is an added instruction, DEC DPTR (op-code A5H),
which helps in improving programming flexibility for the user.
6.7 Architecture
N79E352(R) is based on the standard 8052 device. It is built around an 8-bit ALU that uses internal
registers for temporary storage and control of the peripheral devices. It can execute the standard 8052
instruction set.
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Preliminary N79E352/N79E352R Data Sheet
- 12 -
6.7.1 ALU
The ALU is the heart of the N79E352(R). It is responsible for the arithmetic and logical functions. It is
also used in decision making, in case of jump instructions, and is also used in calculating jump
addresses. The user cannot directly use the ALU, but the Instruction Decoder reads the op-code,
decodes it, and sequences the data through the ALU and its associated registers to generate the
required result. The ALU mainly uses the ACC which is a special function register (SFR) on the chip.
Another SFR, namely B register is also used in Multiply and Divide instructions. The ALU generates
several status signals which are stored in the Program Status Word register (PSW).
6.7.2 Accumulator
The Accumulator (ACC) is the primary register used in arithmetic, logical and data transfer operations
in N79E352(R). Since the Accumulator is directly accessible by the CPU, most of the high speed
instructions make use of the ACC as one argument.
6.7.3 B Register
This is an 8-bit register that is used as the second argument in the MUL and DIV instructions. For all
other instructions it can be used simply as a general purpose register.
6.7.4 Program Status Word:
This is an 8-bit SFR that is used to store the status bits of the ALU. It holds the Carry flag, the Auxiliary
Carry flag, General purpose flags, the Register Bank Select, the Overflow flag, and the Parity flag.
6.7.5 Scratch-pad RAM
N79E352(R) has a 256 bytes on-chip scratch-pad RAM. These can be used by the user for temporary
storage during program execution. A certain section of this RAM is bit addressable, and can be directly
addressed for this purpose.
6.7.6 Stack Pointer
N79E352(R) has an 8-bit Stack Pointer which points to the top of the Stack. This stack resides in the
Scratch Pad RAM. Hence the size of the stack is limited by the size of this RAM.
6.8 Power Management
Like the standard 80C52, the N79E352(R) also has IDLE and POWER DOWN modes of operation.
The N79E352(R) provides a new Economy mode which allow user to switch the internal clock rate
divided by either 4, 64 or 1024. In the IDLE mode, the clock to the CPU core is stopped while the
timers, serial ports and interrupts clock continue to operate. In the POWER DOWN mode, all the clock
are stopped and the chip operation is completely stopped. This is the lowest power consumption state.
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Preliminary N79E352/N79E352R Data Sheet
Publication Release Date: Jul, 29, 2009
- 13 - Revision A06
7. MEMORY ORGANIZATION
N79E352(R) separates the memory into two separate sections, the Program Memory and the Data
Memory. The Program Memory is used to store the instruction op-codes, while the Data Memory is
used to store data or for memory mapped devices.
8K Bytes
On-Chip
Code Memory
CONFIG 0
1FFFH
2000H
FC00H
CONFIG 1
FC7FH 128B
NVM
Data Memory
(MOVX)
NVM Data Flash Area
FC1Fh
FC10h
FC0Fh
FC00h
Page 0
Page 1
Page 7
Page 2
Page 3
Page 4
Page 5
Page 6
(128B NVM,
16bytes/page)
FC3Fh
FC30h
FC2Fh
FC20h
FC5Fh
FC50h
FC4Fh
FC40h
FC7Fh
FC70h
FC6Fh
FC60h
0000H
Program
Memory Space
FFFFH
External
Program
Memory
Figure 7-1: N79E352(R) Memory Map
7.1 Program Memory (on-chip Flash)
The Program Memory on N79E352(R) can be up to 8K bytes long. All instructions are fetched for
execution from this memory area. The MOVC instruction can also access this memory region.
n UVOTO n E
Preliminary N79E352/N79E352R Data Sheet
- 14 -
7.2 Data Memory
The N79E352(R) has NVM data memory of 128 bytes for customer’s data store used. The NVM data
memory has 8 pages area and each page has 16 bytes. The N79E352(R) can access up to 64Kbytes
of external Data Memory. This memory region is accessed by the MOVX instructions. For NVM s/w
read access, user require to set EnNVM bit, otherwise, the access will goes to external data memory.
N79E352(R) has the standard 256 bytes of on-chip Scratchpad RAM. This can be accessed either by
direct addressing or by indirect addressing. There are also some Special Function Registers (SFRs),
which can only be accessed by direct addressing. Since the Scratchpad RAM is only 256 bytes, it can
be used only when data contents are small.
7.3 Scratch-pad RAM and Register Map
As mentioned before, N79E352(R) has separate Program and Data Memory areas. The on-chip 256
bytes scratch pad RAM is in addition to the external memory. There are also several Special Function
Registers (SFRs) which can be accessed by software. The SFRs can be accessed only by direct
addressing, while the on-chip RAM can be accessed by either direct or indirect addressing.
Indirect
RAM
Addressing
Direct
&
Indirect
RAM
Addressing
SFR
Direct
Addressing
Only
00H
7FH
80H
FFH
Figure 7-2: N79E352(R) RAM and SFR Memory Map
Since the scratch-pad RAM is only 256 bytes it can be used only when data contents are small. There
are several other special purpose areas within the scratch-pad RAM. These are illustrated in next
figure.
n UVOTO n E
Preliminary N79E352/N79E352R Data Sheet
Publication Release Date: Jul, 29, 2009
- 15 - Revision A06
Bank 0
Bank 1
Bank 2
Bank 3
03 02 01 0004050607
0B 0A 09 080C0D0E0F
13 12 11 101415
1617
1B 1A 19 181C
1D1E
1F
23 22 21 2024252627
2B 2A 29 282C2D2E2F
33 32 31 30
34
3536
37
3B 3A 39 383C3D3E3F
43 42 41 4044
45
4647
4B 4A 49 48
4C4D
4E4F
53 52 51 50545556
57
5B 5A 59 585C5D5E5F
63 62 61 6064656667
6B 6A 69 68
6C
6D6E6F
73 72 71 7074
75
7677
7B 7A 79 78
7C7D
7E
7F
Direct RAM
Indirect RAM
00H
07H
28H
08H
0FH
10H
17H
18H
1FH
20H
21H
22H
23H
24H
25H
26H
27H
29H
2AH
2BH
2CH
2DH
2EH
2FH
30H
7FH
80H
FFH
Figure 7-3: Scratch-pad RAM
n UVOTO n
Preliminary N79E352/N79E352R Data Sheet
- 16 -
7.3.1 Working Registers
There are four sets of working registers, each consisting of eight 8-bit registers. These are termed as
Banks 0, 1, 2, and 3. Individual registers within these banks can be directly accessed by separate
instructions. These individual registers are named as R0, R1, R2, R3, R4, R5, R6 and R7. However, at
any one time N79E352 can work with only one particular bank. The bank selection is done by setting
RS1-RS0 bits in the PSW. The R0 and R1 registers are used to store the address for indirect
accessing.
7.3.2 Bit addressable Locations
The Scratch-pad RAM area from location 20h to 2Fh is byte as well as bit addressable. This means
that a bit in this area can be individually addressed. In addition some of the SFRs are also bit
addressable. The instruction decoder is able to distinguish a bit access from a byte access by the type
of the instruction itself. In the SFR area, any existing SFR whose address ends in a 0 or 8 is bit
addressable.
7.3.3 Stack
The scratch-pad RAM can be used for the stack. This area is selected by the Stack Pointer (SP), which
stores the address of the top of the stack. Whenever a jump, call or interrupt is invoked the return
address is placed on the stack. There is no restriction as to where the stack can begin in the RAM. By
default however, the Stack Pointer contains 07h at reset. The user can then change this to any value
desired. The SP will point to the last used value. Therefore, the SP will be incremented and then
address saved onto the stack. Conversely, while popping from the stack the contents will be read first,
and then the SP is decreased.
n UVOTO n =
Preliminary N79E352/N79E352R Data Sheet
Publication Release Date: Jul, 29, 2009
- 17 - Revision A06
8. SPECIAL FUNCTION REGISTERS
The N79E352(R) uses Special Function Registers (SFRs) to control and monitor peripherals and their
Modes.
The SFRs reside in the register locations 80-FFh and are accessed by direct addressing only. Some of
the SFRs are bit addressable. This is very useful in cases where one wishes to modify a particular bit
without changing the others. The SFRs that are bit addressable are those whose addresses end in 0 or
8. The N79E352(R) contains all the SFRs present in the standard 8052. However, some additional
SFRs have been added. In some cases unused bits in the original 8052 have been given new
functions. The list of SFRs is as follows. The table is condensed with eight locations per row. Empty
locations indicate that there are no registers at these addresses. When a bit or register is not
implemented, it will read high.
8.1 SFR Location Table
F8 IP1 FF
F0 B IP1H F7
E8 EIE KBL PORTS P5M1 P5M2 EF
E0 ACC CCL0 CCH0 E7
D8 WDCON PWM0L PWM1L PWMCON1 DF
D0 PSW PWMCON3 D7
C8 T2CON T2MOD RCAP2L RCAP2H TL2 TH2 NVMCON NVMDAT CF
C0 I2CON I2ADDR ROMMAP PMR STATUS NVMADDR TA C7
B8 IP0 SADEN I2DATA I2STATUS I2CLK I2TIMER BF
B0 P3 P0M1 P0M2 P1M1 P1M2 P2M1 P2M2 IP0H B7
A8 IE SADDR AF
A0 P2 KBI AUXR1 CAPCON0 CAPCON1 P4 A7
98 SCON SBUF P3M1 P3M2 9F
90 P1 P5 97
88 TCON TMOD TL0 TL1 TH0 TH1 CKCON 8F
80 P0 SP DPL DPH DPL1 DPH1 DPS PCON 87
Note: The SFRs in the column with dark borders are bit-addressable.
Table 8- 1: Special Function Register Location Table
n UVOTO n =
Preliminary N79E352/N79E352R Data Sheet
- 18 -
SYMBOL DEFINITION ADDRESS MSB BIT ADDRESS, SYMBOL LSB RESET
IP1 INTERRUPT PRIORITY 1 F8H PCAP PBO - PWDI - - PKB PI2 00x0 xx00B
IP1H INTERRUPT HIGH PRIORITY 1 F7H PCAPH PBOH - PWDIH - - PKBH PI2H 00x0 xx00B
B B REGISTER F0H B.7 B.6 B.5 B.4 B.3 B.2 B.1 B.0 0000 0000B
P5M2 PORT 5 OUTPUT MODE 2 EEH - - - - - - P5M2.1 P5M2.0 CONFIG0.PMOD
E=1;
Xxxx xx00B
CONFIG0.PMOD
E=0;
Xxxx xx11B
P5M1 PORT 5 OUTPUT MODE 1 EDH - - - - - ENCLK P5M1.1 P5M1.0 CONFIG0.PMOD
E=1;
Xxxx x000B
CONFIG0.PMOD
E=0;
Xxxx x011B
PORTS PORT SHMITT REGISTER ECH - - P5S - P3S P2S P1S P0S xx0x 0000B
KBL KEYBOARD LEVEL REGISTER E9H KBL.7 KBL.6 KBL.5 KBL.4 KBL.3 KBL.2 KBL.1 KBL.0 0000 0000B
EIE INTERRUPT ENABLE 1 E8H ECPTF EBO - EWDI - - EKB EI2 00x0 xx00B
CCH0 INPUT CAPTURE 0 HIGH E5H CCH0.7 CCH0.6 CCH0.5 CCH0.4 CCH0.3 CCH0.2 CCH0.1 CCH0.0 0000 0000B
CCL0 INPUT CAPTURE 0 LOW E4H CCL0.7 CCL0.6 CCL0.5 CCL0.4 CCL0.3 CCL0.2 CCL0.1 CCL0.0 0000 0000B
ACC ACCUMULATOR E0H ACC.7 ACC.6 ACC.5 ACC.4 ACC.3 ACC.2 ACC.1 ACC.0 0000 0000B
PWMCON1 PWM CONTROL REGISTER 1 DCH PWMRUN - - CLRPWM - - - - 0xx0 xxxxB
PWM1L PWM 1 LOW BITS REGISTER DBH PWM1.7 PWM1.6 PWM1.5 PWM1.4 PWM1.3 PWM1.2 PWM1.1 PWM1.0 0000 0000B
PWM0L PWM 0 LOW BITS REGISTER DAH PWM0.7 PWM0.6 PWM0.5 PWM0.4 PWM0.3 PWM0.2 PWM0.1 PWM0.0 0000 0000B
WDCON WATCH-DOG CONTROL D8H WDRUN POR - - WDIF WTRF EWRST WDCLR POR:
X1xx 0000B
External reset:
Xxxx 0xx0B
Watchdog reset:
Xxxx 01x0B
PWMCON3 PWM CONTROL REGISTER 3 D7H - - PWM1OE PWM0OE PCLK.1 PCLK.0 FP1 FP0 Xx00 0000B
PSW PROGRAM STATUS WORD D0H CY AC F0 RS1 RS0 OV F1 P 0000 0000B
NVMDATA NVM DATA CFH NVMDATA.7 NVMDATA.6 NVMDATA.5 NVMDATA.4 NVMDATA.
3 NVMDATA.
2 NVMDATA.
1 NVMDATA.
0 0000 0000B
NVMCON NVM CONTROL CEH EER EWR EnNVM - - - - - 000x xxxxB
TH2 TIMER 2 MSB CDH TH2.7 TH2.6 TH2.5 TH2.4 TH2.3 TH2.2 TH2.1 TH2.0 0000 0000B
TL2 TIMER 2 LSB CCH TL2.7 TL2.6 TL2.5 TL2.4 TL2.3 TL2.2 TL2.1 TL2.0 0000 0000B
RCAP2H TIMER 2 RELOAD MSB CBH RCAP2H.7 RCAP2H.6 RCAP2H.5 RCAP2H.4 RCAP2H.3 RCAP2H.2 RCAP2H.1 RCAP2H.0 0000 0000B
RCAP2L TIMER 2 RELOAD LSB CAH RCAP2L.7 RCAP2L.6 RCAP2L.5 RCAP2L.4 RCAP2L.3 RCAP2L.2 RCAP2L.1 RCAP2L.0 0000 0000B
T2MOD TIMER 2 MODE C9H - - - ICEN0 T2CR 1 T2OE DCEN Xxx0 0100B
T2CON TIMER 2 CONTROL C8H TF2 EXF2 RCLK TCLK EXEN2 TR2 C/T2 CP/RL 0000 0000B
TA TIMED ACCESS PROTECTION C7H TA.7 TA.6 TA.5 TA.4 TA.3 TA.2 TA.1 TA.0 0000 0000B
NVMADDR NVM LOW BYTE ADDRESS C6H NVMADDR.7 NVMADDR.6 NVMADDR.5 NVMADDR.4 NVMADDR.
3 NVMADDR.
2 NVMADDR.
1 NVMADDR.
0 0000 0000B
STATUS STATUS REGISTER C5H - - - - - - SPTA0 SPRA0 Xxxx xx00B
PMR POWER MANAGEMENT
REGISTER C4H CD1 CD0 SWB - - ALE-OFF - - 010x xxxxB
ROMMAP ROMMAP REGISTER C2H WS 1 - - - 1 1 0 01xxx110B
I2ADDR I2C ADDRESS1 C1H ADDR.7 ADDR.6 ADDR.5 ADDR.4 ADDR.3 ADDR.2 ADDR.1 GC xxxxxxx0B
n UVOTO n =
Preliminary N79E352/N79E352R Data Sheet
Publication Release Date: Jul, 29, 2009
- 19 - Revision A06
SYMBOL DEFINITION ADDRESS MSB BIT ADDRESS, SYMBOL LSB RESET
I2CON I2C CONTROL REGISTER C0H - ENSI STA STO SI AA - - x00000xxB
I2TIMER I2C TIMER COUNTER REGISTER BFH - - - - - ENTI DIV4 TIF Xxxx x000B
I2CLK I2C CLOCK RATE BEH I2CLK.7 I2CLK.6 I2CLK.5 I2CLK.4 I2CLK.3 I2CLK.2 I2CLK.1 I2CLK.0 0000 0000B
I2STATUS I2C STATUS BDH I2STATUS.7 I2STATUS.6 I2STATUS.5 I2STATUS.4 I2STATUS.
3 I2STATUS.
2 I2STATUS.
1 I2STATUS.
0 1111 1000B
I2DAT I2C DATA BCH I2DAT.7 I2DAT.6 I2DAT.5 I2DAT.4 I2DAT.3 I2DAT.2 I2DAT.1 I2DAT.0 xxxxxxxxB
SADEN SLAVE ADDRESS MASK B9H SADEN.7 SADEN.6 SADEN.5 SADEN.4 SADEN.3 SADEN.2 SADEN.1 SADEN.0 00000000B
IP0 INTERRUPT PRIORITY B8H - - PT2 PS PT1 PX1 PT0 PX0 Xx00 0000B
IP0H INTERRUPT HIGH PRIORITY B7H - - PT2H PSH PT1H PX1H PT0H PX0H Xx00 0000B
P2M2 PORT 2 OUTPUT MODE 2 B6H P2M2.7 P2M2.6 P2M2.5 P2M2.4 P2M2.3 P2M2.2 P2M2.1 P2M2.0 CONFIG0.PMOD
E=1;
0000 0000B
CONFIG0.PMOD
E=0;
1111 1111B
P2M1 PORT 2 OUTPUT MODE 1 B5H P2M1.7 P2M1.6 P2M1.5 P2M1.4 P2M1.3 P2M1.2 P2M1.1 P2M1.0 CONFIG0.PMOD
E=1;
0000 0000B
CONFIG0.PMOD
E=0;
1111 1111B
P1M2 PORT 1 OUTPUT MODE 2 B4H P1M2.7 P1M2.6 P1M2.5 P1M2.4 P1M2.3 P1M2.2 P1M2.1 P1M2.0 CONFIG0.PMOD
E=1;
0000 0000B
CONFIG0.PMOD
E=0;
1111 1111B
P1M1 PORT 1 OUTPUT MODE 1 B3H P1M1.7 P1M1.6 P1M1.5 P1M1.4 P1M1.3 P1M1.2 P1M1.1 P1M1.0 CONFIG0.PMOD
E=1;
0000 0000B
CONFIG0.PMOD
E=0;
1111 1111B
P0M2 PORT 0 OUTPUT MODE 2 B2H P0M2.7 P0M2.6 P0M2.5 P0M2.4 P0M2.3 P0M2.2 P0M2.1 P0M2.0 1111 1111B
P0M1 PORT 0 OUTPUT MODE 1 B1H P0M1.7 P0M1.6 P0M1.5 P0M1.4 P0M1.3 P0M1.2 P0M1.1 P0M1.0 1111 1111B
P3 PORT3 B0H P3.7 P3.6 P3.5 P3.4 P3.3 P3.2 P3.1 P3.0 1111 1111B
/RD /WR T1 T0 /INT1 /INT0 TXD RXD
SADDR SLAVE ADDRESS A9H SADDR.7 SADDR.6 SADDR.5 SADDR.4 SADDR.3 SADDR.2 SADDR.1 SADDR.0 0000 0000B
IE INTERRUPT ENABLE A8H EA - ET2 ES ET1 EX1 ET0 EX0 0x00 0000B
P4 PORT4 A5H - - - - P4.3 P4.2 P4.1 P4.0 Xxxx 1111B
CAPCON1 CAPTURE CONTROL 1 A4H 0 T0CC - - ENF0 - - CPTF0 00xx 0xx0B
CAPCON0 CAPTURE CONTROL 0 A3H - - - - CCT0.1 CCT0.0 - - Xxxx 00xxB
AUXR1 AUX FUNCTION REGISTER 1 A2H KBF BOD BOI LPBOV SRST BOV1 BOV0 BOS 0000 0000B
KBI KEYBOARD INTERRUPT A1H KBI.7 KBI.6 KBI.5 KBI.4 KBI.3 KBI.2 KBI.1 KBI.0 0000 0000B
P2 PORT 2 A0H P2.7 P2.6 P2.5 P2.4 P2.3 P2.2 P2.1 P2.0 1111 1111B
A15 A14 A13 A12 A11 A10 A9 A8
P3M2 PORT 3 OUTPUT MODE 2 9FH P3M2.7 P3M2.6 P3M2.5 P3M2.4 P3M2.3 P3M2.2 P3M2.1 P3M2.0 CONFIG0.PMOD
E=1;
0000 0000B
CONFIG0.PMOD
E=0;
1111 1111B
n UVOTO n =
Preliminary N79E352/N79E352R Data Sheet
- 20 -
SYMBOL DEFINITION ADDRESS MSB BIT ADDRESS, SYMBOL LSB RESET
P3M1 PORT 3 OUTPUT MODE 1 9EH P3M1.7 P3M1.6 P3M1.5 P3M1.4 P3M1.3 P3M1.2 P3M1.1 P3M1.0 CONFIG0.PMOD
E=1;
0000 0000B
CONFIG0.PMOD
E=0;
1111 1111B
SBUF SERIAL BUFFER 99H SBUF.7 SBUF.6 SBUF.5 SBUF.4 SBUF.3 SBUF.2 SBUF.1 SBUF.0 Xxxx xxxxB
SCON SERIAL CONTROL 98H SM0/FE SM1 SM2 REN TB8 RB8 TI RI 0000 0000B
P5 PORT5 94H - - - - - - P5.1 P5.0 Xxxx xx11B
- - - - - - XTAL1 XTAL2
- - - - - - - CLKOUT
P1 PORT 1 90H P1.7 P1.6 P1.5 P1.4 P1.3 P1.2 P1.1 P1.0 1111 1111B
- - PWM1 PWM0 SCL SDA T2EX T2
CKCON CLOCK CONTROL 8EH WD1 WD0 T2M T1M T0M MD2 MD1 MD0 0000 0001B
TH1 TIMER HIGH 1 8DH TH1.7 TH1.6 TH1.5 TH1.4 TH1.3 TH1.2 TH1.1 TH1.0 0000 0000B
TH0 TIMER HIGH 0 8CH TH0.7 TH0.6 TH0.5 TH0.4 TH0.3 TH0.2 TH0.1 TH0.0 0000 0000B
TL1 TIMER LOW 1 8BH TL1.7 TL1.6 TL1.5 TL1.4 TL1.3 TL1.2 TL1.1 TL1.0 0000 0000B
TL0 TIMER LOW 0 8AH TL0.7 TL0.6 TL0.5 TL0.4 TL0.3 TL0.2 TL0.1 TL0.0 0000 0000B
TMOD TIMER MODE 89H GATE C/T M1 M0 GATE C/T M1 M0 0000 0000B
TCON TIMER CONTROL 88H TF1 TR1 TF0 TR0 IE1 IT1 IE0 IT0 0000 0000B
PCON POWER CONTROL 87H SM0D SMOD0 BOF - GF1 GF0 PD IDL 001x 0000B
DPS DATA POINTER SELECT 86H - - - - - - - DPS.0 Xxxx xxx0B
DPH1 DATA POINTER HIGH 1 85H DPH1.7 DPH1.6 DPH1.5 DPH1.4 DPH1.3 DPH1.2 DPH1.1 DPH1.0 0000 0000B
DPL1 DATA POINTER LOW 1 84H DPL1.7 DPL1.6 DPL1.5 DPL1.4 DPL1.3 DPL1.2 DPL1.1 DPL1.0 0000 0000B
DPH DATA POINTER HIGH 83H DPH.7 DPH.6 DPH.5 DPH.4 DPH.3 DPH.2 DPH.1 DPH.0 0000 0000B
DPL DATA POINTER LOW 82H DPL.7 DPL.6 DPL.5 DPL.4 DPL.3 DPL.2 DPL.1 DPL.0 0000 0000B
SP STACK POINTER 81H SP.7 SP.6 SP.5 SP.4 SP.3 SP.2 SP.1 SP.0 0000 0111B
P0 PORT 0 80H P0.7 P0.6 P0.5 P0.4 P0.3 P0.2 P0.1 P0.0 1111 1111B
AD7 AD6
AD5
AD4
AD3
AD2
AD1
AD0
KB7 KB6
KB5
KB4
KB3
KB2
KB1
KB0
n UVOTO n E
Preliminary N79E352/N79E352R Data Sheet
Publication Release Date: Jul, 29, 2009
- 21 - Revision A06
8.2 SFR Detail Bit Descriptions
PORT 0
Bit:
7
6
5
4
3
2
1
0
P0.7
P0.6
P0.5
P0.4
P0.3
P0.2
P0.1
P0.0
Mnemonic: P0 Address: 80h
Port 0 is an open-drain bi-directional I/O port. This port provides a multiplexed low order address/data
bus during accesses to external memory. The ports also support alternate input function for Keyboard
pins (KB0-7).
BIT NAME FUNCTION
7 P0.7 AD7 or KB7 or I/O pin by alternative.
6 P0.6 AD6 or KB6 or I/O pin by alternative.
5 P0.5 AD5 or KB5 or I/O pin by alternative.
4 P0.4 AD4 or KB4 or I/O pin by alternative.
3 P0.3 AD3 or KB3 or I/O pin by alternative.
2 P0.2 AD2 or KB2 or I/O pin by alternative.
1 P0.1 AD1 or KB1 or I/O pin by alternative.
0 P0.0 AD0 or KB0 or I/O pin by alternative.
Note: The initial value of the port is set by CONFIG0.PRHI bit. The default setting for CONFIG0.PRHI =1 which the alternative
function output is turned on upon reset. If CONFIG0.PRHI is set to 0, the user has to write a 1 to port SFR to turn on the
alternative function output.
STACK POINTER
Bit: 7 6 5 4 3 2 1 0
SP.7
SP.6
SP.5
SP.4
SP.3
SP.2
SP.1
SP.0
Mnemonic: SP Address: 81h
BIT NAME FUNCTION
7-0 SP.[7:0] The Stack Pointer stores the Scratch-pad RAM address where the stack begins.
In other words it always points to the top of the stack.
DATA POINTER LOW
Bit:
7
6
5
4
3
2
1
0
DPL.7
DPL.6
DPL.5
DPL.4
DPL.3
DPL.2
DPL.1
DPL.0
Mnemonic: DPL Address: 82h
BIT NAME FUNCTION
7-0 DPL.[7:0] This is the low byte of the standard 8052 16-bit data pointer.
DATA POINTER HIGH
Bit: 7 6 5 4 3 2 1 0
n UVOTO n =
Preliminary N79E352/N79E352R Data Sheet
- 22 -
DPH.7
DPH.6
DPH.5
DPH.4
DPH.3
DPH.2
DPH.1
DPH.0
Mnemonic: DPH Address: 83h
BIT NAME FUNCTION
7-0 DPH.[7:0] This is the high byte of the standard 8052 16-bit data pointer.
This is the high byte of the DPTR 16-bit data pointer.
DATA POINTER LOW 1
Bit:
7
6
5
4
3
2
1
0
DPL1.7
DPL1.6
DPL1.5
DPL1.4
DPL1.3
DPL1.2
DPL1.1
DPL1.0
Mnemonic: DPL1 Address: 84h
BIT NAME FUNCTION
7-0 DPL1.[7:0] This is the low byte of the new additional 16-bit data pointer that has been added
to the N79E352(R). The user can switch between DPL, DPH and DPL1, DPH1
simply by setting register DPS = 1. The instructions that use DPTR will now
access DPL1 and DPH1 in place of DPL and DPH. If they are not required they
can be used as conventional register locations by the user.
DATA POINTER HIGH 1
Bit:
7
6
5
4
3
2
1
0
DPH1.7
DPH1.6
DPH1.5
DPH1.4
DPH1.3
DPH1.2
DPH1.1
DPH1.0
Mnemonic: DPH1 Address: 85h
BIT NAME FUNCTION
7-0 DPH1.[7:0] This is the high byte of the new additional 16-bit data pointer that has been
added to the N79E352(R). The user can switch between DPL, DPH and DPL1,
DPH1 simply by setting register DPS = 1. The instructions that use DPTR will
now access DPL1 and DPH1 in place of DPL and DPH. If they are not required
they can be used as conventional register locations by the user.
DATA POINTER SELECT
Bit:
7
6
5
4
3
2
1
0
- - - - - - - DPS.0
Mnemonic: DPS Address: 86h
BIT NAME FUNCTION
7-1 - Reserved.
0 DPS This bit is used to select either the DPL,DPH pair or the DPL1,DPH1 pair as the
active Data Pointer. When set to 1, DPL1, DPH1 will be selected, otherwise DPL,
DPH will be selected.
POWER CONTROL
Bit:
7
6
5
4
3
2
1
0
n UVOTO n E
Preliminary N79E352/N79E352R Data Sheet
Publication Release Date: Jul, 29, 2009
- 23 - Revision A06
SMOD
SMOD0
BOF
-
GF1
GF0
PD
IDL
Mnemonic: PCON Address: 87h
BIT NAME FUNCTION
7 SMOD 1: This bit doubles the serial port baud rate in mode 1, 2, and 3.
6 SMOD0
0: Framing Error Detection Disable. SCON.7 (SM0/FE) bit is used as SM0
(standard 8052 function).
1: Framing Error Detection Enable. SCON.7 (SM0/FE) bit is used to reflect as
Frame Error (FE) status flag.
5 BOF
0: Cleared by software.
1: Set automatically when a brownout reset or interrupt has occurred. Also set at
power on.
4 - Reserved.
3 GF1 General purpose user flags.
2 GF0 General purpose user flags.
1 PD 1: The CPU goes into the POWER DOWN mode. In this mode, all the clocks are
stopped and program execution is frozen.
0 IDL 1: The CPU goes into the IDLE mode. In this mode, the clocks CPU clock
stopped, so program execution is frozen. But the clock to the serial, timer and
interrupt blocks is not stopped, and these blocks continue operating.
TIMER CONTROL
Bit: 7 6 5 4 3 2 1 0
TF1 TR1 TF0 TR0 IE1 IT1 IE0 IT0
Mnemonic: TCON Address: 88h
BIT NAME FUNCTION
7 TF1 Timer 1 Overflow Flag. This bit is set when Timer 1 overflows. It is cleared
automatically when the program does a timer 1 interrupt service routine.
Software can also set or clear this bit.
6 TR1 Timer 1 Run Control. This bit is set or cleared by software to turn timer/counter
on or off.
5 TF0 Timer 0 Overflow Flag. This bit is set when Timer 0 overflows. It is cleared
automatically when the program does a timer 0
interrupt service routine.
Software can also set or clear this bit.
4 TR0 Timer 0 Run Control. This bit is set or cleared by software to turn timer/counter
on or off.
3 IE1
Interrupt 1 Edge Detect Flag: Set by hardware when an edge/level is detected on
INT1
. This bit is cleared by hardware when the service routine is vectored to only
if the interrupt was edge triggered. Otherwise it follows the inverse of the pin.
2 IT1 Interrupt 1 Type Control. Set/cleared by software to specify falling edge/ low level
triggered external inputs.
1 IE0 Interrupt 0 Edge Detect Flag. Set by hardware when an edge/level is detected on
n UVOTO n E W W M1 M0: Mode Select bits:
Preliminary N79E352/N79E352R Data Sheet
- 24 -
INT0
. This bit is cleared by hardware when the service routine is vectored to
only if the interrupt was edge triggered. Otherwise it follows the inverse of the pin.
0 IT0 Interrupt 0 Type Control: Set/cleared by software to specify falling edge/ low level
triggered external inputs.
TIMER MODE CONTROL
Bit:
7
6
5
4
3
2
1
0
GATE
TC/
M1
M0
GATE
TC/
M1
M0
TIMER1
TIMER0
Mnemonic: TMOD Address: 89h
BIT NAME FUNCTION
7 GATE
Gating control: When this bit is set, Timer/counter 1 is enabled only while the
INT1
pin is high and the TR1 control bit is set. When cleared, the
INT1
pin has
no effect, and Timer 1 is enabled whenever TR1 control bit is set.
6
TC/
Timer or Counter Select: When clear, Timer 1 is incremented by the internal
clock. When set, the timer counts falling edges on the T1 pin.
5 M1 Timer 1 mode select bit 1. See table below.
4 M0 Timer 1 mode select bit 0. See table below.
3 GATE
Gating control: When this bit is set, Timer/counter 0 is enabled only while the
INT0
pin is high and the TR0 control bit is set. When cleared, the
INT0
pin has
no effect, and Timer 0 is enabled whenever TR0 control bit is set.
2
TC/
Timer or Counter Select: When clear, Timer 0 is incremented by the internal
clock. When set, the timer counts falling edges on the T0 pin.
1 M1 Timer 0 mode select bit 1. See table below.
0 M0 Timer 0 mode select bit 0. See table below.
M1, M0: Mode Select bits:
M1 M0 MODE
0 0 Mode 0: 8-bit timer/counter TLx serves as 5-bit pre-scale.
0 1 Mode 1: 16-bit timer/counter, no pre-scale.
1 0 Mode 2: 8-bit timer/counter with auto-reload from THx.
1 1 Mode 3: (Timer 0) TL0 is an 8-bit timer/counter controlled by the standard Timer0
control bits. TH0 is an 8-bit timer only controlled by Timer1 control bits. (Timer 1)
Timer/Counter 1 is stopped.
TIMER 0 LSB
Bit: 7 6 5 4 3 2 1 0
TL0.7 TL0.6 TL0.5 TL0.4 TL0.3 TL0.2 TL0.1 TL0.0
Mnemonic: TL0 Address: 8Ah
n UVOTO n
Preliminary N79E352/N79E352R Data Sheet
Publication Release Date: Jul, 29, 2009
- 25 - Revision A06
BIT NAME FUNCTION
7-0 TL0.[7:0] Timer 0 LSB.
TIMER 1 LSB
Bit:
7
6
5
4
3
2
1
0
TL1.7
TL1.6
TL1.5
TL1.4
TL1.3
TL1.2
TL1.1
TL1.0
Mnemonic: TL1 Address: 8Bh
BIT NAME FUNCTION
7-0 TL1.[7:0] Timer 1 LSB.
TIMER 0 MSB
Bit:
7
6
5
4
3
2
1
0
TH0.7
TH0.6
TH0.5
TH0.4
TH0.3
TH0.2
TH0.1
TH0.0
Mnemonic: TH0 Address: 8Ch
BIT NAME FUNCTION
7-0 TH0.[7:0] Timer 0 MSB.
TIMER 1 MSB
Bit:
7
6
5
4
3
2
1
0
TH1.7
TH1.6
TH1.5
TH1.4
TH1.3
TH1.2
TH1.1
TH1.0
Mnemonic: TH1 Address: 8Dh
BIT NAME FUNCTION
7-0 TH1.[7:0] Timer 1 MSB.
CLOCK CONTROL
Bit:
7
6
5
4
3
2
1
0
WD1
WD0
T2M
T1M
T0M
MD2
MD1
MD0
Mnemonic: CKCON Address: 8Eh
BIT NAME FUNCTION
7-5 WD1~0
Watchdog timer mode select bits: These bits determine the time-
out period for
the watchdog timer. In all four time-out options the reset time-
out is 512 clocks
more than the interrupt time-out period.
WD1 WD0 Interrupt time-out Reset time-out
0 0 2
6
2
6
+ 512
0 1 2
9
2
9
+ 512
1 0 213
213 + 512
1 1 2
15
2
15
+ 512
n UVOTO n =
Preliminary N79E352/N79E352R Data Sheet
- 26 -
BIT NAME FUNCTION
5 T2M
Timer 2 clock select:
0: Timer 2 uses a divide by 12 clocks.
1: Timer 2 uses a divide by 4 clocks.
4 T1M
Timer 1 clock select:
0: Timer 1 uses a divide by 12 clocks.
1: Timer 1 uses a divide by 4 clocks.
3 T0M
Timer 0 clock select:
0: Timer 0 uses a divide by 12 clocks.
1: Timer 0 uses a divide by 4 clocks.
2~0 MD2~0
Stretch MOVX select bits: These three bits are used to select the stretch value
for the MOVX instruction. Using a variable MOVX length enables the user to
access slower external memory devices or peripherals without the need for
external circuits. The
RD
or
WR
strobe will be stretched by the selected
interval. When accessing the on-chip SRAM, the MOVX instruction is always in 2
machine cycles regardless of the stretch setting. By default, the stretch has value
of 1. If the user needs faster accessing, then a stretch value of 0 should be
selected.
MD2 MD1 MD0 Stretch value MOVX duration
0 0 0 0 2 machine cycles
0 0 1 1 3 machine cycles (Default)
0 1 0 2 4 machine cycles
0 1 1 3 5 machine cycles
1 0 0 4 6 machine cycles
1 0 1 5 7 machine cycles
1 1 0 6 8 machine cycles
1 1 1 7 9 machine cycles
PORT 1
Bit: 7 6 5 4 3 2 1 0
P1.7 P1.6 P1.5 P1.4 P1.3 P1.2 P1.1 P1.0
Mnemonic: P1 Address: 90h
P1.7-0: General purpose Input/Output port. Most instructions will read the port pins in case of a port
read access, however in case of read-modify-write instructions, the port latch is read. These alternate
functions are described below:
BIT NAME FUNCTION
7 P1.7 Dedicated I/O pin.
6 P1.6 Dedicated I/O pin.
5 P1.5 PWM1 or I/O pin by alternative.
4 P1.4 PWM0 or I/O pin by alternative.
n UVOTO n E
Preliminary N79E352/N79E352R Data Sheet
Publication Release Date: Jul, 29, 2009
- 27 - Revision A06
BIT NAME FUNCTION
3 P1.3 SCL or I/O pin by alternative.
2 P1.2 SDA or I/O pin by alternative.
1 P1.1 T2EX or I/O pin by alternative.
0 P1.0 T2 or I/O pin by alternative.
PORT 5
Bit:
7
6
5
4
3
2
1
0
- - - - - - P5.1/
XTAL1
P5.0/
XTAL2/
CLKOUT
Mnemonic: P5 Address: 94h
BIT NAME FUNCTION
7~2 - Reserved.
1 P5.1 XTAL1 clock input or I/O pin by alternative.
0 P5.0 XTAL2 or CLKOUT pin or I/O pin by alternative.
SERIAL PORT CONTROL
Bit:
7
6
5
4
3
2
1
0
SM0/FE
SM1
SM2
REN
TB8
RB8
TI
RI
Mnemonic: SCON Address: 98h
BIT NAME FUNCTION
7 SM0/FE
Serial port mode select bit 0 or Framing Error Flag: The SMOD0 bit in PCON
SFR determines whether this bit acts as SM0 or as FE. The operation of SM0 is
described below. When used as FE, this bit will be set to indicate an invalid stop
bit. This bit must be manually cleared in software to clear the FE condition.
6 SM1 Serial Port mode select bit 1. See table below.
5 SM2
Multiple processors communication. Setting this bit to 1 enables the
multiprocessor communication feature in mode 2 and 3. In mode 2 or 3, if SM2 is
set to 1, then RI will not be activated if the received 9th data bit (RB8) is 0. In
mode 1, if SM2 = 1, then RI will not be activated if a valid stop bit was not
received. In mode 0, the SM2 bit controls the serial port clock. If set to 0, then the
serial port runs at a divide by 12 clock of the oscillator. This gives compatibility
with the standard 8052. When set to 1, the serial clock become divide by 4 of the
oscillator clock. This results in faster synchronous serial communication.
4 REN
Receive enable:
0: Disable serial reception.
1: Enable serial reception.
3 TB8 This is the 9th bit to be transmitted in modes 2 and 3. This bit is set and cleared
by software as desired.
2 RB8 In modes 2 and 3 this is the received 9th data bit. In mode 1, if SM2 = 0, RB8 is
n UVOTO n = 3M1 3M0: Mode Select bits:
Preliminary N79E352/N79E352R Data Sheet
- 28 -
BIT NAME FUNCTION
the stop bit that was received. In mode 0 it has no function.
1 TI Transmit interrupt flag: This flag is set by hardware at the end of the 8th bit time
in mode 0, or at the beginning of the stop bit in all other modes during serial
transmission. This bit must be cleared by software.
0 RI
Receive interrupt flag: This flag is set by hardware at the end of the 8th bit time in
mode 0, or halfway through the stop bits time in the other modes during serial
reception. However the
restrictions of SM2 apply to this bit. This bit can be
cleared only by software.
SM1, SM0: Mode Select bits:
MODE SM1 SM0 DESCRIPTION LENGTH BAUD RATE
0 0 0 Synchronous 8 FCPU divided by 4 or 12
1 0 1 Asynchronous 10 Variable
2 1 0 Asynchronous 11 FCPU divided by 32 or 64
3 1 1 Asynchronous 11 Variable
SERIAL DATA BUFFER
Bit:
7
6
5
4
3
2
1
0
SBUF.7
SBUF.6
SBUF.5
SBUF.4
SBUF.3
SBUF.2
SBUF.1
SBUF.0
Mnemonic: SBUF Address: 99h
BIT NAME FUNCTION
7-0 SBUF.[7:0]
Serial data on the serial port is read from or written to this location. It actually
consists of two separate internal 8-bit registers. One is the receive resister, and
the other is the transmit buffer. Any read access gets data from the receive data
buffer, while write access is to the transmit data buffer.
PORT 3 OUTPUT MODE 1
Bit:
7
6
5
4
3
2
1
0
P3M1.7 P3M1.6 P3M1.5 P3M1.4 P3M1.3 P3M1.2 P3M1.1 P3M1.0
Mnemonic: P3M1 Address: 9Eh
BIT NAME FUNCTION
7-0 P3M1.7-0 To control the output configuration of P3 [7:0].
PORT 3 OUTPUT MODE 2
Bit: 7 6 5 4 3 2 1 0
P3M2.7 P3M2.6 P3M2.5 P3M2.4 P3M2.3 P3M2.2 P3M2.1 P3M2.0
Mnemonic: P3M2 Address: 9Fh
BIT NAME FUNCTION
7-0 P3M2.7-0 See as below table.
n UVOTO n = Port Outgm Configuratwon Seflings:
Preliminary N79E352/N79E352R Data Sheet
Publication Release Date: Jul, 29, 2009
- 29 - Revision A06
Port Output Configuration Settings:
PXM1.Y PXM2.Y PORT INPUT/OUTPUT MODE
0 0 Quasi-bidirectional
0 1 Push-Pull
1 0
Input Only (High Impedance)
PORTS.PxS=0, TTL input
PORTS.PxS=1, Schmitt input
1 1 Open Drain
Note:
1. X = 0-3, 5. Y = 0-7.
2. CONFIG0.PMODE bit will determine the port1~3 and port 5 are Quasi or Open drain upon reset. See detail PMODE
descriptions.
PORT 2
Bit:
7
6
5
4
3
2
1
0
P2.7
P2.6
P2.5
P2.4
P2.3
P2.2
P2.1
P2.0
Mnemonic: P2 Address: A0h
P2.7-0: Port 2 is a bi-directional I/O port with internal pull-ups. This port also provides the upper
address bits for accesses to external memory.
BIT NAME FUNCTION
7 P2.7 A15 or I/O pin by alternative.
6 P2.6 A14 or I/O pin by alternative.
5 P2.5 A13 or I/O pin by alternative.
4 P2.4 A12 or I/O pin by alternative.
3 P2.3 A11 or I/O pin by alternative.
2 P2.2 A10 or I/O pin by alternative.
1 P2.1 A9 or I/O pin by alternative.
0 P2.0 A8 or I/O pin by alternative.
KEYBOARD INTERRUPT
Bit:
7
6
5
4
3
2
1
0
KBI.7
KBI.6
KBI.5
KBI.4
KBI.3
KBI.2
KBI.1
KBI.0
Mnemonic: KBI Address: A1h
BIT NAME FUNCTION
7 KBI.7 1: Enable P0.7 as a cause of a Keyboard interrupt.
6 KBI.6 1: Enable P0.6 as a cause of a Keyboard interrupt.
5 KBI.5 1: Enable P0.5 as a cause of a Keyboard interrupt.
4 KBI.4 1: Enable P0.4 as a cause of a Keyboard interrupt.
n UVOTO n = fion the un uh enabb have
Preliminary N79E352/N79E352R Data Sheet
- 30 -
3 KBI.3 1: Enable P0.3 as a cause of a Keyboard interrupt.
2 KBI.2 1: Enable P0.2 as a cause of a Keyboard interrupt.
1 KBI.1 1: Enable P0.1 as a cause of a Keyboard interrupt.
0 KBI.0 1: Enable P0.0 as a cause of a Keyboard interrupt.
AUX FUNCTION REGISTER 1
Bit: 7 6 5 4 3 2 1 0
KBF BOD BOI LPBOV SRST BOV1 BOV0 BOS
Mnemonic: AUXR1 Address: A2h
BIT NAME FUNCTION
7 KBF
Keyboard Interrupt Flag:
1: When any pin of port 0 that is enabled for the Keyb
oard Interrupt function
triggers (trigger level is depending on SFR KBL configuration).
Must be cleared by
software.
6 BOD
Brown Out Disable:
0: Enable Brownout Detect function.
1: Disable Brownout Detect function and save power.
BOD is initialized at all resets with the inverse value of bit CBOD in config0.3 bit.
User is able to re-configure this bit after reset.
5 BOI
Brown Out Interrupt:
0: Disable Brownout Detect Interrupt function.
1: This prevents brownout detection from causing a chip reset and allows the
Brownout Detect function to be used as an interrupt.
4 LPBOV
Low Power Brown Out Detect control:
0: When BOD is enable, the Brown Out detect is always turned on by no
rmal run
or Power Down mode.
1: When BOD is enable, the 1/16 time will be turned on Brown Out detect circuit
by Power Down mode. When uC is entry Power Do
wn mode, the BOD will enable
internal RC OSC (20KHz).
3 SRST
Software reset:
1: Reset the chip as if a hardware reset occurred.
SRST
require Timed Access procedure to write. The remaining bits have
unrestricted write accesses. Please refer TA register description.
n UVOTO n E
Preliminary N79E352/N79E352R Data Sheet
Publication Release Date: Jul, 29, 2009
- 31 - Revision A06
2~1 BOV.1~0
Brownout voltage selection bits, see below table.
BOV.1 BOV.0 Brownout Voltage
0 x Brownout voltage is 2.6V
1 0 Brownout voltage is 3.8V
1 1 Brownout voltage is 4.5V
These bits are initialized at all resets with the inverse values of bits CBOV.1-
0 in
config1.3-2 bits. User is able to re-configure these bits after reset.
0 BOS
Brownout Status bit(Read only)
0: VDD is above VBOR+
1: VDD is below VBOR-
CAPTURE CONTROL 0 REGISTER
Bit: 7 6 5 4 3 2 1 0
- - - - CCT0.1 CCT0.0 - -
Mnemonic: CAPCON0 Address: A3h
BIT NAME FUNCTION
7-4 - Reserved.
3-2 CCT0[1:0] Capture 0 edge select:
00 : Rising edge trigger.
01 : Falling edge trigger.
10 : Either rising or falling edge trigger.
11 : Reserved
1-0 - Reserved.
CAPTURE CONTROL 1 REGISTER
Bit: 7 6 5 4 3 2 1 0
0 T0CC - - ENF0 - - CPTF0
Mnemonic: CAPCON1 Address: A4h
BIT NAME FUNCTION
7 - Must be 0.
6 T0CC Timer 0 Clear Counter bit.
0: Timer 0 is not clear when input capture/cap sensor trigger.
1: Timer 0 will be cleared when input capture/cap sensor trigger.
5-4 - Reserved.
3 ENF0 Enable filter for capture input 0.
n UVOTO n = ia‘
Preliminary N79E352/N79E352R Data Sheet
- 32 -
2-1 - Reserved.
0 CPTF0 External input capture 0 interrupt flag. It can be cleared by software.
PORT 4
Bit:
7
6
5
4
3
2
1
0
-
-
-
-
P4.3
P4.2
P4.1
P4.0
Mnemonic: P4 Address: A5h
BIT NAME FUNCTION
7~4 - Reserved.
3~0 P4.3~0 Port 4 is a bi-directional I/O port with internal pull-ups. Port 4 can not use bit-
addressable instruction (SETB or CLR).
INTERRUPT ENABLE
Bit:
7
6
5
4
3
2
1
0
EA
-
ET2
ES
ET1
EX1
ET0
EX0
Mnemonic: IE Address: A8h
BIT NAME FUNCTION
7 EA Global enable. Enable/Disable all interrupts.
6 - Reserved.
5 ET2 Enable Timer 2 interrupt.
4 ES Enable Serial Port 0 interrupt.
3 ET1 Enable Timer 1 interrupt.
2 EX1 Enable external interrupt 1.
1 ET0 Enable Timer 0 interrupt.
0 EX0 Enable external interrupt 0.
SLAVE ADDRESS
Bit: 7 6 5 4 3 2 1 0
SADDR.7 SADDR.6 SADDR.5 SADDR.4 SADDR.3 SADDR.2 SADDR.1 SADDR.0
Mnemonic: SADDR Address: A9h
BIT NAME FUNCTION
7~0 SADDR
The SADDR should be programmed to the given or broadcast address for serial
port 0 to which the slave processor is designated.
PORT 3
Bit:
7
6
5
4
3
2
1
0
P3.7
P3.6
P3.5
P3.4
P3.3
P3.2
P3.1
P3.0
Mnemonic: P3 Address: B0h
n UVOTO n =
Preliminary N79E352/N79E352R Data Sheet
Publication Release Date: Jul, 29, 2009
- 33 - Revision A06
P3.7-0: General purpose Input/Output port. Most instructions will read the port pins in case of a port
read access, however in case of read-modify-write instructions, the port latch is read. These alternate
functions are described below:
BIT NAME FUNCTION
7 P3.7 /RD or I/O pin by alternative.
6 P3.6 /WR or I/O pin by alternative.
5 P3.5 T1 or I/O pin by alternative.
4 P3.4 T0 or I/O pin by alternative.
3 P3.3 /INT1 or I/O pin by alternative.
2 P3.2 /INT0 or I/O pin by alternative.
1 P3.1 TxD or I/O pin by alternative.
0 P3.0 RxD or I/O pin by alternative.
PORT 0 OUTPUT MODE 1
Bit:
7
6
5
4
3
2
1
0
P0M1.7
P0M1.6
P0M1.5
P0M1.4
P0M1.3
P0M1.2
P0M1.1
P0M1.0
Mnemonic: P0M1 Address: B1h
BIT NAME FUNCTION
7-0 P0M1 To control the output configuration of P0 bits [7:0]
PORT 0 OUTPUT MODE 2
Bit:
7
6
5
4
3
2
1
0
P0M2.7
P0M2.6
P0M2.5
P0M2.4
P0M2.3
P0M2.2
P0M2.1
P0M2.0
Mnemonic: P0M2 Address: B2h
BIT NAME FUNCTION
7-0 P0M2 To control the output configuration of P0 bits [7:0]
PORT 1 OUTPUT MODE 1
Bit: 7 6 5 4 3 2 1 0
P1M1.7 P1M1.6 P1M1.5 P1M1.4 P1M1.3 P1M1.2 P1M1.1 P1M1.0
Mnemonic: P1M1 Address: B3h
BIT NAME FUNCTION
7-0 P1M1 To control the output configuration of P1 bits [7:0].
PORT 1 OUTPUT MODE 2
Bit:
7
6
5
4
3
2
1
0
P1M2.7 P1M2.6 P1M2.5 P1M2.4 P1M2.3 P1M2.2 P1M2.1 P1M2.0
Mnemonic: P1M2 Address: B4h
n UVOTO n =
Preliminary N79E352/N79E352R Data Sheet
- 34 -
BIT NAME FUNCTION
7-0 P1M2 To control the output configuration of P1 bits [7:0].
PORT 2 OUTPUT MODE 1
Bit:
7
6
5
4
3
2
1
0
P2M1.7
P2M1.6
P2M1.5
P2M1.4
P2M1.3
P2M1.2
P2M1.1
P2M1.0
Mnemonic: P2M1 Address: B5h
BIT NAME FUNCTION
7-0 P2M1 To control the output configuration of P2 bits [7:0]
PORT 2 OUTPUT MODE 2
Bit:
7
6
5
4
3
2
1
0
P2M2.7
P2M2.6
P2M2.5
P2M2.4
P2M2.3
P2M2.2
P2M2.1
P2M2.0
Mnemonic: P2M2 Address: B6h
BIT NAME FUNCTION
7-0 P2M2 To control the output configuration of P2 bits [7:0]
INTERRUPT HIGH PRIORITY
Bit:
7
6
5
4
3
2
1
0
-
-
PT2H
PSH
PT1H
PX1H
PT0H
PX0H
Mnemonic: IP0H Address: B7h
BIT NAME FUNCTION
7~6 - Reserved.
5 PT2H 1: To set interrupt high priority of Timer 2 is highest priority level.
4 PSH 1: To set interrupt high priority of Serial port is highest priority level.
3 PT1H 1: Ro set interrupt high priority of Timer 1 is highest priority level.
2 PX1H 1: To set interrupt high priority of External interrupt 1 is highest priority level.
1 PT0H 1: To set interrupt high priority of Timer 0 is highest priority level.
0 PX0H 1: To set interrupt high priority of External interrupt 0 is highest priority level.
INTERRUPT PRIORITY 0
Bit: 7 6 5 4 3 2 1 0
-
-
PT2
PS
PT1
PX1
PT0
PX0
Mnemonic: IP0 Address: B8h
BIT NAME FUNCTION
7~6 - Reserved.
5 PT2 1: To set interrupt priority of Timer 2 is higher priority level.
4 PS 1: To set interrupt priority of Serial port is higher priority level.
n UVOTO n E
Preliminary N79E352/N79E352R Data Sheet
Publication Release Date: Jul, 29, 2009
- 35 - Revision A06
3 PT1 1: To set interrupt priority of Timer 1 is higher priority level.
2 PX1 1: To set interrupt priority of External interrupt 1 is higher priority level.
1 PT0 1: To set interrupt priority of Timer 0 is higher priority level.
0 PX0 1: To set interrupt priority of External interrupt 0 is higher priority level.
SLAVE ADDRESS MASK ENABLE
Bit: 7 6 5 4 3 2 1 0
SADEN.7 SADEN.6 SADEN.5 SADEN.4 SADEN.3 SADEN.2 SADEN.1 SADEN.0
Mnemonic: SADEN Address: B9h
BIT NAME FUNCTION
7~0 SADEN
This register enables the Automatic Address Recognition feature of the Serial port
0. When a bit in the SADEN is set to 1, the same bit location in SADDR will be
compared with the incoming serial data. When SADEN is
0, then the bit becomes
a "don't care" in the comparison. This register enables the Automatic Address
Recognition feature of the Serial port 0. When all the bits of SADEN are 0,
interrupt will occur for any incoming address.
I2C DATA REGISTER
Bit:
7
6
5
4
3
2
1
0
I2DAT.7
I2DAT.6
I2DAT.5
I2DAT.4
I2DAT.3
I2DAT.2
I2DAT.1
I2DAT.0
Mnemonic: I2DAT Address: BCh
BIT NAME FUNCTION
7-0 I2DAT.[7:0] The data register of I2C.
I2C STATUS REGISTER
Bit:
7
6
5
4
3
2
1
0
I2STATUS.7
I2STATUS.6
I2STATUS.5
I2STATUS.4
I2STATUS.3
-
-
-
Mnemonic: I2STATUS Address: BDh
BIT NAME FUNCTION
7-0 I2STATUS.[7:0]
The status register of I2C:
The three least significant bits are always 0. The five most significant bits
contain the status code. There are 23 possible status codes. When
I2STATUS contains F8H, no serial interrupt is requested. All other
I2STATUS values correspond to defined I2C states. When each of these
states is entered, a status interrupt is requested (SI = 1). A valid status
code is present in I2STATUS one machine cycle after SI is set by hardware
and is still present one machine cycle after SI has been reset by software.
In addition, states 00H stands for a Bus Error. A Bus Error occurs when a
START or STOP condition is present at an illegal position in the formation
frame. Example of illegal position are during the serial transfer of an
address byte, a data byte or an acknowledge bit.
I2C BAUD RATE CONTROL REGISTER
Bit:
7
6
5
4
3
2
1
0
n UVOTO n E
Preliminary N79E352/N79E352R Data Sheet
- 36 -
I2CLK.7
I2CLK.6
I2CLK.5
I2CLK.4
I2CLK.3
I2CLK.2
I2CLK.1
I2CLK.0
Mnemonic: I2CLK Address: BEh
BIT NAME FUNCTION
7-0 I2CLK.[7:0] The I2C clock rate bits.
I2C TIMER COUNTER REGISTER
Bit:
7
6
5
4
3
2
1
0
-
-
-
-
-
ENTI
DIV4
TIF
Mnemonic: I2TIMER Address: BFh
BIT NAME FUNCTION
7~3 - Reserved.
2 ENTI
Enable I2C 14-bits Timer Counter:
0: Disable 14-bits Timer Counter count.
1: Enable 14-bits Timer Counter count. After enable ENTI and ENSI, the 14-bit
counter will be counted. When SI flag of I2C is set, the counter will stop to
count and 14-bits Timer Counter will be cleared.
1 DIV4
I2C Timer Counter clock source divide function:
0: The 14-bits Timer Counter source clock is FCPU clock.
1: The 14-bits Timer Counter source clock is divided by 4.
0 TIF
The I2C Timer Counter count flag:
0: The 14-bits Timer Counter is not overflow.
1: The 14-bits Timer Counter is overflow. Before enable I2C Timer (both ENTI,
ENSI = [1,1]) the SI must be cleared. If I2C interrupt is enabled. The I2C
interrupt service routine will be executed. This bit is cleared by software.
I2C CONTROL REGISTER
Bit:
7
6
5
4
3
2
1
0
- ENSI STA STO SI AA -
-
Mnemonic: I2CON Address: C0h
BIT NAME FUNCTION
7 - Reserved.
6 ENSI
0: Disable I2C Serial Function. The SDA and SCL output are in a high
impedance state. SDA and SCL input signals are ignored, I2C is not in the
addressed slave mode or it is not addressable, and STO bit in I2CON is
forced to “0”. No other bits are affected. P1.3 (SCL) and P1.2 (SDA) may be
used as open drain I/O ports.
1: Enable I2C Serial Function. The P1.2 and P1.3 port latches must be to logic
1.
5 STA START flag:
0: The STA bit is reset, no START condition or repeated START condition will
n UVOTO n =
Preliminary N79E352/N79E352R Data Sheet
Publication Release Date: Jul, 29, 2009
- 37 - Revision A06
be generated.
1: The STA bit is set to enter a master mode. The I2C hardware checks the
status of I2C bus and generates a START condition if the bus is free. If bus is
not free, then I2C waits for a STOP condition and generates a START
condition after a delay. If STA is set while I2C is already in a master mode
and one or more bytes are transmitted or received, I2C transmits a repeated
START condition. STA may be set any time. STA may also be set when I2C
interface is an addressed slave mode.
4 STO
The bit STO bit is set while I2C is in a master mode. A STOP condition is
transmitted to the I2C bus. When the STOP condition is detected on the bus,
the I2C hardware clears the STO flag. In a slave mode, the STO flag may be
set to recover from a bus error condition. In this case, no STOP condition is
transmitted to the I2C bus. However, the I2C hardware behaves as if a STOP
condition has been received and it switches to the not addressable slave
receiver mode. The STO flag is automatically cleared by hardware. If the STA
and STO bits are both set, then a STOP condition is transmitted to the I2C bus
if I2C is in a master mode (in a slave mode, I2C generates an internal STOP
condition which is not transmitted). I2C then transmits a START condition.
3 SI
0: When the SI flag is reset, no serial interrupt is requested, and there is no
stretching on the serial clock on the SCL line.
1: When a new I2C bus state is present in the I2STATUS register, the SI flag is
set by hardware, and, if the EA and ES bits (in IE register) are both set, a
serial interrupt is requested when SI is set. The only state that does not
cause SI to be set is state F8H, which indicates that no relevant state
information is available. When SI is set, the low period of the serial clock on
the SCL line is stretched, and the serial transfer is suspended. A high level on
the SCL line is unaffected by the serial interrupt flag. SI must be cleared by
software.
2 AA
Assert Acknowledge Flag:
0:
A not acknowledge (high level to SDA) will be returned during the
acknowledge clock pulse on SCL when: 1) A data has been received while
I2C is in the master receiver mode. 2) A data byte has been received while
I2C is in the addressed slave receiver mode.
1: An acknowledge (low level to SDA) will be returned during the acknowledge
clock pulse on the SCL line when: 1) The own slave address has been
received. 2) A data byte has been received while I2C is in the master receiver
mode. 3) A data byte has been received while I2C is in the addressed slave
receiver mode. 4) The General Call address has been received while the
general call bit (GC) in I2ADDR is set.
1~0 - Reserved.
I2C ADDRESS REGISTER
Bit:
7
6
5
4
3
2
1
0
I2ADDR.7
I2ADDR.6
I2ADDR.5
I2ADDR.4
I2ADDR.3
I2ADDR.2
I2ADDR.1
GC
Mnemonic: I2ADDR Address: C1h
BIT NAME FUNCTION
n UVOTO n =
Preliminary N79E352/N79E352R Data Sheet
- 38 -
7~1 I2ADDR.[7:1]
I2C Address register:
The 8051 uC can read from and write to this 8-
bit, directly addressable
SFR. The content of this register is irrelevant when I2C is in master mode.
In the slave mode, the seven most significant bits must be loaded with the
MCU’s own address. The I2C hardware will react if either of the address is
matched.
0 GC
General Call Function.
0: Disable General Call Function.
1: Enable General Call Function.
ROMMAP
Bit:
7
6
5
4
3
2
1
0
WS
1
-
-
-
1
1
0
Mnemonic: ROMMAP Address: C2h
BIT NAME FUNCTION
7 WS Wait State Signal Enable. Setting this bit enables the
WAIT
signal on P4.0. The
device will sample the wait state control signal
WAIT
via P4.0 during MOVX
instruction. This bit is time access protected.
6~0 - Reserved.
TA REG C7H
ROMMAP REG C2H
CKCON REG 8EH
MOV TA,#AAH
MOV TA,#55H
ORL ROMMAP,#10000000B ; Set WS bit to enable wait signal.
POWER MANAGEMENT REGISTER
Bit:
7
6
5
4
3
2
1
0
CD1
CD0
SWB
-
-
ALE-OFF
-
-
Mnemonic: PMR Address: C4h
BIT NAME FUNCTION
n UVOTO n =
Preliminary N79E352/N79E352R Data Sheet
Publication Release Date: Jul, 29, 2009
- 39 - Revision A06
7~6 CD1~0
Clock Divide Control. These bit selects the number of
clocks required to
generate one machine cycle. There are three modes including divide by 4, 64 or
1024. Switching between modes must first go back devide by 4 mode. For
instance, to go from 64 to 1024 clocks/machine cycle the device must first go
from 64 to 4 clocks/machine cycle, and then from 4 to 1024 clocks/machine
cycle.
CD1, CD0 Clocks/machine Cycle
0 X 4
1 0 64
1 1 1024
5 SWB
Switchback Enable. Setting this bit allows an enabled external interrupt or serial
port/I2C activity to force the CD1, CD0 to divide by 4 state (0,X). The device will
switch modes at the start of the jump to interrupt service routine while an
external interrupt is enabled and actually recognized by microcontroller. While a
serial port/I2C reception, the switchback occurs at the start of the instruction
following the falling edge of the start bit. Note: Changing SWB bit is ignored
during serial port/I2C activities.
4~3 - Reserved.
2 ALE-0FF
This bit disables the expression of the ALE signal on the device pin during all on-
board program and data memory accesses. External memory acc
esses will
automatically enable ALE independent of ALE-OFF.
0 = ALE expression is enable.
1 = ALE expression is disable.
1~0 - Reserved.
STATUS
Bit:
7
6
5
4
3
2
1
0
-
-
-
-
-
-
SPTA0
SPRA0
Mnemonic: STATUS Address: C5h
BIT NAME FUNCTION
7-2 - Reserved.
1 SPTA0 Serial Port 0 Transmit Activity. This bit is set during serial port 0 is currently
transmitting data. It is cleared when TI bit is set by hardware. Changing the Clock
Divide Control bits CD0, CD1 will be ignored when this bit is set to 1 and SWB =
1.
0 SPRA0 Serial Port 0 Receive Activity. This bit is set during serial port 0 is currently
receiving a data. It is cleared when RI bit is set by hardware. Changing the Clock
Divide Control bits CD0, CD1 will be ignored when this bit is set to 1 and SWB =
1.
NVM LOW BYTE ADDRESS
Bit:
7
6
5
4
3
2
1
0
n UVOTO n E
Preliminary N79E352/N79E352R Data Sheet
- 40 -
-
NVMADD
R.6
NVMADD
R.5
NVMADD
R.4
NVMADD
R.3
NVMADD
R.2
NVMADD
R.1
NVMADD
R.0
Mnemonic: NVMADDR Address: C6h
BIT NAME FUNCTION
7 - Reserved
6~0 NVMADDR.[6:0] The NVM address:
The register indicates NVM data memory address on On-
Chip code
memory space.
TIMED ACCESS
Bit:
7
6
5
4
3
2
1
0
TA.7
TA.6
TA.5
TA.4
TA.3
TA.2
TA.1
TA.0
Mnemonic: TA Address: C7h
BIT NAME FUNCTION
7-0 TA.[7:0]
The Timed Access register:
The Timed Access register controls the access to protected bits. To access
protected bits, the user must first write AAH to the TA. This must be immediately
followed by a write of 55H to TA. Now a window is opened in the protected bits
for three machine cycles, during which the user can write to these bits.
TIMER 2 CONTROL
Bit:
7
6
5
4
3
2
1
0
TF2 EXF2 RCLK TCLK EXEN2 TR2
C T/ 2
CP RL/ 2
Mnemonic: T2CON Address: C8h
BIT NAME FUNCTION
7 TF2
Timer 2 overflow flag:
Timer 2 overflow flag: This bit is set when Timer 2 overflows. It is also set when
the count is equal to the capture register in down count mode. It can be set only
if RCLK and TCLK are both 0. It is cleared only by software. Software can also
set or clear this bit.
6 EXF2
Timer 2 External Flag: A negative transition on the T2EX pin (P1.1) or timer 2
overflow will cause this flag to set based on the
CP RL/ 2
, EXEN2 and DCEN
bits. If set by a negative transition, this flag must be cleared by software. Setting
this bit in software or detection of a negative transition on T2EX pin will force a
timer interrupt if enabled.
5 RCLK
Receive Clock Flag: This bit determines the serial port time-base when receiving
data in serial modes 1 or 3. If it is 0, then timer 1 overflow is used for baud rate
generation, otherwise timer 2 overflow is used. Setting this bit forces timer 2 in
baud rate generator mode.
n UVOTO n E oum
Preliminary N79E352/N79E352R Data Sheet
Publication Release Date: Jul, 29, 2009
- 41 - Revision A06
4 TCLK
Transmit Clock Flag: This bit determines the serial port time-base when
transmitting data in modes 1 and 3. If it is set to 0, the timer 1 overflow is used
to generate the baud rate clock otherwise timer 2 overflow is used. Setting this
bit forces timer 2 in baud rate generator mode.
3 EXEN2
Timer 2 External Enable. This bit enables the capture/reload function on the
T2EX pin if Timer 2 is not generating baud clocks for the serial port. If this bit is
0, then the T2EX pin will be ignored, otherwise a negative transition detected on
the T2EX pin will result in capture or reload.
2 TR2
Timer 2 Run Control:
This bit enables/disables the operation of timer 2. Halting this will preserve the
current count in TH2, TL2.
1
2T/C
Counter/Timer Select. This bit determines whether timer 2 will function as a timer
or a counter. Independent of this bit, the timer will run at 2 clocks per tick w
hen
used in baud rate generator
mode. If it is set to 0, then timer 2 operates as a
timer at a speed depending on T2M bit
(CKCON.5), otherwise it will count
negative edges on T2 pin.
0
2RL/CP
Compare/Reload Select:
This bit determines whether the capture or reload function will be used for timer
2. If either RCLK or TCLK is set, this bit will be ignored and the timer will function
in an auto-reload mode following each overflow. If the bit is 0 then auto-reload
will occur when timer 2 overflows or a falling edge is detected on T2EX pin if
EXEN2 = 1. If this bit is 1, then timer 2 captures will occur when a falling edge is
detected on T2EX pin if EXEN2 = 1.
TIMER 2 MODE CONTROL
Bit:
7
6
5
4
3
2
1
0
-
-
-
ICEN0
T2CR
1
T2OE
DCEN
Mnemonic: T2MOD Address: C9h
BIT NAME FUNCTION
7~5 - Reserved.
4 ICEN0 External input capture 0 enable:
This bit enables input capture 0 on T0 pin.
3 T2CR
Timer 2 Capture Reset:
In the Timer 2 Capture Mode this bit enables/disables hardware automatically
reset timer 2 while the value in TL2 and TH2 have been transferred into the
capture register.
2 - Must be 1.
1 T2OE Timer 2 Output Enable. This bit enables/disables the Timer 2 clock out function.
0 DCEN Down Count Enable: This bit, in conjunction with the T2EX pin, controls the
direction that timer 2 counts in 16-bit auto-reload mode.
TIMER 2 CAPTURE LSB
Bit:
7
6
5
4
3
2
1
0
RCAP2L.
RCAP2L.
RCAP2L.
RCAP2L.
RCAP2L.
RCAP2L.
RCAP2L.
RCAP2L.
n UVOTO n =
Preliminary N79E352/N79E352R Data Sheet
- 42 -
7
6
5
4
3
2
1
0
Mnemonic: RCAP2L Address: CAh
BIT NAME FUNCTION
7-0 RCAP2L
Timer 2 Capture LSB:
This register is used to capture the TL2 value when a timer 2 is configured in
capture mode.RCAP2L is also used as the LSB of a 16-bit reload value when
timer 2 is configured in auto-reload mode.
n UVOTO n =
Preliminary N79E352/N79E352R Data Sheet
Publication Release Date: Jul, 29, 2009
- 43 - Revision A06
TIMER 2 CAPTURE MSB
Bit:
7
6
5
4
3
2
1
0
RCAP2H.
7
RCAP2H.
6
RCAP2H.
5
RCAP2H.
4
RCAP2H.
3
RCAP2H.
2
RCAP2H.
1
RCAP2H.
0
Mnemonic: RCAP2H Address: CBh
BIT NAME FUNCTION
7-0 RCAP2H
Timer 2 Capture MSB:
This register is used to capture the TH2 value when a timer 2 is configured in
capture mode. RCAP2H is also used as the MSB of a 16-bit reload value when
timer 2 is configured in auto-reload mode.
TIMER 2 LSB
Bit: 7 6 5 4 3 2 1 0
TL2.7 TL2.6 TL2.5 TL2.4 TL2.3 TL2.2 TL2.1 TL2.0
Mnemonic: TL2 Address: CCh
BIT NAME FUNCTION
7-0 TL2 Timer 2 LSB.
TIMER 2 MSB
Bit:
7
6
5
4
3
2
1
0
TH2.7
TH2.6
TH2.5
TH2.4
TH2.3
TH2.2
TH2.1
TH2.0
Mnemonic: TH2 Address: CDh
BIT NAME FUNCTION
7-0 TL2 Timer 2 LSB.
NVM CONTROL
Bit:
7
6
5
4
3
2
1
0
EER
EWR
EnNVM
-
-
-
-
-
Mnemonic: NVMCON Address: CEh
BIT NAME FUNCTION
7 EER NVM page(n) erase bit:
0: Without erase NVM page(n).
1: Set this bit to erase page(n) of NVM. The NVM has 8 pages and each page
have 16 bytes data memory. Initiate page select by programming NVMADDL
registers, which will automatically enable page area. When user set this bit,
the page erase process will begin and program counter will halt at this
instruction. After the erase process is completed
, program counter will
continue executing next instruction.
6 EWR NVM data write bit:
0: Without write NVM data.
n UVOTO n E RS.1-0: Register Bank Selection BHs:
Preliminary N79E352/N79E352R Data Sheet
- 44 -
1: Set this bit to write NVM bytes and program counter will halt at this instruction.
After write is finished, program counter will kept next instruction then
executed.
5 EnNVM To enable read NVM data memory area.
0: To disable the MOVX instruction to read NVM data memory.
1: To enable the MOVX instruction to read NVM data memory, the External RAM
or AUX-RAM will be disabled.
4-0 - Reserved
NVM DATA
Bit:
7
6
5
4
3
2
1
0
NVMDAT.
7
NVMDAT.
6
NVMDAT.
5
NVMDAT.
4
NVMDAT
3
NVMDAT.
2
NVMDAT.
1
NVMDAT.
0
Mnemonic: NVMDATA Address: CFh
BIT NAME FUNCTION
7~0 NVMDAT.[7:0] The NVM data write register. The read NVM data is by MOVC instruction.
PROGRAM STATUS WORD
Bit:
7
6
5
4
3
2
1
0
CY
AC
F0
RS1
RS0
OV
F1
P
Mnemonic: PSW Address: D0h
BIT NAME FUNCTION
7 CY
Carry flag:
Set for an arithmetic operation which results in a carry being generated from the
ALU. It is also used as the accumulator for the bit operations.
6
AC Auxiliary carry:
Set when the previous operation resulted in a carry from the high order nibble.
5 F0 User flag 0:
The General purpose flag that can be set or cleared by the user.
4~3 RS1~RS0 Register bank select bits.
2 OV
Overflow flag:
Set when a carry was generated from the seventh bit but not from the 8th bit as
a result of the previous operation, or vice-versa.
1 F1 User Flag 1:
The General purpose flag that can be set or cleared by the user software.
0 P Parity flag:
Set/cleared by hardware to indicate odd/even number of 1's in the accumulator.
RS.1-0: Register Bank Selection Bits:
n UVOTO n =
Preliminary N79E352/N79E352R Data Sheet
Publication Release Date: Jul, 29, 2009
- 45 - Revision A06
RS1 RS0 REGISTER BANK ADDRESS
0
0
0
00-07h
0
1
1
08-0Fh
1
0
2
10-17h
1
1
3
18-1Fh
PWM CONTROL REGISTER 3
Bit:
7
6
5
4
3
2
1
0
- - PWM1OE PWM0OE PCLK.1 PCLK.0 FP1 FP0
Mnemonic: PWMCON3 Address: D7h
BIT NAME FUNCTION
7~6 - Reserved.
5 PWM1OE
PWM1 output enable bit.
0: PWM1 output disabled.
1: PWM1 output enabled.
4 PWM0OE
PWM0 output enable bit.
0: PWM0 output disabled.
1: PWM0 output enabled.
3~2 PCLK.1~0
PWM clock source selection bits, see below table.
PCLK[1:0] PWM clock source
00 Fosc
01 Timer 0 overflow
10 Timer 1 overflow
11 Reserved
1~0 FP1~0
Select PWM frequency pre-scale select bits, see belowtable.
FP[1:0] Fpwm
00 FPCLK/1 (default)
01 FPCLK/2
10 FPCLK/4
11 FPCLK/8
WATCHDOG CONTROL
Bit: 7 6 5 4 3 2 1 0
WDRUN POR - - WDIF WTRF EWRST WDCLR
Mnemonic: WDCON Address: D8h
BIT NAME FUNCTION
n UVOTO n =
Preliminary N79E352/N79E352R Data Sheet
- 46 -
7 WDRUN 0: The Watchdog is stopped.
1: The Watchdog is running.
6 POR Power-
on reset flag. Hardware will set this flag on a power up condition. This flag
can be read or
written by software. A write by software is the only way to clear
this bit once it is set.
5~4 - Reserved.
3 WDIF
Watchdog Timer Interrupt flag:
0: If the interrupt is not enabled, then this bit indicates that the time-out period
has elapsed. This bit must be cleared by software.
1: If the watchdog interrupt is enabled, hardware will set this bit to indicate that
the watchdog interrupt has occurred.
2 WTRF
Watchdog Timer Reset flag:
1: Hardware will set this bit when the watchdog timer causes a reset. Software
can read it but must clear it manually. A power-fail reset will also clear the bit.
This bit helps software in determining the cause of a reset. If EWRST = 0,
the watchdog timer will have no affect on this bit.
1 EWRST 0: Disable Watchdog Timer Reset.
1: Enable Watchdog Timer Reset.
0 WDCLR
Reset Watchdog Timer:
This bit helps in putting the watchdog timer into a know state. It also helps in
resetting the watchdog timer before a time-out occurs. Failing to set the EWRST
before time-out will cause an interrupt (if EWDI (EIE.4) is set), and 512 clocks
after that a watchdog timer reset will be generated (if EWRST is set). This bit is
self-clearing by hardware.
The WDCON SFR is set to a 01xx0000B on a power-on-reset. WTRF (WDCON.2) is set to a 1 on a
Watchdog timer reset, but to a 0 on power on/down resets. WTRF (WDCON.2) is not altered by an
external reset. EWRST (WDCON.1) is set to 0 on all resets.
All the bits in this SFR have unrestricted read access. WDRUN, POR, EWRST, WDIF and WDCLR
require Timed Access procedure to write. The remaining bits have unrestricted write accesses. Please
refer TA register description.
TA REG C7H
WDCON REG D8H
MOV TA, #AAH ; To access protected bits
MOV TA, #55H
SETB WDCON.0 ; Reset watchdog timer
ORL WDCON, #00110000B ; Select 26 bits watchdog timer
MOV TA, #AAH
MOV TA, #55H
ORL WDCON, #10000010B ; Enable watchdog
PWM 0 LOW BITS REGISTER
Bit:
7
6
5
4
3
2
1
0
n UVOTO n =
Preliminary N79E352/N79E352R Data Sheet
Publication Release Date: Jul, 29, 2009
- 47 - Revision A06
PWM0.7
PWM0.6
PWM0.5
PWM0.4
PWM0.3
PWM0.2
PWM0.1
PWM0.0
Mnemonic: PWM0L Address: DAh
BIT NAME FUNCTION
7~0 PWM0 PWM 0 Low Bits Register.
PWM 0 LOW BITS REGISTER
Bit:
7
6
5
4
3
2
1
0
PWM1.7
PWM1.6
PWM1.5
PWM1.4
PWM1.3
PWM1.2
PWM1.1
PWM1.0
Mnemonic: PWM1L Address: DBh
BIT NAME FUNCTION
7~0 PWM1 PWM 1 Low Bits Register.
PWM CONTROL REGISTER 1
Bit:
7
6
5
4
3
2
1
0
PWMRUN
-
-
CLRPWM
-
-
-
-
Mnemonic: PWMCON1 Address: DCh
BIT NAME FUNCTION
7 PWMRUN
0: The PWM is not running.
1: The PWM counter is running.
6~5 - Reserved.
4 CLRPWM 1: Clear 8-bit PWM counter to 000H.
It is automatically cleared by hardware.
3~0 - Reserved.
ACCUMULATOR
Bit: 7 6 5 4 3 2 1 0
ACC.7 ACC.6 ACC.5 ACC.4 ACC.3 ACC.2 ACC.1 ACC.0
Mnemonic: ACC Address: E0h
BIT NAME FUNCTION
7-0 ACC The A or ACC register is the standard 8052 accumulator.
INPUT CAPTURE 0 LOW REGISTER
Bit: 7 6 5 4 3 2 1 0
CCL0.7 CCL0.6 CCL0.5 CCL0.4 CCL0.3 CCL0.2 CCL0.1 CCL0.0
Mnemonic: CCL0 Address: E4h
BIT NAME FUNCTION
7-0 CCL0 Capture 0 low byte.
n UVOTO n E
Preliminary N79E352/N79E352R Data Sheet
- 48 -
INPUT CAPTURE 0 HIGH REGISTER
Bit: 7 6 5 4 3 2 1 0
CCH0.7 CCH0.6 CCH0.5 CCH0.4 CCH0.3 CCH0.2 CCH0.1 CCH0.0
Mnemonic: CCH0 Address: E4h
BIT NAME FUNCTION
7-0 CCH0 Capture 0 high byte.
IINTERRUPT ENABLE REGISTER 1
Bit:
7
6
5
4
3
2
1
0
ECPTF
EBO
-
EWDI
-
-
EKB
EI2
Mnemonic: EIE Address: E8h
BIT NAME FUNCTION
7 ECPTF 0: Disable capture interrupt.
1: Enable capture interrupt.
6 EBO
Enable brownout interrupt.
0: Disable brownout interrupt.
1: Enable brownout interrupt.
5 - Reserved.
4 EWDI 0: Disable Watchdog Timer Interrupt.
1: Enable Watchdog Timer Interrupt.
3~2 - Reserved.
1 EKB 0: Disable Keypad Interrupt.
1: Enable Keypad Interrupt.
0 EI2 0: Disable I2C Interrupt.
1: Enable I2C Interrupt.
KEYBOARD LEVEL
Bit:
7
6
5
4
3
2
1
0
KBL.7
KBL.6
KBL.5
KBL.4
KBL.3
KBL.2
KBL.1
KBL.0
Mnemonic: KBL Address: E9h
BIT NAME FUNCTION
7~0 KBL.7~0
Keyboard trigger level.
0: Low level trigger.x pin.
1: High level trigger on KBI.x pin.
[x = 0-7]
PORTS SHMITT REGISTER
Bit: 7 6 5 4 3 2 1 0
n UVOTO n
Preliminary N79E352/N79E352R Data Sheet
Publication Release Date: Jul, 29, 2009
- 49 - Revision A06
-
-
P5S
-
P3S
P2S
P1S
P0S
Mnemonic: PORTS Address: ECh
BIT NAME FUNCTION
7~6 - Reserved.
5 P5S 1: Enables Schmitt trigger inputs on Port 5.
4 - Reserved.
3 P3S 1: Enables Schmitt trigger inputs on Port 3.
2 P2S 1: Enables Schmitt trigger inputs on Port 2.
1 P1S 1: Enables Schmitt trigger inputs on Port 1.
0 P0S 1: Enables Schmitt trigger inputs on Port 0.
PORT 5 OUTPUT MODE 1
Bit:
7
6
5
4
3
2
1
0
-
-
-
-
-
ENCLK
P5M1.1
P5M1.0
Mnemonic: P5M1 Address: EDh
BIT NAME FUNCTION
7~3 - Reserved.
2 ENCLK 1: Enabled clock output to XTAL2 pin (P5.0).
1~0 P5M1.1~0 To control the output configuration of P5 bits [1:0].
PORT 5 OUTPUT MODE 2
Bit: 7 6 5 4 3 2 1 0
- - - - - - P5M2.1 P5M2.0
Mnemonic: P5M2 Address: EEh
BIT NAME FUNCTION
7~2 - Reserved.
1~0 P5M2.1~0 To control the output configuration of P5 bits [1:0].
B REGISTER
Bit:
7
6
5
4
3
2
1
0
B.7
B.6
B.5
B.4
B.3
B.2
B.1
B.0
Mnemonic: B Address: F0h
BIT NAME FUNCTION
7-0 B
The B register is the standard 8052 register that serves as a second
accumulator.
INTERRUPT HIGH PRIORITY 1
Bit:
7
6
5
4
3
2
1
0
n UVOTO n
Preliminary N79E352/N79E352R Data Sheet
- 50 -
PCAPH
PBOH
-
PWDIH
-
-
PKBH
PI2H
Mnemonic: IP1H Address: F7h
BIT NAME FUNCTION
7 PCAPH 1: To set interrupt high priority of Input Capture 0 as highest priority level.
6 PBOH 1: To set interrupt high priority of Brownout is highest priority level.
5 - Reserved.
4 PWDIH 1: To set interrupt high priority of Watchdog is highest priority level.
3~2 - Reserved.
1 PKBH 1: To set interrupt high priority of Keypad is highest priority level.
0 PI2H 1: To set interrupt high priority of I2C is highest priority level.
INTERRUPT PRIORITY 1
Bit:
7
6
5
4
3
2
1
0
PCAP
PBO
-
PWDI
-
-
PKB
PI2
Mnemonic: IP1 Address: F8h
BIT NAME FUNCTION
7 PCAP 1: To set interrupt priority of Input Capture 0 as higher priority level.
6 PBO 1: To set interrupt priority of Brownout is higher priority level.
5 - Reserved.
4 PWDI 1: To set interrupt priority of Watchdog is higher priority level.
3~2 - Reserved.
1 PKB 1: To set interrupt priority of Keypad is higher priority level.
0 PI2 1: To set interrupt priority of I2C is higher priority level.
n UVOTO n =
Preliminary N79E352/N79E352R Data Sheet
Publication Release Date: Jul, 29, 2009
- 51 - Revision A06
9. INSTRUCTION
The N79E352(R) executes all the instructions of the standard 8052 family. The operation of these
instructions, their effect on the flag bits and the status bits is exactly the same. However, timing of
these instructions is different. The reason for this is two fold. Firstly, in the N79E352(R), each machine
cycle consists of 4 clock periods, while in the standard 8052 it consists of 12 clock periods. Also, in the
N79E352(R) there is only one fetch per machine cycle i.e. 4 clocks per fetch, while in the standard
8052 there can be two fetches per machine cycle, which works out to 6 clocks per fetch.
The advantage the N79E352(R) has is that since there is only one fetch per machine cycle, the number
of machine cycles in most cases is equal to the number of operands that the instruction has. In case of
jumps and calls there will be an additional cycle that will be needed to calculate the new address. But
overall the N79E352(R) reduces the number of dummy fetches and wasted cycles, thereby improving
efficiency as compared to the standard 8052.
Table 9-1: Instructions that affect Flag settings
Instruction Carry Overflow Auxiliary
Carry Instruction Carry Overflow Auxiliary
Carry
ADD X X X CLR C 0
ADDC X X X CPL C X
SUBB X X X ANL C, bit X
MUL 0 X ANL C, bit X
DIV 0 X ORL C, bit X
DA A X ORL C, bit X
RRC A X MOV C, bit X
RLC A X CJNE X
SETB C 1
A "X" indicates that the modification is as per the result of instruction.
n UVOTO n =
Preliminary N79E352/N79E352R Data Sheet
- 52 -
Table 9-2: Instruction Timing for N79E352(R)
Instruction HEX
Op-Code Bytes N79E352(R)
Machine
Cycles
N79E352(R)
Clock
Cycles
8052
Clock
Cycles
N79E352(R) vs.
8052 Speed
Ratio
NOP 00 1 1 4 12 3
ADD A, R0 28 1 1 4 12 3
ADD A, R1 29 1 1 4 12 3
ADD A, R2 2A 1 1 4 12 3
ADD A, R3 2B 1 1 4 12 3
ADD A, R4 2C 1 1 4 12 3
ADD A, R5 2D 1 1 4 12 3
ADD A, R6 2E 1 1 4 12 3
ADD A, R7 2F 1 1 4 12 3
ADD A, @R0 26 1 1 4 12 3
ADD A, @R1 27 1 1 4 12 3
ADD A, direct 25 2 2 8 12 1.5
ADD A, #data 24 2 2 8 12 1.5
n UVOTO n =
Preliminary N79E352/N79E352R Data Sheet
Publication Release Date: Jul, 29, 2009
- 53 - Revision A06
Instruction Timing for N79E352(R), continued
Instruction HEX
Op-Code Bytes N79E352(R)
Machine
Cycles
N79E352(R)
Clock
Cycles
8052
Clock
Cycles
N79E352(R) vs.
8052 Speed
Ratio
ADDC A, R0 38 1 1 4 12 3
ADDC A, R1 39 1 1 4 12 3
ADDC A, R2 3A 1 1 4 12 3
ADDC A, R3 3B 1 1 4 12 3
ADDC A, R4 3C 1 1 4 12 3
ADDC A, R5 3D 1 1 4 12 3
ADDC A, R6 3E 1 1 4 12 3
ADDC A, R7 3F 1 1 4 12 3
ADDC A, @R0 36 1 1 4 12 3
ADDC A, @R1 37 1 1 4 12 3
ADDC A, direct 35 2 2 8 12 1.5
ADDC A, #data 34 2 2 8 12 1.5
ACALL addr11 71, 91, B1, 11,
31, 51, D1, F1 2 3 12 24 2
AJMP ADDR11 01, 21, 41, 61,
81, A1, C1, E1 2 3 12 24 2
ANL A, R0 58 1 1 4 12 3
ANL A, R1 59 1 1 4 12 3
ANL A, R2 5A 1 1 4 12 3
ANL A, R3 5B 1 1 4 12 3
ANL A, R4 5C 1 1 4 12 3
ANL A, R5 5D 1 1 4 12 3
ANL A, R6 5E 1 1 4 12 3
ANL A, R7 5F 1 1 4 12 3
ANL A, @R0 56 1 1 4 12 3
ANL A, @R1 57 1 1 4 12 3
ANL A, direct 55 2 2 8 12 1.5
ANL A, #data 54 2 2 8 12 1.5
ANL direct, A 52 2 2 8 12 1.5
ANL direct, #data 53 3 3 12 24 2
ANL C, bit 82 2 2 8 24 3
ANL C, /bit B0 2 2 8 24 3
CJNE A, direct, rel B5 3 4 16 24 1.5
CJNE A, #data, rel B4 3 4 16 24 1.5
CJNE @R0, #data, rel B6 3 4 16 24 1.5
CJNE @R1, #data, rel B7 3 4 16 24 1.5
CJNE R0, #data, rel B8 3 4 16 24 1.5
CJNE R1, #data, rel B9 3 4 16 24 1.5
CJNE R2, #data, rel BA 3 4 16 24 1.5
CJNE R3, #data, rel BB 3 4 16 24 1.5
CJNE R4, #data, rel BC 3 4 16 24 1.5
CJNE R5, #data, rel BD 3 4 16 24 1.5
CJNE R6, #data, rel BE 3 4 16 24 1.5
n UVOTO n =
Preliminary N79E352/N79E352R Data Sheet
- 54 -
Instruction Timing for N79E352(R), continued
Instruction HEX
Op-Code Bytes N79E352(R)
Machine
Cycles
N79E352(R)
Clock
Cycles
8052
Clock
Cycles
N79E352(R) vs.
8052 Speed
Ratio
CLR A E4 1 1 4 12 3
CPL A F4 1 1 4 12 3
CLR C C3 1 1 4 12 3
CLR bit C2 2 2 8 12 1.5
CPL C B3 1 1 4 12 3
CPL bit B2 2 2 8 12 1.5
DEC A 14 1 1 4 12 3
DEC R0 18 1 1 4 12 3
DEC R1 19 1 1 4 12 3
DEC R2 1A 1 1 4 12 3
DEC R3 1B 1 1 4 12 3
DEC R4 1C 1 1 4 12 3
DEC R5 1D 1 1 4 12 3
DEC R6 1E 1 1 4 12 3
DEC R7 1F 1 1 4 12 3
DEC @R0 16 1 1 4 12 3
DEC @R1 17 1 1 4 12 3
DEC direct 15 2 2 8 12 1.5
DEC DPTR A5 1 2 8 - -
DIV AB 84 1 5 20 48 2.4
DA A D4 1 1 4 12 3
DJNZ R0, rel D8 2 3 12 24 2
DJNZ R1, rel D9 2 3 12 24 2
DJNZ R5, rel DD 2 3 12 24 2
DJNZ R2, rel DA 2 3 12 24 2
DJNZ R3, rel DB 2 3 12 24 2
DJNZ R4, rel DC 2 3 12 24 2
DJNZ R6, rel DE 2 3 12 24 2
DJNZ R7, rel DF 2 3 12 24 2
DJNZ direct, rel D5 3 4 16 24 1.5
INC A 04 1 1 4 12 3
INC R0 08 1 1 4 12 3
INC R1 09 1 1 4 12 3
INC R2 0A 1 1 4 12 3
INC R3 0B 1 1 4 12 3
INC R4 0C 1 1 4 12 3
n UVOTO n =
Preliminary N79E352/N79E352R Data Sheet
Publication Release Date: Jul, 29, 2009
- 55 - Revision A06
Instruction Timing for N79E352(R), continued
Instruction HEX
Op-Code Bytes N79E352(R)
Machine
Cycles
N79E352(R)
Clock
Cycles
8052
Clock
Cycles
N79E352(R) vs.
8052 Speed
Ratio
INC R6 0E 1 1 4 12 3
INC R7 0F 1 1 4 12 3
INC @R0 06 1 1 4 12 3
INC @R1 07 1 1 4 12 3
INC direct 05 2 2 8 12 1.5
INC DPTR A3 1 2 8 24 3
JMP @A+DPTR 73 1 2 8 24 3
JZ rel 60 2 3 12 24 2
JNZ rel 70 2 3 12 24 2
JC rel 40 2 3 12 24 2
JNC rel 50 2 3 12 24 2
JB bit, rel 20 3 4 16 24 1.5
JNB bit, rel 30 3 4 16 24 1.5
JBC bit, rel 10 3 4 16 24 1.5
LCALL addr16 12 3 4 16 24 1.5
LJMP addr16 02 3 4 16 24 1.5
MUL AB A4 1 5 20 48 2.4
MOV A, R0 E8 1 1 4 12 3
MOV A, R1 E9 1 1 4 12 3
MOV A, R2 EA 1 1 4 12 3
MOV A, R3 EB 1 1 4 12 3
MOV A, R4 EC 1 1 4 12 3
MOV A, R5 ED 1 1 4 12 3
MOV A, R6 EE 1 1 4 12 3
MOV A, R7 EF 1 1 4 12 3
MOV A, @R0 E6 1 1 4 12 3
MOV A, @R1 E7 1 1 4 12 3
MOV A, direct E5 2 2 8 12 1.5
MOV A, #data 74 2 2 8 12 1.5
MOV R0, A F8 1 1 4 12 3
MOV R1, A F9 1 1 4 12 3
MOV R2, A FA 1 1 4 12 3
MOV R3, A FB 1 1 4 12 3
MOV R4, A FC 1 1 4 12 3
MOV R5, A FD 1 1 4 12 3
MOV R6, A FE 1 1 4 12 3
MOV R7, A FF 1 1 4 12 3
n UVOTO n =
Preliminary N79E352/N79E352R Data Sheet
- 56 -
Instruction Timing for N79E352(R), continued
Instruction HEX
Op-Code Bytes N79E352(R)
Machine
Cycles
N79E352(R)
Clock
Cycles
8052
Clock
Cycles
N79E352(R) vs.
8052 Speed
Ratio
MOV R1, direct A9 2 2 8 12 1.5
MOV R2, direct AA 2 2 8 12 1.5
MOV R3, direct AB 2 2 8 12 1.5
MOV R4, direct AC 2 2 8 12 1.5
MOV R5, direct AD 2 2 8 12 1.5
MOV R6, direct AE 2 2 8 12 1.5
MOV R7, direct AF 2 2 8 12 1.5
MOV R0, #data 78 2 2 8 12 1.5
MOV R1, #data 79 2 2 8 12 1.5
MOV R2, #data 7A 2 2 8 12 1.5
MOV R3, #data 7B 2 2 8 12 1.5
MOV R4, #data 7C 2 2 8 12 1.5
MOV R5, #data 7D 2 2 8 12 1.5
MOV R6, #data 7E 2 2 8 12 1.5
MOV R7, #data 7F 2 2 8 12 1.5
MOV @R0, A F6 1 1 4 12 3
MOV @R1, A F7 1 1 4 12 3
MOV @R0, direct A6 2 2 8 12 1.5
MOV @R1, direct A7 2 2 8 12 1.5
MOV @R0, #data 76 2 2 8 12 1.5
MOV @R1, #data 77 2 2 8 12 1.5
MOV direct, A F5 2 2 8 12 1.5
MOV direct, R0 88 2 2 8 12 1.5
MOV direct, R1 89 2 2 8 12 1.5
MOV direct, R2 8A 2 2 8 12 1.5
MOV direct, R3 8B 2 2 8 12 1.5
MOV direct, R4 8C 2 2 8 12 1.5
MOV direct, R5 8D 2 2 8 12 1.5
MOV direct, R6 8E 2 2 8 12 1.5
MOV direct, R7 8F 2 2 8 12 1.5
MOV direct, @R0 86 2 2 8 12 1.5
MOV direct, @R1 87 2 2 8 12 1.5
MOV direct, direct 85 3 3 12 24 2
MOV direct, #data 75 3 3 12 24 2
MOV DPTR, #data 16 90 3 3 12 24 2
MOVC A, @A+DPTR 93 1 2 8 24 3
n UVOTO n =
Preliminary N79E352/N79E352R Data Sheet
Publication Release Date: Jul, 29, 2009
- 57 - Revision A06
Instruction Timing for N79E352(R), continued
Instruction HEX
Op-Code Bytes N79E352(R)
Machine
Cycles
N79E352(R)
Clock
Cycles
8052
Clock
Cycles
N79E352(R) vs.
8052 Speed
Ratio
MOVX A, @R0 E2 1 2 - 9 8 - 36 24 3 - 0.66
MOVX A, @R1 E3 1 2 - 9 8 - 36 24 3 - 0.66
MOVX A, @DPTR E0 1 2 - 9 8 - 36 24 3 - 0.66
MOVX @R0, A F2 1 2 - 9 8 - 36 24 3 - 0.66
MOVX @R1, A F3 1 2 - 9 8 - 36 24 3 - 0.66
MOVX @DPTR, A F0 1 2 - 9 8 - 36 24 3 - 0.66
MOV C, bit A2 2 2 8 12 1.5
MOV bit, C 92 2 2 8 24 3
ORL A, R0 48 1 1 4 12 3
ORL A, R1 49 1 1 4 12 3
ORL A, R2 4A 1 1 4 12 3
ORL A, R3 4B 1 1 4 12 3
ORL A, R4 4C 1 1 4 12 3
ORL A, R5 4D 1 1 4 12 3
ORL A, R6 4E 1 1 4 12 3
ORL A, R7 4F 1 1 4 12 3
ORL A, @R0 46 1 1 4 12 3
ORL A, @R1 47 1 1 4 12 3
ORL A, direct 45 2 2 8 12 1.5
ORL A, #data 44 2 2 8 12 1.5
ORL direct, A 42 2 2 8 12 1.5
ORL direct, #data 43 3 3 12 24 2
ORL C, bit 72 2 2 8 24 3
ORL C, /bit A0 2 2 6 24 3
PUSH direct C0 2 2 8 24 3
POP direct D0 2 2 8 24 3
RET 22 1 2 8 24 3
RETI 32 1 2 8 24 3
RL A 23 1 1 4 12 3
RLC A 33 1 1 4 12 3
RR A 03 1 1 4 12 3
RRC A 13 1 1 4 12 3
SETB C D3 1 1 4 12 3
SETB bit D2 2 2 8 12 1.5
SWAP A C4 1 1 4 12 3
SJMP rel 80 2 3 12 24 2
SUBB A, R0 98 1 1 4 12 3
n UVOTO n =
Preliminary N79E352/N79E352R Data Sheet
- 58 -
Instruction Timing for N79E352(R), continued
Instruction HEX
Op-Code Bytes N79E352(R)
Machine
Cycles
N79E352(R)
Clock
Cycles
8052
Clock
Cycles
N79E352(R) vs.
8052 Speed
Ratio
SUBB A, R2 9A 1 1 4 12 3
SUBB A, R3 9B 1 1 4 12 3
SUBB A, R4 9C 1 1 4 12 3
SUBB A, R5 9D 1 1 4 12 3
SUBB A, R6 9E 1 1 4 12 3
SUBB A, R7 9F 1 1 4 12 3
SUBB A, @R0 96 1 1 4 12 3
SUBB A, @R1 97 1 1 4 12 3
SUBB A, direct 95 2 2 8 12 1.5
SUBB A, #data 94 2 2 8 12 1.5
XCH A, R0 C8 1 1 4 12 3
XCH A, R1 C9 1 1 4 12 3
XCH A, R2 CA 1 1 4 12 3
XCH A, R3 CB 1 1 4 12 3
XCH A, R4 CC 1 1 4 12 3
XCH A, R5 CD 1 1 4 12 3
XCH A, R6 CE 1 1 4 12 3
XCH A, R7 CF 1 1 4 12 3
XCH A, @R0 C6 1 1 4 12 3
XCH A, @R1 C7 1 1 4 12 3
XCHD A, @R0 D6 1 1 4 12 3
XCHD A, @R1 D7 1 1 4 12 3
XCH A, direct C5 2 2 8 12 1.5
XRL A, R0 68 1 1 4 12 3
XRL A, R1 69 1 1 4 12 3
XRL A, R2 6A 1 1 4 12 3
XRL A, R3 6B 1 1 4 12 3
XRL A, R4 6C 1 1 4 12 3
XRL A, R5 6D 1 1 4 12 3
XRL A, R6 6E 1 1 4 12 3
XRL A, R7 6F 1 1 4 12 3
XRL A, @R0 66 1 1 4 12 3
XRL A, @R1 67 1 1 4 12 3
XRL A, direct 65 2 2 8 12 1.5
XRL A, #data 64 2 2 8 12 1.5
XRL direct, A 62 2 2 8 12 1.5
XRL direct, #data 63 3 3 12 24 2
9.1 Instruction Timing
n UVOTO n =
Preliminary N79E352/N79E352R Data Sheet
Publication Release Date: Jul, 29, 2009
- 59 - Revision A06
The instruction timing for the N79E352(R) is an important aspect, especially for those users who wish
to use software instructions to generate timing delays. Also, it provides the user with an insight into the
timing differences between the N79E352(R) and the standard 8052. In the N79E352(R) each machine
cycle is four clock periods long. Each clock period is designated a state. Thus each machine cycle is
made up of four states, C1, C2 C3 and C4, in that order. Due to the reduced time for each instruction
execution, both the clock edges are used for internal timing. Hence it is important that the duty cycle of
the clock be as close to 50% as possible to avoid timing conflicts. As mentioned earlier, the
N79E352(R) does one op-code fetch per machine cycle. Therefore, in most of the instructions, the
number of machine cycles needed to execute the instruction is equal to the number of bytes in the
instruction. Of the 256 available op-codes, 128 of them are single cycle instructions. Thus more than
half of all op-codes in the N79E352(R) are executed in just four clock periods. Most of the two-cycle
instructions are those that have two byte instruction codes. However there are some instructions that
have only one byte instructions, yet they are two cycle instructions. One instruction which is of
importance is the MOVX instruction. In the standard 8052, the MOVX instruction is always two machine
cycles long. However in the N79E352(R), the user has a facility to stretch the duration of this instruction
from 2 machine cycles to 9 machine cycles. The
RD
and
WR
strobe lines are also proportionately
elongated. This gives the user flexibility in accessing both fast and slow peripherals without the use of
external circuitry and with minimum software overhead. The rest of the instructions are either three,
four or five machine cycle instructions. Note that in the N79E352(R), based on the number of machine
cycles, there are five different types, while in the standard 8052 there are only three. However, in the
N79E352(R) each machine cycle is made of only 4 clock periods compared to the 12 clock periods for
the standard 8052. Therefore, even though the number of categories has increased, each instruction is
at least 1.5 to 3 times faster than the standard 8052 in terms of clock periods.
Single Cycle
C4
C3C2
C1
CLK
ALE
PSEN
AD7-0
PORT 2
A7-0
Address A15-8
Data_ in D7-0
Figure 9-1: Single Cycle Instruction Timing
n UVOTO n
Preliminary N79E352/N79E352R Data Sheet
- 60 -
Instruction Fetch
C4
C3
C2
C1
OP-CODE
Address A15-8
Address A15-8
ALE
PSEN
PC
AD7-0
PORT 2
CLK
Operand Fetch
C4
C3
C2
C1
OPERAND
PC+1
Figure 9-2: Two Cycle Instruction Timing
OPERAND
OPERAND A7-0
A7-0 A7-0OP-CODE
Address A15-8
Address A15-8Address A15-8
Operand Fetch
Operand FetchInstruction Fetch
C2 C3 C4
C2 C3 C4C4
C3C2 C1
C1C1
CLK
ALE
PSEN
AD7-0
PORT 2
Figure 9-3: Three Cycle Instruction Timing
n UVOTO n NOAH X0 HAX ND) >—
Preliminary N79E352/N79E352R Data Sheet
Publication Release Date: Jul, 29, 2009
- 61 - Revision A06
OPERAND
OPERAND
OPERAND
OP-CODE
Address A15-8
Address A15-8
Address A15-8
Address A15-8
A7-0
A7-0
A7-0
A7-0
Operand Fetch
Operand Fetch
Operand Fetch
Instruction Fetch
C2
C1 C4
C3
C2
C1
CLK
ALE
PSEN
AD7-0
Port 2
C4
C3 C2
C1 C4
C3 C2
C1 C4
C3
Figure 9-4: Four Cycle Instruction Timing
OPERAND
OPERAND
OPERAND
OP-CODE
Address A15-8
Address A15-8
Address A15-8
Address A15-8
A7-0
A7-0
A7-0
A7-0
Operand Fetch Operand Fetch
Operand Fetch
Operand Fetch
Instruction Fetch
C2
C1 C4
C3
C2
C1
CLK
ALE
PSEN
AD7-0
PORT 2
C4
C3 C2
C1 C4
C3 C2
C1 C4
C3 C2
C1 C4
C3
OPERAND
A7-0
Address A15-8
Figure 9-5: Five Cycle Instruction Timing
n UVOTO n
Preliminary N79E352/N79E352R Data Sheet
- 62 -
9.2 MOVX Instruction
The N79E352(R), like the standard 8052, uses the MOVX instruction to access external Data Memory.
This Data Memory includes both off-chip memory as well as memory mapped peripherals. While the
results of the MOVX instruction are the same as in the standard 8052, the operation and the timing of
the strobe signals have been modified in order to give the user much greater flexibility.
The MOVX instruction is of two types, the MOVX @Ri and MOVX @DPTR. In the MOVX @Ri, the
address of the external data comes from two sources. The lower 8-bits of the address are stored in the
Ri register of the selected working register bank. The upper 8-bits of the address come from the port 2
SFR. In the MOVX @DPTR type, the full 16-bit address is supplied by the Data Pointer.
Since the N79E352(R) has two Data Pointers, DPTR and DPTR1, the user has to select between the
two by setting or clearing the DPS bit. The Data Pointer Select bit (DPS) is the LSB of the DPS SFR,
which exists at location 86h. No other bits in this SFR have any effect, and they are set to 0. When
DPS is 0, then DPTR is selected, and when set to 1, DPTR1 is selected. The user can switch between
DPTR and DPTR1 by toggling the DPS bit. The quickest way to do this is by the INC instruction. The
advantage of having two Data Pointers is most obvious while performing block move operations. The
accompanying code shows how the use of two separate Data Pointers speeds up the execution time
for code performing the same task.
Block Move with single Data Pointer:
; SH and SL are the high and low bytes of Source Address
; DH and DL are the high and low bytes of Destination Address
; CNT is the number of bytes to be moved
Machine Cycles of
N79E352(R)
#
MOV R2, #CNT ; Load R2 with the count value 2
MOV R3, #SL ; Save low byte of Source Address in R3 2
MOV R4, #SH ; Save high byte of Source address in R4 2
MOV R5, #DL ; Save low byte of Destination Address in R5 2
MOV R6, #DH ; Save high byte of Destination address in R6 2
LOOP:
MOV DPL, R3 ; Load DPL with low byte of Source address 2
MOV DPH, R4 ; Load DPH with high byte of Source address 2
MOVX A, @DPTR ; Get byte from Source to Accumulator 2
INC DPTR ; Increment Source Address to next byte 2
MOV R3, DPL ; Save low byte of Source address in R3 2
MOV R4, DPH ; Save high byte of Source Address in R4 2
MOV DPL, R5 ; Load low byte of Destination Address in DPL 2
MOV DPH, R6 ; Load high byte of Destination Address in DPH 2
MOVX @DPTR, A ; Write data to destination 2
INC DPTR ; Increment Destination Address 2
MOV DPL, R5 ; Save low byte of new destination address in R5 2
MOV DPH, R6 ; Save high byte of new destination address in R6 2
DJNZ R2, LOOP ; Decrement count and do LOOP again if count <> 0 2
n UVOTO n
Preliminary N79E352/N79E352R Data Sheet
Publication Release Date: Jul, 29, 2009
- 63 - Revision A06
Machine cycles in standard 8052 = 10 + (26 * CNT)
Machine cycles in N79E352(R) = 10 + (26 * CNT)
If CNT = 50
Clock cycles in standard 8052= ((10 + (26 *50)) * 12 = (10 + 1300) * 12 = 15720
Clock cycles in N79E352(R) = ((10 + (26 * 50)) * 4 = (10 + 1300) * 4 = 5240
Block Move with Two Data Pointers in N79E352(R):
; SH and SL are the high and low bytes of Source Address
; DH and DL are the high and low bytes of Destination Address
; CNT is the number of bytes to be moved
Machine Cycles of N79E352(R)
#
MOV R2, #CNT ; Load R2 with the count value 2
MOV DPS, #00h ; Clear DPS to point to DPTR 2
MOV DPTR, #DHDL ; Load DPTR with Destination address 3
INC DPS ; Set DPS to point to DPTR1 2
MOV DPTR, #SHSL ; Load DPTR1 with Source address 3
LOOP:
MOVX A, @DPTR ; Get data from Source block 2
INC DPTR ; Increment source address 2
DEC DPS ; Clear DPS to point to DPTR 2
MOVX @DPTR, A ; Write data to Destination 2
INC DPTR ; Increment destination address 2
INC DPS ; Set DPS to point to DPTR1 2
DJNZ R2, LOOP ; Check if all done 3
Machine cycles in N79E352(R) = 12 + (15 * CNT)
If CNT = 50
Clock cycles in N79E352(R) = (12 + (15 * 50)) * 4 = (12 + 750) * 4 = 3048
We can see that in the first program the standard 8052 takes 15720 cycles, while the N79E352(R)
takes only 5240 cycles for the same code. In the second program, written for the N79E352(R),
program execution requires only 3048 clock cycles. If the size of the block is increased then the saving
is even greater.
9.3 External Data Memory Access Timing
The timing for the MOVX instruction is another feature of the N79E352(R). In the standard 8052, the
MOVX instruction has a fixed execution time of 2 machine cycles. However in the N79E352(R), the
duration of the access can be varied by the user.
The instruction starts off as a normal op-code fetch of 4 clocks. In the next machine cycle, the
N79E352(R) puts out the address of the external Data Memory and the actual access occurs here. The
user can change the duration of this access time by setting the STRETCH value. The Clock Control
SFR (CKCON) has three bits that control the stretch value. These three bits are M2-0 (bits 2-0 of
CKCON). These three bits give the user 8 different access time options. The stretch can be varied
from 0 to 7, resulting in MOVX instructions that last from 2 to 9 machine cycles in length. Note that the
stretching of the instruction only results in the elongation of the MOVX instruction, as if the state of the
CPU was held for the desired period. There is no effect on any other instruction or its timing. By
n UVOTO n
Preliminary N79E352/N79E352R Data Sheet
- 64 -
default, the Stretch value is set at 1, giving a MOVX instruction of 3 machine cycles. If desired by the
user the stretch value can be set to 0 to give the fastest MOVX instruction of only 2 machine cycles.
Table 9-3: Data Memory Cycle Stretch Values
M2 M1 M0 Machine
Cycles
RD
or
WR
strobe width
in Clocks
RD
or
WR
strobe width
@ 20 MHz
0 0 0 2 2 100 nS
0 0 1 3 (default) 4 200 nS
0 1 0 4 8 400 nS
0 1 1 5 12 600 nS
1 0 0 6 16 800 nS
1 0 1 7 20 1000 nS
1 1 0 8 24 1200 nS
1 1 1 9 28 1400 nS
Next Instruction
Machine Cycle
Second
Machine cycle
First
Machine cycle
Last Cycle
of Previous
Instruction
C4
PORT 2
PORT 0
WR
PSEN
ALE
CLK
C3C2
D0-D7A0-A7
D0-D7
A0-A7
D0-D7
A0-A7
D0-D7
A15-A8
A15-A8A15-A8A15-A8
A0-A7
C1 C4C3C2C1 C4C3C2C1 C4C3C2C1
MOVX instruction cycle
Next Inst. Read
Next Inst.
Address
MOVX Data out
MOVX Data
Address
MOVX Inst.
Address
MOVX Inst
.
Figure 9-6: Data Memory Write with Stretch Value = 0
n UVOTO n = \ Lil I; | \||\||c||||\||\||\|||| W W m m m —\ |_||_| |_ ——|_l— 3%??? If HZI—ll 347 X47 XJ;
Preliminary N79E352/N79E352R Data Sheet
Publication Release Date: Jul, 29, 2009
- 65 - Revision A06
Next Instruction
Machine Cycle
Third
Machine Cycle
Second
Machine Cycle
First
Machine Cycle
Last Cycle
of Previous
Instruction
C4
PORT 2
PORT 0
WR
PSEN
ALE
CLK
C3
C2
D0-D7
A0-A7
D0-D7
A0-A7
D0-D7
A0-A7
D0-D7
A15-A8A15-A8
A15-A8A15-A8
A0-A7
C1 C4C3
C2
C1 C4C3C2C1 C4C3C2C1
MOVX instruction cycle
Next Inst.
Read
Next Inst.
Address MOVX Data out
MOVX Data
Address
MOVX Inst.
Address
MOVX Inst.
C4C3C2C1
Figure 9-7: Data Memory Write with Stretch Value = 1
n UVOTO n = rs— 4% \ll\IHIIIIHHIIIIHIHI W m l_| l_| l_| —\|_l\_l g ——|—I— j—Q—(Tfifl 1r l-I—II J; 4; 4; WAIT
Preliminary N79E352/N79E352R Data Sheet
- 66 -
Next
Instruction
Machine Cycle
Fourth
Machine Cycle
Third
Machine Cycle
Second
Machine Cycle
First
Machine Cycle
Last Cycle
of Previous
Instruction
C4
PORT 2
PORT 0
WR
PSEN
ALE
CLK
C3C2
D0-D7
A0-A7
D0-D7
A0-A7
D0-D7
A0-A7
D0-D7
A15-A8
A15-A8A15-A8
A15-A8
A0-A7
C1 C4C3C2C1 C4C3C2C1 C4C3C2C1
MOVX instruction cycle
Next Inst.
Read
Next Inst.
Address MOVX Data out
MOVX Data
Address
MOVX Inst.
Address
MOVX Inst.
C4C3C2C1 C4
C3
C2C1
Figure 9-8: Data Memory Write with Stretch Value = 2
9.4 Wait State Control Signal
Either with the software using stretch value to change the required machine cycle of MOVX instruction,
the N79E352(R) provides another hardware signal
WAIT
to implement the wider duration of external
data access timing. This wait state control signal is the alternate function of P4.0. The wait state control
signal can be enabled by setting WS (SFR ROMMAP.7) bit. When enabled, the setting of stretch value
decides the minimum length of MOVX instruction cycle and the device will sample the
WAIT
pin at
each C2 state before the rising edge of read/write strobe signal during MOVX instruction. Once this
signal being recongnized, one more machine cycle (wait state cycle) will be inserted into next cycle.
The inserted wait state cycles are unlimited, so the MOVX instruction cycle will end in which the wait
state control signal is deactivated. Using wait state control signal allows a dynamically access timimg to
a selected external peripheral. The WS bit is accessed by the Timed Access Protection procedure.
n UVOTO n E CD1 CDO Clocks/Machine Cycle
Preliminary N79E352/N79E352R Data Sheet
Publication Release Date: Jul, 29, 2009
- 67 - Revision A06
10. POWER MANAGEMENT
The N79E352(R) has several features that help the user to control the power consumption of the
device. The power saving features are basically the POWER DOWN mode, ECONOMY mode and
the IDLE mode of operation.
10.1 Idle Mode
The user can put the device into idle mode by writing 1 to the bit PCON.0. The instruction that sets the
idle bit is the last instruction that will be executed before the device goes into Idle Mode. In the Idle
mode, the clock to the CPU is halted, but not to the Interrupt, Timer, Watchdog timer and Serial port
blocks. This forces the CPU state to be frozen; the Program counter, the Stack Pointer, the Program
Status Word, the Accumulator and the other registers hold their contents. The port pins hold the logical
states they had at the time Idle was activated. The Idle mode can be terminated in two ways. Since the
interrupt controller is still active, the activation of any enabled interrupt can wake up the processor. This
will automatically clear the Idle bit, terminate the Idle mode, and the Interrupt Service Routine(ISR) will
be executed. After the ISR, execution of the program will continue from the instruction which put the
device into Idle mode.
The Idle mode can also be exited by activating the reset. The device can be put into reset either by
applying a high on the external RST pin, a Power on reset condition or a Watchdog timer reset. The
external reset pin has to be held high for at least two machine cycles i.e. 8 clock periods to be
recognized as a valid reset. In the reset condition the program counter is reset to 0000h and all the
SFRs are set to the reset condition. Since the clock is already running there is no delay and execution
starts immediately. In the Idle mode, the Watchdog timer continues to run, and if enabled, a time-out
will cause a watchdog timer interrupt which will wake up the device. The software must reset the
Watchdog timer in order to preempt the reset which will occur after 512 clock periods of the time-out.
When the N79E352(R) is exiting from an Idle mode with a reset, the instruction following the one which
put the device into Idle mode is not executed. So there is no danger of unexpected writes.
10.2 Economy Mode
The power consumption of microcontroller relates to operating frequency. The N79E352(R) offers a
Economy mode to reduce the internal clock rate dynamically without external components. By default,
one machine cycle needs 4 clocks. In Economy mode, software can select 4, 64 or 1024 clocks per
machine cycle. It keeps the CPU operating at a acceptable speed but eliminates the power
consumption. In the Idle mode, the clock of the core logic is stopped, but all clocked peripherals such
as watchdog timer are still running at a rate of clock/4. In the Economy mode, all clocked peripherals
run at the same reduced clocks rate as in core logic. So the Economy mode may provide a lower
power consumption than idle mode.
Software invokes the Economy mode by setting the appropriate bits in the SFRs. Setting the bits
CD0(PMR.6), CD1(PMR.7) decides the instruction cycle rate as below:
CD1 CD0 Clocks/Machine Cycle
0 X 4 (default)
1 0 64
1 1 1024
The selection of instruction rate is going to take effect after a delay of one instruction cycle. Switching
to divide by 64 or 1024 mode must first go from divide by 4 mode. This means software can not switch
directly between clock/64 and clock/1024 mode. The CPU has to return clock/4 mode first, then go to
clock/64 or clock/1024 mode.
In Economy mode, the serial port can not receive/transmit data correctly because the baud rate is
changed. In some systems, the external interrupts may require the fastest process such that the
n UVOTO n
Preliminary N79E352/N79E352R Data Sheet
- 68 -
reducing of operating speed is restricted. In order to solve these dilemmas, the N79E352(R) offers a
switchback feature which allows the CPU back to clock/4 mode immediately when triggered by serial
operation (uart and I2C) or external interrupts. The switchback feature is enabled by setting the SWB
bit (PMR.5). A serial port/I2C reception/transmission or qualified external interrupt which is enabled
and acknowledged without block conditions will cause CPU to return to divide by 4 mode. For the serial
port reception, a switchback is generated by a falling edge associated with start bit if the serial port
reception is enabled. When a serial port transmission, an instruction which writes a byte of data to
serial port buffer will cause a switchback to ensure the correct transmission. The switchback feature is
unaffected by serial port interrupt flags. Similarly for I2C reception/transmission, a switchback is
generated when a start condition is determined. After a switchback is generated, the software can
manually return the CPU to Economy mode. Note that the modification of clock control bits CD0 and
CD1 will be ignored during I2C or serial port transmit/receive when switchback is enabled. The
Watchdog timer reset, power-on/fail reset, software reset, brownout reset or external reset will force
the CPU to return to divide by 4 mode.
10.3 Power Down Mode
The device can be put into Power Down mode by writing 1 to bit PCON.1. The instruction that does this
will be the last instruction to be executed before the device goes into Power Down mode. In the Power
Down mode, all the clocks are stopped and the device comes to a halt. All activity is completely
stopped and the power consumption is reduced to the lowest possible value. In this state the ALE and
PSEN
pins are pulled low. The port pins output the values held by their respective SFRs.
The N79E352(R) will exit the Power Down mode with a reset or by an external interrupt pin. An
external reset can be used to exit the Power down state. The high on RST pin terminates the Power
Down mode, and restarts the clock. The program execution will restart from 0000h. In the Power down
mode, the clock is stopped, so the Watchdog timer cannot be used to provide the reset to exit Power
down mode when its clock source is external OSC or crystal.
The sources that can wake up from the power down mode are external interrupts, keyboard interrupt
(KBI), brownout reset (BOR), and watchdog timer interrupt (if WDTCK = 0).
The N79E352(R) can be woken from the Power Down mode by forcing an external interrupt pin
activated, provided the corresponding interrupt is enabled, while the global enable(EA) bit is set and
the external input has been set to a level detect mode. If these conditions are met, then the low level
on the external pin re-starts the oscillator. Then device executes the interrupt service routine for the
corresponding external interrupt. After the interrupt service routine is completed, the program execution
returns to the instruction after the one which put the device into Power Down mode and continues from
there.
n UVOTO n
Preliminary N79E352/N79E352R Data Sheet
Publication Release Date: Jul, 29, 2009
- 69 - Revision A06
11. RESET CONDITIONS
The user has several hardware related options for placing the N79E352(R) into reset condition. In
general, most register bits go to their reset value irrespective of the reset condition, but there are a few
flags whose state depends on the source of reset. The user can use these flags to determine the
cause of reset using software.
11.1 Sources of reset
11.1.1 External Reset
The device samples the RST pin every machine cycle during state C4. The RST pin must be held high
for at least two machine cycles before the reset circuitry applies an internal reset signal. Thus, this
reset is a synchronous operation and requires the clock to be running.
The device remains in the reset state as long as RST pin is high and remains high up to two machine
cycles after RST is deactivated. Then, the device begins program execution at 0000h. There are no
flags associated with the external reset, but, since the other two reset sources do have flags, the
external reset is the cause if those flags are clear.
11.1.2 Power-On Reset (POR)
When the power supply rises to the configured level, VRST, the device will perform a power on reset and
set the POR flag. The software should clear the POR flag, or it will be difficult to determine the source
of future resets.
11.1.3 Brown-Out Reset (BOR)
If the power supply falls below brownout voltage of VBOV, the device goes into the reset state. When the
power supply returns to proper levels, the device performs a brownout reset.
11.1.4 Watchdog Timer Reset
The Watchdog Timer is a free-running timer with programmable time-out intervals. The program must
clear the Watchdog Timer before the time-out interval is reached to restart the count. If the time-out
interval is reached, an interrupt flag is set. 512 clocks later, if the Watchdog Reset is enabled and the
Watchdog Timer has not been cleared, the Watchdog Timer generates a reset. The reset condition is
maintained by the hardware for two machine cycles, and the WTRF bit in WDCON is set. Afterwards,
the device begins program execution at 0000h.
11.1.5 Software Reset
N79E352(R) is enhanced by a software reset. This allows the program code to reset the whole system
in software approach. Just writer 1 to SRET bit in AUXR1.3, a software reset will perform. Note that
SRST require Timed Access procedure to write. Please refer TA register description
11.2 Reset State
When the device is reset, most registers return to their initial state. The Watchdog Timer is disabled if
the reset source was a power-on reset. The Program Counter is set to 0000h, and the stack pointer is
reset to 07h. After this, the device remains in the reset state as long as the reset conditions are
satisfied.
n UVOTO n
Preliminary N79E352/N79E352R Data Sheet
- 70 -
Reset does not affect the on-chip RAM, however, so RAM is preserved as long as VDD remains above
approximately 2V, the minimum operating voltage for the RAM. If VDD falls below 2V, the RAM
contents are also lost. In either case, the stack pointer is always reset, so the stack contents are lost.
The WDCON SFR bits are set/cleared in reset condition depending on the source of the reset.
External reset Watchdog reset Power on reset
WDCON 0xxx0x00b 0xxx0100b 01xx0000b
The POR bit WDCON.6 is set only by the power on reset. WTRF bit WDCON.2 is set when the
Watchdog timer causes a reset. A power on reset will also clear this bit. The EWRST bit WDCON.1 is
cleared by all reset. This disables the Watchdog timer resets.
All the bits in this SFR have unrestricted read access. WDRUN, POR, EWRST, WDIF and WDCLR
require Timed Access procedure to write. The remaining bits have unrestricted write accesses.
n UVOTO n
Preliminary N79E352/N79E352R Data Sheet
Publication Release Date: Jul, 29, 2009
- 71 - Revision A06
12. PROGRAMMABLE TIMERS/COUNTERS
The N79E352(R) has three 16-bit programmable timer/counters and one programmable Watchdog
timer. The Watchdog timer is operationally quite different from the other two timers.
12.1 Timer/Counters 0 & 1
Each of these Timer/Counters has two 8 bit registers which form the 16 bit counting register. For
Timer/Counter 0 they are TH0, the upper 8 bits register, and TL0, the lower 8 bit register. Similarly
Timer/Counter 1 has two 8 bit registers, TH1 and TL1. The two can be configured to operate either as
timers, counting machine cycles or as counters counting external inputs.
When configured as a "Timer", the timer counts clock cycles. The timer clock can be programmed to
be thought of as 1/12 of the system clock or 1/4 of the system clock. In the "Counter" mode, the
register is incremented on the falling edge of the external input pin, T0 in case of Timer 0, and T1 for
Timer 1. The T0 and T1 inputs are sampled in every machine cycle at C4. If the sampled value is high
in one machine cycle and low in the next, then a valid high to low transition on the pin is recognized
and the count register is incremented. Since it takes two machine cycles to recognize a negative
transition on the pin, the maximum rate at which counting will take place is 1/24 of the master clock
frequency. In either the "Timer" or "Counter" mode, the count register will be updated at C3. Therefore,
in the "Timer" mode, the recognized negative transition on pin T0 and T1 can cause the count register
value to be updated only in the machine cycle following the one in which the negative edge was
detected.
The "Timer" or "Counter" function is selected by the " C T/ " bit in the TMOD Special Function Register.
Each Timer/Counter has one selection bit for its own; bit 2 of TMOD selects the function for
Timer/Counter 0 and bit 6 of TMOD selects the function for Timer/Counter 1. In addition each
Timer/Counter can be set to operate in any one of four possible modes. The mode selection is done by
bits M0 and M1 in the TMOD SFR.
12.2 Time-base Selection
The N79E352(R) gives the user two modes of operation for the timer. The timers can be programmed
to operate like the standard 8051 family, counting at the rate of 1/12 of the clock speed. This will
ensure that timing loops on the N79E352(R) and the standard 8051 can be matched. This is the default
mode of operation of the N79E352(R) timers. The user also has the option to count in the turbo mode,
where the timers will increment at the rate of 1/4 clock speed. This will straight-away increase the
counting speed three times. This selection is done by the T0M and T1M bits in CKCON SFR. A reset
sets these bits to 0, and the timers then operate in the standard 8051 mode. The user should set these
bits to 1 if the timers are to operate in turbo mode.
12.2.1 Mode 0
In Mode 0, the timer/counters act as a 8 bit counter with a 5 bit, divide by 32 pre-scale. In this mode we
have a 13 bit timer/counter. The 13 bit counter consists of 8 bits of THx and 5 lower bits of TLx. The
upper 3 bits of TLx are ignored.
The negative edge of the clock increments the count in the TLx register. When the fifth bit in TLx
moves from 1 to 0, then the count in the THx register is incremented. When the count in THx moves
from FFh to 00h, then the overflow flag TFx in TCON SFR is set. The counted input is enabled only if
TRx is set and either GATE = 0 or
INTx
= 1. When
C T/
is set to 0, then it will count clock cycles, and
if
C T/
is set to 1, then it will count 1 to 0 transitions on T0 (P3.4) for timer 0 and T1 (P3.5) for timer 1.
When the 13 bit count reaches 1FFFh the next count will cause it to roll-over to 0000h. The timer
overflow flag TFx of the relevant timer is set and if enabled an interrupts will occur. Note that when
used as a timer, the time-base may be either clock cycles/12 or clock cycles/4 as selected by the bits
TxM of the CKCON SFR.
n UVOTO n
Preliminary N79E352/N79E352R Data Sheet
- 72 -
1/4
1/12
C/T = TMOD.2
(C/T = TMOD.6)
T0M = CKCON.3
(T1M = CKCON.4) M1,M0 = TMOD.1,TMOD.0
(M1,M0 = TMOD.5,TMOD.4)
Interrupt
T0 = P3.4
(T1 = P3.5) TH0
(TH1)
TL0
(TL1)
TF0
(TF1)
TR0 = TCON.4
(TR1 = TCON.6)
GATE = TMOD.3
(GATE = TMOD.7)
INT0 = P3.2
(INT1 = P3.3)
70
TFx
4 70
Timer 1 functions are shown in brackets
1
00
0
0
1
01
Fcpu
Figure 12-1: Timer/Counter Mode 0 & Mode 1
n UVOTO n =
Preliminary N79E352/N79E352R Data Sheet
Publication Release Date: Jul, 29, 2009
- 73 - Revision A06
12.2.2 Mode 1
Mode 1 is similar to Mode 0 except that the counting register forms a 16 bit counter, rather than a 13
bit counter. This means that all the bits of THx and TLx are used. Roll-over occurs when the timer
moves from a count of FFFFh to 0000h. The timer overflow flag TFx of the relevant timer is set and if
enabled an interrupt will occur. The selection of the time-base in the timer mode is similar to that in
Mode 0. The gate function operates similarly to that in Mode 0.
12.2.3 Mode 2
In Mode 2, the timer/counter is in the Auto Reload Mode. In this mode, TLx acts as a 8 bit count
register, while THx holds the reload value. When the TLx register overflows from FFh to 00h, the TFx
bit in TCON is set and TLx is reloaded with the contents of THx, and the counting process continues
from here. The reload operation leaves the contents of the THx register unchanged. Counting is
enabled by the TRx bit and proper setting of GATE and
INTx
pins. As in the other two modes 0 and 1
mode 2 allows counting of either clock cycles (clock/12 or clock/4) or pulses on pin Tn.
1/4
1/12
C/T = TMOD.2
(C/T = TMOD.6)
T0M = CKCON.3
(T1M = CKCON.4)
Interrupt
T0 = P3.4
(T1 = P3.5)
TH0
(TH1)
TL0
(TL1)
TF0
(TF1)
TR0 = TCON.4
(TR1 = TCON.6)
GATE = TMOD.3
(GATE = TMOD.7)
INT0 = P3.2
(INT1 = P3.3)
7
0TFx
4
70
Timer 1 functions are shown in brackets
1
0
0
1
Fcpu
Figure 12-2: Timer/Counter Mode 2
12.2.4 Mode 3
Mode 3 has different operating methods for the two timer/counters. For timer/counter 1, mode 3 simply
freezes the counter. Timer/Counter 0, however, configures TL0 and TH0 as two separate 8 bit count
registers in this mode. The logic for this mode is shown in the figure. TL0 uses the Timer/Counter 0
control bits
C T/
, GATE, TR0,
INT0
and TF0. The TL0 can be used to count clock cycles (clock/12 or
clock/4) or 1-to-0 transitions on pin T0 as determined by C/T (TMOD.2). TH0 is forced as a clock cycle
counter (clock/12 or clock/4) and takes over the use of TR1 and TF1 from Timer/Counter 1. Mode 3 is
used in cases where an extra 8 bit timer is needed. With Timer 0 in Mode 3, Timer 1 can still be used
in Modes 0, 1 and 2., but its flexibility is somewhat limited. While its basic functionality is maintained, it
no longer has control over its overflow flag TF1 and the enable bit TR1. Timer 1 can still be used as a
timer/counter and retains the use of GATE and INT1 pin. In this condition it can be turned on and off by
switching it out of and into its own Mode 3. It can also be used as a baud rate generator for the serial
port.
n UVOTO n if] §
Preliminary N79E352/N79E352R Data Sheet
- 74 -
1/4
1/12
C/T = TMOD.2
T0M = CKCON.3
Interrupt
T0 = P3.4
TH0
TL0
TR0 = TCON.4
GATE = TMOD.3
INT0 = P3.2
7
0TF0
4
7
0
1
0
0
1
Fcpu
TR1 = TCON.6 Interrupt
TF1
Figure 12-3: Timer/Counter 0 Mode 3
12.3 Timer/Counter 2
Timer/Counter 2 is a 16 bit up/down counter which is configured by the T2MOD register and controlled
by the T2CON register. Timer/Counter 2 is equipped with a capture/reload capability. As with the Timer
0 and Timer 1 counters, there exists considerable flexibility in selecting and controlling the clock, and in
defining the operating mode. The clock source for Timer/Counter 2 may be selected for either the
external T2 pin (C/T2 = 1) or the crystal oscillator, which is divided by 12 or 4 (C/T2 = 0). The clock is
then enabled when TR2 is a 1, and disabled when TR2 is a 0.
12.3.1 Capture Mode
The capture mode is enabled by setting the
CP RL/ 2
bit in the T2CON register to a 1. In the capture
mode, Timer/Counter 2 serves as a 16 bit up counter. When the counter rolls over from FFFFh to
0000h, the TF2 bit is set, which will generate an interrupt request. If the EXEN2 bit is set, then a
negative transition of T2EX pin will cause the value in the TL2 and TH2 register to be captured by the
RCAP2L and RCAP2H registers. This action also causes the EXF2 bit in T2CON to be set, which will
also generate an interrupt. Setting the T2CR bit (T2MOD.3), the N79E352(R) allows hardware to reset
timer 2 automatically after the value of TL2 and TH2 have been captured.
n UVOTO n [i i, \/
Preliminary N79E352/N79E352R Data Sheet
Publication Release Date: Jul, 29, 2009
- 75 - Revision A06
1/4
1/12
Fcpu
T2=P1.0
0
1
0
1
T2EX=P1.1
T2M=CKCON.5
C/T2=T2CON.1
EXF2
Timer2
Interrupt
T2CON.6
TR2=T2CON.2
EXEN2=T2CON.3
TL2 TH2
RCAP2L RCAP2H
TF2
T2CON.7
Figure 12-4: Timer 2 16-Bit Capture Mode
12.3.2 Auto-Reload Mode, Counting up
The auto-reload mode as an up counter is enabled by clearing the
CP RL/ 2
bit in the T2CON register
and clearing the DCEN bit in T2MOD register. In this mode, Timer/Counter 2 is a 16 bit up counter.
When the counter rolls over from FFFFh, a reload is generated that causes the contents of the
RCAP2L and RCAP2H registers to be reloaded into the TL2 and TH2 registers. The reload action also
sets the TF2 bit. If the EXEN2 bit is set, then a negative transition of T2EX pin will also cause a reload.
This action also sets the EXF2 bit in T2CON.
1/4
1/12
Fcpu
T2=P1.0
0
1
0
1
T2EX=P1.1
T2M=CKCON.5
C/T2=T2CON.1
EXF2
Timer2
Interrupt
T2CON.6
TR2=T2CON.2
EXEN2=T2CON.3
TL2 TH2
RCAP2L RCAP2H
TF2
T2CON.7
Figure 12-5: Timer 2 16-Bit Auto-reload Mode, Counting Up
12.3.3 Auto-Reload Mode, Counting Up/Down
Timer/Counter 2 will be in auto-reload mode as an up/down counter if
CP RL/ 2
bit in T2CON is
cleared and the DCEN bit in T2MOD is set. In this mode, Timer/Counter 2 is an up/down counter
whose direction is controlled by the T2EX pin. A 1 on this pin cause the counter to count up. An
overflow while counting up will cause the counter to be reloaded with the contents of the capture
n UVOTO n |::| i] J? ii—CE—fi
Preliminary N79E352/N79E352R Data Sheet
- 76 -
registers. The next down count following the case where the contents of Timer/Counter equal the
capture registers will load an FFFFh into Timer/Counter 2. In either event a reload will set the TF2 bit.
A reload will also toggle the EXF2 bit. However, the EXF2 bit can not generate an interrupt while in this
mode.
1/4
1/12
Fcpu
T2=P1.0
0
1
0
1
T2EX=P1.1
T2M=CKCON.5
C/T2=T2CON.1
EXF2
Timer2
Interrupt
T2CON.6
TR2=T2CON.2
TL2 TH2
RCAP2L RCAP2H
TF2
T2CON.7
0FFh 0FFh
Down Counting Reload Value
Up Counting Reload Value
Figure 12-6: Timer 2 16-Bit Auto-reload Up/Down Counter
12.3.4 Baud Rate0 Generator Mode
The baud rate generator mode is enabled by setting either the RCLK or TCLK bits in T2CON register.
While in the baud rate generator mode, Timer/Counter 2 is a 16 bit counter with auto reload when the
count rolls over from FFFFh. However, rolling over does not set the TF2 bit. If EXEN2 bit is set, then a
negative transition of the T2EX pin will set EXF2 bit in the T2CON register and cause an interrupt
request.
Fcpu
T2=P1.0
0
1
T2EX=P1.1
C/T2=T2CON.1
EXF2Timer2
Interrupt
T2CON.6
TR2=T2CON.2
EXEN2=T2CON.3
TL2TH2
RCAP2L RCAP2H
Timer2
Overflow
1/2
Figure 12-7: Baud Rate Generator Mode
n UVOTO n — —
Preliminary N79E352/N79E352R Data Sheet
Publication Release Date: Jul, 29, 2009
- 77 - Revision A06
12.3.5 Programmable Clock-out
Timer 2 is equipped with a new clock-out feature which outputs a 50% duty cycle clock on P1.0. It can
be invoked as a programmable clock generator. To configure Timer 2 with clock-out mode, software
must initiate it by setting bit T2OE = 1, C/T2 = 0 and CP/RL = 0. Setting bit TR2 will start the timer. This
mode is similar to the baud rate generator mode, it will not generate an interrupt while Timer 2
overflow. So it is possible to use Timer 2 as a baud rate generator and a clock generator at the same
time. The clock-out frequency is determined by the following equation:
The Clock-Out Frequency = Oscillator Frequency / [4 X 65536-(RCAP2H, RCAP2L) ]
Fcpu
T2EX=P1.1
EXF2Timer2
Interrupt
T2CON.6
TR2=T2CON.2
EXEN2=T2CON.3
TL2TH2
RCAP2L RCAP2H
Timer2
Overflow
1/2 T2=P1.0
1/2
Figure 12-8: Programmable Clock-Out Mode
n UVOTO n E
Preliminary N79E352/N79E352R Data Sheet
- 78 -
13. NVM MEMORY
The N79E352(R) has NVM data memory of 128 bytes for customer’s data store used. The NVM data
memory has 8 pages area and each page has 16 bytes.
13.1 Operation
User is required to enable EnNVM (NVMCON.5) bit for NVM read. This is due to overlapping of NVM
data memory and external data memory physical address, the following table is defined. EnNVM bit
(NVMCON.5) will enable read access to NVM data memory area.
EnNVM
Data Memory Area
0 Enable External RAM read/write access by
MOVX
1
Enable NVM data Memory read access by
MOVX only. If EER or EWR is set and NVM
flash erase or write control is busy, to set this
bit read NVM data is invalid.
Table 13-1: MOVX instruction to Enable Read Data Memory Area Definition Table
The NVM memory can be read/write by customer program to access. Read NVM data is by MOVX
A,@DPTR/R0/R1 instructions, and write data is by SFR of NVMADDR, NVMDAT and NVMCON.
Before write data to NVM memory, the page must be erased by providing page address on
NVMADDR, which address of On-Chip Code Memory space will decode, then set EER of NVMCON.7.
This will automatically hold fetch program code and PC Counter, and execute page erase. After
finished, this bit will be cleared by hardware. The erase time is ~ 5ms.
For writing data to NVM memory, user must set address and data to NVMADDR and NVMDAT, then
set EWR of NVMCON.6 to initiate nvm data write. The uC will hold program code and PC Counter, and
then write data to mapping address. Upon write completion, the EWR bit will be cleared by hardware,
the uC will continue execute next instruction. The program time is ~50us.
NVM data Flash Memory is permanently operating from 11.0592MHz internal clock source. In order to
reduce power consumption, the on chip oscillator will only be enabled when during program or erase,
through EWR or EER in NVMCON SFR. EWR or EER bits are cleared by hardware after program or
erase completed. The program/erase time is automatically controlled by hardware.
n UVOTO n = Imerggl Signal / \
Preliminary N79E352/N79E352R Data Sheet
Publication Release Date: Jul, 29, 2009
- 79 - Revision A06
11.0592MHz
RC OSC
NVM Data
Memory
Block
EnNVM
Clock
Source
EER
EWR
ERC
Internal Signal
Figure 13-1: NVM control
Instructions EnNVM = 0 EnNVM = 1
Addr within
NVM
address
range
Addr out of
NVM address
range
MOVX A, @DPTR
(Read)
Ext memory NVM Ext memory
MOVX A, @R0
(Read)
Ext memory NVM Ext memory[1]
MOVX A, @R1
(Read)
Ext memory NVM Ext memory[1]
MOVX @DPTR, A
(Write)
Ext memory Ext memory Ext memory
MOVX @R0, A
(Write)
Ext memory Ext
memory[1] Ext memory[1]
MOVX @R1, A
(Write)
Ext memory Ext
memory[1] Ext memory[1]
Table 13-2: MOVX read/write access destination
Note: 1. Higher address bytes will come from SFR port 2 values.
For security purposes this NVM data flash provide an independent “Lock bit” located in Security bits, it
is used to protect the customer’s data code in NVM. It may be enabled in CONFIG1.6 after the
programmer finishes the programming and verifies sequence. Once this bit is set to logic 0, NVM Flash
EPROM data can not be accessed again by hardware writer mode.
n UVOTO n
Preliminary N79E352/N79E352R Data Sheet
- 80 -
14. WATCHDOG TIMER
The Watchdog Timer is a free-running Timer which can be programmed by the user to serve as a
system monitor, a time-base generator or an event timer. It is basically a set of dividers that divide the
system clock. The divider output is selectable and determines the time-out interval. When the time-out
occurs a flag is set, which can cause an interrupt if enabled, and a system reset can also be caused if
it is enabled. The interrupt will occur if the individual interrupt enable and the global enable are set. The
interrupt and reset functions are independent of each other and may be used separately or together
depending on the user’s software.
WDIF
512 clock
delay
MUX
20KHz+/-
100% RC
Oscillator
Fcpu
WDTCK
WDRUN
WD1,WD0
WDCLR
EWDI
EWRST
Reset
Interrupt
00
01
10
11
WTRF
15-bits Counter Time-Out
Selector
50
6 8
9 12
13 14
(Reset Watchdog)
(WDCON.1)
(WDCON.3)
(EIE.4) (WDCON.2)
(WDCON.0)
(WDCON.7)
(Security Bit)
(CKCON.7~6)
/Enable
Figure 14-1: Watchdog Timer
The Watchdog Timer should first be restarted by using WDCLR. This ensures that the timer starts
from a known state. The WDCLR bit is used to restart the Watchdog Timer. This bit is self clearing, i.e.
after writing a 1 to this bit the software will automatically clear it. The Watchdog Timer will now count
clock cycles. The time-out interval is selected by the two bits WD1 and WD0 (CKCON.7 and
CKCON.6). When the selected time-out occurs, the Watchdog interrupt flag WDIF (WDCON.3) is set.
After the time-out has occurred, the Watchdog Timer waits for an additional 512 clock cycles. If the
Watchdog Reset EWRST (WDCON.1) is enabled, then 512 clocks after the time-out, if there is no
WDCLR, a system reset due to Watchdog Timer will occur. This will last for two machine cycles, and
the Watchdog Timer reset flag WTRF (WDCON.2) will be set. This indicates to the software that the
Watchdog was the cause of the reset.
When used as a simple timer, the reset and interrupt functions are disabled. The timer will set the
WDIF flag each time the timer completes the selected time interval. The WDIF flag is polled to detect a
time-out and the WDCLR allows software to restart the timer. The Watchdog Timer can also be used
as a very long timer. The interrupt feature is enabled in this case. Every time the time-out occurs an
interrupt will occur if the global interrupt enable EA is set.
The main use of the Watchdog Timer is as a system monitor. This is important in real-time control
applications. In case of some power glitches or electro-magnetic interference, the processor may begin
to execute errant code. If this is left unchecked the entire system may crash. Using the watchdog timer
interrupt during software development will allow the user to select ideal watchdog reset locations. The
code is first written without the watchdog interrupt or reset. Then the Watchdog interrupt is enabled to
identify code locations where interrupt occurs. The user can now insert instructions to reset the
Watchdog Timer, which will allow the code to run without any Watchdog Timer interrupts. Now the
Watchdog Timer reset is enabled and the Watchdog interrupt may be disabled. If any errant code is
n UVOTO n =
Preliminary N79E352/N79E352R Data Sheet
Publication Release Date: Jul, 29, 2009
- 81 - Revision A06
executed now, then the reset Watchdog Timer instructions will not be executed at the required instants
and Watchdog reset will occur.
The Watchdog Timer time-out selection will result in different time-out values depending on the clock
speed. The reset will occur, when enabled, 512 clocks after the time-out has occurred.
WD1 WD0 WATCHDOG
INTERVAL NUMBER OF
CLOCKS TIME
@ 20 KHZ
0
0
26
64
3.2 mS
0
1
29
512
25.6 mS
1
0
213
8192
409.6 mS
1
1
215
32768
1638.4 mS
Table 14-1: Time-out values for the Watchdog timer.
The default Watchdog time-out is 26 clocks, which is the shortest time-out period. The EWRST, WDIF
and WDCLR bits are protected by the Timed Access procedure. This prevents software from
accidentally enabling or disabling the watchdog timer. More importantly, it makes it highly improbable
that errant code can enable or disable the Watchdog Timer.
The security bit WDTCK is located at bit 7 of CONFIG0 register. This bit is for user to configure the
clock source of watchdog timer either from the internal RC or from the uC clock.
n UVOTO n
Preliminary N79E352/N79E352R Data Sheet
- 82 -
15. UART SERIAL PORT
Serial port in the N79E352(R) is a full duplex port. The N79E352(R) provides the user with additional
features such as the Frame Error Detection and the Automatic Address Recognition. The serial ports
are capable of synchronous as well as asynchronous communication. In Synchronous mode the
N79E352(R) generates the clock and operates in a half duplex mode. In the asynchronous mode, full
duplex operation is available. This means that it can simultaneously transmit and receive data. The
transmit register and the receive buffer are both addressed as SBUF Special Function Register.
However any write to SBUF will be to the transmit register, while a read from SBUF will be from the
receive buffer register. The serial port can operate in four different modes as described below.
15.1 Mode 0
This mode provides synchronous communication with external devices. In this mode serial data is
transmitted and received on the RXD line. TXD is used to transmit the shift clock. The TxD clock is
provided by the N79E352(R) whether the device is transmitting or receiving. This mode is therefore a
half duplex mode of serial communication. In this mode, 8 bits are transmitted or received per frame.
The LSB is transmitted/received first. The baud rate is fixed at 1/12 or 1/4 of the oscillator frequency.
This baud rate is determined by the SM2 bit (SCON.5). When this bit is set to 0, then the serial port
runs at 1/12 of the clock. When set to 1, the serial port runs at 1/4 of the clock. This additional facility of
programmable baud rate in mode 0 is the only difference between the standard 8051 and the
N79E352(R).
The functional block diagram is shown below. Data enters and leaves the Serial port on the RxD line.
The TxD line is used to output the shift clock. The shift clock is used to shift data into and out of the
N79E352(R) and the device at the other end of the line. Any instruction that causes a write to SBUF will
start the transmission. The shift clock will be activated and data will be shifted out on the RxD pin till all
8 bits are transmitted. If SM2 = 1, then the data on RxD will appear 1 clock period before the falling
edge of shift clock on TxD. The clock on TxD then remains low for 2 clock periods, and then goes high
again. If SM2 = 0, the data on RxD will appear 3 clock periods before the falling edge of shift clock on
TxD. The clock on TxD then remains low for 6 clock periods, and then goes high again. This ensures
that at the receiving end the data on RxD line can either be clocked on the rising edge of the shift clock
on TxD or latched when the TxD clock is low.
n UVOTO n BLT‘Ii
Preliminary N79E352/N79E352R Data Sheet
Publication Release Date: Jul, 29, 2009
- 83 - Revision A06
1/12
Fcpu
0TX CLOCK
RX CLOCK
TI
RI
TX SHIFT
RX START
RX SHIFT
LOAD SBUF
SHIFT CLOCK
RI
REN
SM2
CLOCK
SIN PAROUT SBUF
Read SBUF
Internal
Data Bus
Serial Controllor
CLOCK
LOAD
PARIN
TX START
Internal
Data BusSBUF
Write to
SOUT
Transmit Shift Register
Serial Interrupt
RXD
TXD
RXD
P3.0 Alternate
Input Function
P3.0 Alternate
Output Function
P3.1 Alternate
Output Function
1/4
1
Figure 15-1: Uart Serial Port Mode 0
The TI flag is set high in C1 following the end of transmission of the last bit. The serial port will receive
data when REN is 1 and RI is zero. The shift clock (TxD) will be activated and the serial port will latch
data on the rising edge of shift clock. The external device should therefore present data on the falling
edge on the shift clock. This process continues till all the 8 bits have been received. The RI flag is set
in C1 following the last rising edge of the shift clock on TxD. This will stop reception, till the RI is
cleared by software.
15.2 Mode 1
In Mode 1, the full duplex asynchronous mode is used. Serial communication frames are made up of
10 bits transmitted on TXD and received on RXD. The 10 bits consist of a start bit (0), 8 data bits (LSB
first), and a stop bit (1). On receive, the stop bit goes into RB8 in the SFR SCON. The baud rate in this
mode is variable. The serial baud can be programmed to be 1/16 or 1/32 of the Timer 1 overflow or
1/16 of Timer 2 overflow. Since the Timer 1 and 2 can be set to different reload values, a wide variation
in baud rates is possible.
Transmission begins with a write to SBUF. The serial data is brought out on to TxD pin at C1 following
the first roll-over of divide by 16 counter. The next bit is placed on TxD pin at C1 following the next
rollover of the divide by 16 counter. Thus the transmission is synchronized to the divide by 16 counter
and not directly to the write to SBUF signal. After all 8 bits of data are transmitted, the stop bit is
transmitted. The TI flag is set in the C1 state after the stop bit has been put out on TxD pin. This will be
at the 10th rollover of the divide by 16 counter after a write to SBUF.
Reception is enabled only if REN is high. The serial port actually starts the receiving of serial data, with
the detection of a falling edge on the RxD pin. The 1-to-0 detector continuously monitors the RxD line,
sampling it at the rate of 16 times the selected baud rate. When a falling edge is detected, the divide by
16 counter is immediately reset. This helps to align the bit boundaries with the rollovers of the divide by
16 counter.
n UVOTO n =
Preliminary N79E352/N79E352R Data Sheet
- 84 -
The 16 states of the counter effectively divide the bit time into 16 slices. The bit detection is done on a
best of three basis. The bit detector samples the RxD pin, at the 8th, 9th and 10th counter states. By
using a majority 2 of 3 voting system, the bit value is selected. This is done to improve the noise
rejection feature of the serial port. If the first bit detected after the falling edge of RxD pin is not 0, then
this indicates an invalid start bit, and the reception is immediately aborted. The serial port again looks
for a falling edge in the RxD line. If a valid start bit is detected, then the rest of the bits are also
detected and shifted into the SBUF.
After shifting in 8 data bits, there is one more shift to do, after which the SBUF and RB8 are loaded and
RI is set. However certain conditions must be met before the loading and setting of RI can be done.
1. RI must be 0 and
2. Either SM2 = 0, or the received stop bit = 1.
If these conditions are met, then the stop bit goes to RB8, the 8 data bits go into SBUF and RI is set.
Otherwise the received frame may be lost. After the middle of the stop bit, the receiver goes back to
looking for a 1-to-0 transition on the RxD pin.
1/2
1/16
TX CLOCK
RX CLOCK
TI
RI
TX SHIFT
RX START
RX SHIFT
LOAD SBUF
SMOD
CLOCK
SIN D8
SBUF
Read SBUF
Internal
Data Bus
Serial
Controllor
CLOCK
LOAD
PARIN
TX START
Internal
Data Bus
Write to
SBUF SOUT
Transmit Shift Register
Serial Interrupt
TXD
RXD
PAROUT
RB8
START
STOP
0
1
BIT
DETECTOR
1-To-0
DETECTOR
SAMPLE
1/16
0
Timer 1
Overflow
1
Receive Shift Register
0 1
0 1
TCLK
RCLK
Timer 2
Overflow
Figure 15-2: Uart Serial Port Mode 1
15.3 Mode 2
This mode uses a total of 11 bits in asynchronous full-duplex communication. The functional
description is shown in the figure below. The frame consists of one start bit (0), 8 data bits (LSB first), a
programmable 9th bit (TB8) and a stop bit (0). The 9th bit received is put into RB8. The baud rate is
programmable to 1/32 or 1/64 of the oscillator frequency, which is determined by the SMOD bit in
n UVOTO n = fl $ 3? Jill {TM ¢ : 4* ‘_| W
Preliminary N79E352/N79E352R Data Sheet
Publication Release Date: Jul, 29, 2009
- 85 - Revision A06
PCON SFR. Transmission begins with a write to SBUF. The serial data is brought out on to TxD pin at
C1 following the first roll-over of the divide by 16 counter. The next bit is placed on TxD pin at C1
following the next rollover of the divide by 16 counter. Thus the transmission is synchronized to the
divide by 16 counter, and not directly to the write to SBUF signal. After all 9 bits of data are transmitted,
the stop bit is transmitted. The TI flag is set in the C1 state after the stop bit has been put out on TxD
pin. This will be at the 11th rollover of the divide by 16 counter after a write to SBUF. Reception is
enabled only if REN is high. The serial port actually starts the receiving of serial data, with the detection
of a falling edge on the RxD pin. The 1-to-0 detector continuously monitors the RxD line, sampling it at
the rate of 16 times the selected baud rate. When a falling edge is detected, the divide by 16 counter is
immediately reset. This helps to align the bit boundaries with the rollovers of the divide by 16 counter.
The 16 states of the counter effectively divide the bit time into 16 slices. The bit detection is done on a
best of three basis. The bit detector samples the RxD pin, at the 8th, 9th and 10th counter states. By
using a majority 2 of 3 voting system, the bit value is selected. This is done to improve the noise
rejection feature of the serial port.
TX CLOCK
RX CLOCK
TI
RI
TX SHIFT
RX START
RX SHIFT
LOAD SBUF
CLOCK
SIN D8
SBUF
Read SBUF
Internal
Data Bus
Serial
Controllor
CLOCK
LOAD
PARIN
TX START
Internal
Data Bus
Write to
SBUF SOUT
Transmit Shift Register
Serial Interrupt
TXD
RXD
PAROUT
RB 8
START
STOP
BIT
DETECTOR
1 - To - 0
DETECTOR
D8TB 8
Receive Shift Register
1 / 2
1 / 16
SMOD
SAMPLE
1 / 16
0
Fcpu/2
1
Figure 15-3: Uart Serial Port Mode 2
If the first bit detected after the falling edge of RxD pin, is not 0, then this indicates an invalid start bit,
and the reception is immediately aborted. The serial port again looks for a falling edge in the RxD line.
If a valid start bit is detected, then the rest of the bits are also detected and shifted into the SBUF. After
shifting in 9 data bits, there is one more shift to do, after which the SBUF and RB8 are loaded and RI is
set. However certain conditions must be met before the loading and setting of RI can be done.
1. RI must be 0 and
2. Either SM2 = 0, or the received stop bit = 1.
n UVOTO n
Preliminary N79E352/N79E352R Data Sheet
- 86 -
If these conditions are met, then the stop bit goes to RB8, the 8 data bits go into SBUF and RI is set.
Otherwise the received frame may be lost. After the middle of the stop bit, the receiver goes back to
looking for a 1-to-0 transition on the RxD pin.
n UVOTO n =
Preliminary N79E352/N79E352R Data Sheet
Publication Release Date: Jul, 29, 2009
- 87 - Revision A06
15.4 Mode 3
This mode is similar to Mode 2 in all respects, except that the baud rate is programmable. The user
must first initialize the Serial related SFR SCON before any communication can take place. This
involves selection of the Mode and baud rate. The Timer 1 should also be initialized if modes 1 and 3
are used. In all four modes, transmission is started by any instruction that uses SBUF as a destination
register. Reception is initiated in Mode 0 by the condition RI = 0 and REN = 1. This will generate a
clock on the TxD pin and shift in 8 bits on the RxD pin. Reception is initiated in the other modes by the
incoming start bit if REN = 1. The external device will start the communication by transmitting the start
bit.
TX CLOCK
RX CLOCK
TI
RI
TX SHIFT
RX START
RX SHIFT
LOAD SBUF
CLOCK
SIN D8
SBUF
Read SBUF
Internal
Data Bus
Serial
Controllor
CLOCK
LOAD
PARIN
TX START
Internal
Data Bus
Write to
SBUF SOUT
Transmit Shift Register
Serial Interrupt
TXD
RXD
PAROUT
RB8
START
STOP
0
1
BIT
DETECTOR
1-To-0
DETECTOR
D8TB8
Receive Shift Register
1/2
1/16
SMOD
SAMPLE
1/16
0
Timer 1
Overflow
1
0 1
0 1
TCLK
RCLK
Timer 2
Overflow
Figure 15-4: Uart Serial Port Mode 3
SM1 SM0 Mode Type Baud Clock Frame
Size Start
Bit Stop
Bit 9th bit
Function
0 0 0 Synch. 4 or 12 TCLKS 8 bits No No None
0 1 1 Asynch. Timer 1 or 2 10 bits 1 1 None
1 0 2 Asynch. 32 or 64 TCLKS 11 bits 1 1 0, 1
1 1 3 Asynch. Timer 1 or 2 11 bits 1 1 0, 1
Table 15-1: Uart Serial Port Modes
n UVOTO n
Preliminary N79E352/N79E352R Data Sheet
- 88 -
15.5 Framing Error Detection
A Frame Error occurs when a valid stop bit is not detected. This could indicate incorrect serial data
communication. Typically the frame error is due to noise and contention on the serial communication
line. The N79E352(R) has the facility to detect such framing errors and set a flag which can be
checked by software.
The Frame Error FE bit is located in SCON.7. This bit is normally used as SM0 in the standard 8051
family. However, in the N79E352(R) it serves a dual function and is called SM0/FE. There are actually
two separate flags, one for SM0 and the other for FE. The flag that is actually accessed as SCON.7 is
determined by SMOD0 (PCON.6) bit. When SMOD0 is set to 1, then the FE flag is indicated in
SM0/FE. When SMOD0 is set to 0, then the SM0 flag is indicated in SM0/FE.
The FE bit is set to 1 by hardware but must be cleared by software. Note that SMOD0 must be 1 while
reading or writing to FE. If FE is set, then any following frames received without any error will not clear
the FE flag. The clearing has to be done by software.
15.6 Multiprocessor Communications
Multiprocessor communications makes use of the 9th data bit in modes 2 and 3. In the N79E352(R),
the RI flag is set only if the received byte corresponds to the Given or Broadcast address. This
hardware feature eliminates the software overhead required in checking every received address, and
greatly simplifies the software programmer task.
In the multiprocessor communication mode, the address bytes are distinguished from the data bytes by
transmitting the address with the 9th bit set high. When the master processor wants to transmit a block
of data to one of the slaves, it first sends out the address of the targeted slave (or slaves). All the slave
processors should have their SM2 bit set high when waiting for an address byte. This ensures that they
will be interrupted only by the reception of a address byte. The Automatic address recognition feature
ensures that only the addressed slave will be interrupted. The address comparison is done in hardware
not software.
The addressed slave clears the SM2 bit, thereby clearing the way to receive data bytes. With SM2 = 0,
the slave will be interrupted on the reception of every single complete frame of data. The unaddressed
slaves will be unaffected, as they will be still waiting for their address. In Mode 1, the 9th bit is the stop
bit, which is 1 in case of a valid frame. If SM2 is 1, then RI is set only if a valid frame is received and
the received byte matches the Given or Broadcast address.
The Master processor can selectively communicate with groups of slaves by using the Given Address.
All the slaves can be addressed together using the Broadcast Address. The addresses for each slave
are defined by the SADDR and SADEN SFRs. The slave address is an 8-bit value specified in the
SADDR SFR. The SADEN SFR is actually a mask for the byte value in SADDR. If a bit position in
SADEN is 0, then the corresponding bit position in SADDR is don't care. Only those bit positions in
SADDR whose corresponding bits in SADEN are 1 are used to obtain the Given Address. This gives
the user flexibility to address multiple slaves without changing the slave address in SADDR.
n UVOTO n
Preliminary N79E352/N79E352R Data Sheet
Publication Release Date: Jul, 29, 2009
- 89 - Revision A06
The following example shows how the user can define the Given Address to address different slaves.
Slave 1:
SADDR 1010 0100
SADEN 1111 1010
Given 1010 0x0x
Slave 2:
SADDR 1010 0111
SADEN 1111 1001
Given 1010 0xx1
The Given address for slave 1 and 2 differ in the LSB. For slave 1, it is a don't care, while for slave 2 it
is 1. Thus to communicate only with slave 1, the master must send an address with LSB = 0 (1010
0000). Similarly the bit 1 position is 0 for slave 1 and don't care for slave 2. Hence to communicate only
with slave 2 the master has to transmit an address with bit 1 = 1 (1010 0011). If the master wishes to
communicate with both slaves simultaneously, then the address must have bit 0 = 1 and bit 1 = 0. The
bit 3 position is don't care for both the slaves. This allows two different addresses to select both slaves
(1010 0001 and 1010 0101).
The master can communicate with all the slaves simultaneously with the Broadcast Address. This
address is formed from the logical ORing of the SADDR and SADEN SFRs. The zeros in the result are
defined as don't cares In most cases the Broadcast Address is FFh. In the previous case, the
Broadcast Address is (1111111X) for slave 1 and (11111111) for slave 2.
The SADDR and SADEN SFRs are located at address A9h and B9h respectively. On reset, these two
SFRs are initialized to 00h. This results in Given Address and Broadcast Address being set as XXXX
XXXX(i.e. all bits don't care). This effectively removes the multiprocessor communications feature,
since any selectivity is disabled.
n UVOTO n =
Preliminary N79E352/N79E352R Data Sheet
- 90 -
16. I2C SERIAL PORT
The I2C bus uses two wires (SDA and SCL) to transfer information between devices connected to the
bus. The main features of the bus are:
Bidirectional data transfer between masters and slaves
Multimaster bus (no central master)
Arbitration between simultaneously transmitting masters without corruption of serial data on the bus
Serial clock synchronization allows devices with different bit rates to communicate via one serial bus
Serial clock synchronization can be used as a handshake mechanism to suspend and resume serial
transfer
The I2C bus may be used for test and diagnostic purposes
t
BUF
STOP
SDA
SCL
START
t
HD;STA
t
LOW
t
HD;DAT
t
HIGH
t
f
t
SU;DAT
Repeated
START
t
SU;STA
t
SU;STO
STOP
t
r
Figure 16-1: I2C Bus Timing
The device’s on-chip I2C logic provides the serial interface that meets the I2C bus standard mode
specification. The I2C logic handles bytes transfer autonomously. It also keeps track of serial transfers,
and a status register (I2STATUS) reflects the status of the I2C bus.
The I2C port, SCL and SDA are at P1.2 and P1.3. When the I/O pins are used as I2C port, user must
set the pins to logic high in advance. When I2C port is enabled by setting ENS to high, the internal
states will be controlled by I2CON and I2C logic hardware. Once a new status code is generated and
stored in I2STATUS, the I2C interrupt flag (SI) will be set automatically. If both EA and EI2C are also in
logic high, the I2C interrupt is requested. The 5 most significant bits of I2STATUS stores the internal
state code, the lowest 3 bits are always zero and the content keeps stable until SI is cleared by
software.
16.1 I2C Bus
The I2C bus is a serial I/O port, which supports all transfer modes from and to the I2C bus. The I2C
port handles byte transfers autonomously. To enable this port, the bit ENSI in I2CON should be set to
'1'. The CPU interfaces to the I2C port through the following six special function registers: I2CON
(control register, C0H), I2STATUS (status register, BDH), I2DAT (data register, BCH), I2ADDR
(address registers, C1H), I2CLK (clock rate register BEH) and I2TIMER (Timer counter register, BFH).
The H/W interfaces to the I2C bus via two pins: SDA (P1.2, serial data line) and SCL (P1.3, serial clock
line). Pull up resistor is needed for Pin P1.2 and P1.3 for I2C operation as these are 2 open drain pins
(on I2C mode).
n UVOTO n E
Preliminary N79E352/N79E352R Data Sheet
Publication Release Date: Jul, 29, 2009
- 91 - Revision A06
16.2 The I2C Control Registers:
The I2C has 1 control register (I2CON) to control the transmit/receive flow, 1 data register (I2DAT) to
buffer the Tx/Rx data, 1 status register (I2STATUS) to catch the state of Tx/Rx, recognizable slave
address register for slave mode use and 1 clock rate control block for master mode to generate the
variable baud rate.
16.2.1 The Address Registers, I2ADDR
I2C port is equipped with one slave address register. The contents of the register are irrelevant when
I2C is in master mode. In the slave mode, the seven most significant bits must be loaded with the
MCU’s own slave address. The I2C hardware will react if the contents of I2ADDR are matched with the
received slave address.
The I2C ports support the General Call function. If the GC bit is set the I2C port1 hardware will
respond to General Call address (00H). Clear GC bit to disable general call function.
When GC bit is set, the I2C is in Slave mode, it can be received the general call address by 00H after
Master send general call address to I2C bus, then it will follow status of GC mode. If it is in Master
mode, the AA bit must be cleared when it will send general call address of 00H to I2C bus.
16.2.2 The Data Register, I2DAT
This register contains a byte of serial data to be transmitted or a byte which has just been received.
The CPU can read from or write to this 8-bit directly addressable SFR while it is not in the process of
shifting a byte. This occurs when the bus is in a defined state and the serial interrupt flag (SI) is set.
Data in I2DAT remains stable as long as SI bit is set. While data is being shifted out, data on the bus is
simultaneously being shifted in; I2DAT always contains the last data byte present on the bus. Thus, in
the event of arbitration lost, the transition from master transmitter to slave receiver is made with the
correct data in I2DAT.
I2DAT and the acknowledge bit form a 9-bit shift register, the acknowledge bit is controlled by the
hardware and cannot be accessed by the CPU. Serial data is shifted through the acknowledge bit into
I2DAT on the rising edges of serial clock pulses on the SCL line. When a byte has been shifted into
I2DAT, the serial data is available in I2DAT, and the acknowledge bit (ACK or NACK) is returned by the
control logic during the ninth clock pulse. Serial data is shifted out from I2DAT on the falling edges of
SCL clock pulses, and is shifted into I2DAT on the rising edges of SCL clock pulses.
I2DAT.7 I2DAT.6 I2DAT.5 I2DAT.4 I2DAT.3 I2DAT.2 I2DAT.1 I2DAT.0
I2C Data Register:
shifting direction
n UVOTO n
Preliminary N79E352/N79E352R Data Sheet
- 92 -
16.2.3 The Control Register, I2CON
The CPU can read from and write to this 8-bit, directly addressable SFR. Two bits are affected by
hardware: the SI bit is set when the I2C hardware requests a serial interrupt, and the STO bit is cleared
when a STOP condition is present on the bus. The STO bit is also cleared when ENS = "0".
ENSI Set to enable I2C serial function block. When ENS=1 the I2C serial function enables. The
port latches of SDA1 and SCL1 must be set to logic high.
STA I2C START Flag. Setting STA to logic 1 to enter master mode, the I2C hardware sends a
START or repeat START condition to bus when the bus is free.
STO I2C STOP Flag. In master mode, setting STO to transmit a STOP condition to bus then
I2C hardware will check the bus condition if a STOP condition is detected this flag will be
cleared by hardware automatically. In a slave mode, setting STO resets I2C hardware to
the defined not addressed slave mode. This means it is NO LONGER in the slave
receiver mode to receive data from the master transmit device.
SI I2C Port 1 Interrupt Flag. When a new I2C bus state is present in the S1STA register, the
SI flag is set by hardware, and if the EA and EI2C1 bits are both set, the I2C1 interrupt is
requested. SI must be cleared by software.
AA Assert Acknowledge control bit. When AA=1 prior to address or data received, an
acknowledged (low level to SDA) will be returned during the acknowledge clock pulse on
the SCL line when 1.) A slave is acknowledging the address sent from master, 2.) The
receiver devices are acknowledging the data sent by transmitter. When AA=0 prior to
address or data received, a Not acknowledged (high level to SDA) will be returned during
the acknowledge clock pulse on the SCL line.
16.2.4 The Status Register, I2STATUS
I2STATUS is an 8-bit read-only register. The three least significant bits are always 0. The five most
significant bits contain the status code. There are 26 possible status codes. When I2STATUS contains
F8H, no serial interrupt is requested. All other I2STATUS values correspond to defined I2C bus states.
When each of these states is entered, a status interrupt is requested (SI = 1). A valid status code is
present in I2STATUS one machine cycle after SI is set by hardware and is still present one machine
cycle after SI has been reset by software.
16.2.5 The I2C Clock Baud Rate Bits, I2CLK
The data baud rate of I2C is determines by I2CLK register when I2C is in a master mode. It is not
important when I2C is in a slave mode. In the slave modes, I2C will automatically synchronize with any
clock frequency up to 400 KHz from master I2C device.
The data baud rate of I2C setting is Data Baud Rate of I2C = Fcpu / (I2CLK+1). The Fcpu=Fosc/4. If
Fosc = 16MHz, the I2CLK = 40(28H), so data baud rate of I2C = 16MHz/(4X (40 +1)) = 97.56Kbits/sec.
The block diagram is as below figure.
n UVOTO n
Preliminary N79E352/N79E352R Data Sheet
Publication Release Date: Jul, 29, 2009
- 93 - Revision A06
16.2.6 I2C Time-out Counter, I2Timerx
The I2C logic block provides a 14-bit timer-out counter that helps user to deal with bus pending
problem. When SI is cleared user can set ENTI=1 to start the time-out counter. If I2C bus is pended
too long to get any valid signal from devices on bus, the time-out counter overflows cause TIF=1 to
request an I2C interrupt. The I2C interrupt is requested in the condition of either SI=1 or TIF=1. Flags
SI and TIF must be cleared by software.
1
0
Fcpu
1/4
14-bits Counter TIF
Clear Counter
ENTI
SI
DIV4
ENS1
To I2C Interrupt
Enable
SI
Figure 16-2: I2C Timer Count Block Diagram
16.3 Modes of Operation
The on-chip I2C ports support five operation modes, Master transmitter, Master receiver, Slave
transmitter, Slave receiver, and GC call.
In a given application, I2C port may operate as a master or as a slave. In the slave mode, the I2C port
hardware looks for its own slave address and the general call address. If one of these addresses is
detected, and if the slave is willing to receive or transmit data from/to master(by setting the AA bit),
acknowledge pulse will be transmitted out on the 9th clock, hence an interrupt is requested on both
master and slave devices if interrupt is enabled. When the microcontroller wishes to become the bus
master, the hardware waits until the bus is free before the master mode is entered so that a possible
slave action is not interrupted. If bus arbitration is lost in the master mode, I2C port switches to the
slave mode immediately and can detect its own slave address in the same serial transfer.
16.3.1 Master Transmitter Mode
Serial data output through SDA while SCL outputs the serial clock. The first byte transmitted contains
the slave address of the receiving device (7 bits) and the data direction bit. In this case the data
direction bit (R/W) will be logic 0, and it is represented by “W” in the flow diagrams. Thus the first byte
transmitted is SLA+W. Serial data is transmitted 8 bits at a time. After each byte is transmitted, an
acknowledge bit is received. START and STOP conditions are output to indicate the beginning and the
end of a serial transfer.
16.3.2 Master Receiver Mode
In this case the data direction bit (R/W) will be logic 1, and it is represented by “R” in the flow diagrams.
Thus the first byte transmitted is SLA+R. Serial data is received via SDA while SCL outputs the serial
clock. Serial data is received 8 bits at a time. After each byte is received, an acknowledge bit is
transmitted. START and STOP conditions are output to indicate the beginning and end of a serial
transfer.
n UVOTO n E
Preliminary N79E352/N79E352R Data Sheet
- 94 -
16.3.3 Slave Receiver Mode
Serial data and the serial clock are received through SDA and SCL. After each byte is received, an
acknowledge bit is transmitted. START and STOP conditions are recognized as the beginning and end
of a serial transfer. Address recognition is performed by hardware after reception of the slave address
and direction bit.
16.3.4 Slave Transmitter Mode
The first byte is received and handled as in the slave receiver mode. However, in this mode, the
direction bit will indicate that the transfer direction is reversed. Serial data is transmitted via SDA while
the serial clock is input through SCL. START and STOP conditions are recognized as the beginning
and end of a serial transfer.
16.4 Data Transfer Flow in Five Operating Modes
The five operating modes are: Master/Transmitter, Master/Receiver, Slave/Transmitter, Slave/Receiver
and GC Call. Bits STA, STO and AA in I2CON register will determine the next state of the I2C
hardware after SI flag is cleared. Upon complexion of the new action, a new status code will be
updated and the SI flag will be set. If the I2C interrupt control bits (EA and EI2) are enable, appropriate
action or software branch of the new status code can be performed in the Interrupt service routine.
Data transfers in each mode are shown in the following figures.
*** Legend for the following five figures:
08H
A START has been
transmitted.
(STA,STO,SI,AA)=(0,0,0,X)
SLA+W will be transmitted;
ACK bit will be received.
18H
SLA+W has been transmitted;
ACK has been received.
Last state
Last action is done
Next setting in S1CON
Expected next action
next action is done
New state
Software's access to S1DAT with respect to "Expected next action":
Software should load the data byte (to be transmitted)
into S1DAT before new S1CON setting is done.
(1) Data byte will be transmitted:
(2) SLA+W (R) will be transmitted:
Software should load the SLA+W/R (to be transmitted)
into S1DAT before new S1CON setting is done.
(3) Data byte will be received:
Software can read the received data byte from S1DAT
while a new state is entered.
Figure 16-3: Legen for the following four figures
n UVOTO n = H i i i l i ‘l ‘1 l: J ._ ;
Preliminary N79E352/N79E352R Data Sheet
Publication Release Date: Jul, 29, 2009
- 95 - Revision A06
08H
A START has been
transmitted.
(STA,STO,SI,AA)=(0,0,0,X)
SLA+W will be transmitted;
ACK bit will be received.
Set STA to generate
a START.
18H
SLA+W will be transmitted;
ACK bit will be received.
or
20H
SLA+W will be transmitted;
NOT ACK bit will be received.
(STA,STO,SI,AA)=(1,0,0,X)
A repeated START will be transmitted;
(STA,STO,SI,AA)=(0,0,0,X)
Data byte will be transmitted;
ACK will be received.
(STA,STO,SI,AA)=(0,1,0,X)
A STOP will be transmitted;
STO flag will be reset.
Send a STOP
(STA,STO,SI,AA)=(1,1,0,X)
A STOP followed by a START will
be transmitted;
STO flag will be reset.
Send a STOP
followed by a START
28H
Data byte in S1DAT has been transmitted;
ACK has been received.
or
30H
Data byte in S1DAT has been transmitted;
NOT ACK has been received.
10H
A repeated START has
been transmitted.
(STA,STO,SI,AA)=(0,0,0,X)
SLA+R will be transmitted;
ACK bit will be transmitted;
SIO1 will be switched to MST/REC mode.
38H
Arbitration lost in SLA+R/W or
Data byte.
(STA,STO,SI,AA)=(0,0,0,X)
I2C bus will be release;
Not address SLV mode will be entered.
(STA,STO,SI,AA)=(1,0,0,X)
A START will be transmitted when the
bus becomes free.
Send a START
when bus becomes free
Enter NAslave
From Slave Mode (C)
To Master/Receiver (A)
From Master/Receiver (B)
Figure 16-4: Master Transmitter Mode
n UVOTO n
Preliminary N79E352/N79E352R Data Sheet
- 96 -
08H
A START has been
transmitted.
(STA,STO,SI,AA)=(0,0,0,X)
SLA+R will be transmitted;
ACK bit will be received.
Set STA to generate
a START.
40H
SLA+R has been transmitted;
ACK has been received.
(STA,STO,SI,AA)=(0,1,0,X)
A STOP will be transmitted;
STO flag will be reset.
(STA,STO,SI,AA)=(1,1,0,X)
A STOP followed by a START will
be transmitted;
STO flag will be reset.
(STA,STO,SI,AA)=(0,0,0,0)
Data byte will be received;
NOT ACK will be returned.
Send a STOP
(STA,STO,SI,AA)=(0,0,0,1)
Data byte will be received;
ACK will be returned.
10H
A repeated START has
been transmitted.
(STA,STO,SI,AA)=(0,0,0,X)
SLA+R will be transmitted;
ACK bit will be transmitted;
SIO1 will be switched to MST/REC mode.
(STA,STO,SI,AA)=(1,0,0,X)
A START will be transmitted;
when the bus becomes free
(STA,STO,SI,AA)=(0,0,0,X)
I2C bus will be release;
Not address SLV mode will be entered.
Enter NAslave
From Master/Transmitter (A)
To Master/Transmitter (B)
From Slave Mode (C)
48H
SLA+R has been transmitted;
NOT ACK has been received.
58H
Data byte has been received;
NOT ACK has been returned.
50H
Data byte has been received;
ACK has been returned.
Send a STOP
followed by a START
38H
Arbitration lost in NOT ACK
bit.
Send a START
when bus becomes free
(STA,STO,SI,AA)=(1,0,0,X)
A repeated START will be transmitted;
Figure 16-5: Master Receiver Mode
n UVOTO n i i i [if \ i ,7: ‘ K; i
Preliminary N79E352/N79E352R Data Sheet
Publication Release Date: Jul, 29, 2009
- 97 - Revision A06
Set AA
A8H
Own SLA+R has been received;
ACK has been return.
or
B0H
Arbitration lost SLA+R/W as master;
Own SLA+R has been received;
ACK has been return.
(STA,STO,SI,AA)=(1,0,0,1)
Switch to not address SLV mode;
Own SLA will be recognized;
A START will be transmitted when the
bus becomes free.
(STA,STO,SI,AA)=(0,0,0,0)
Last data will be transmitted;
ACK will be received.
(STA,STO,SI,AA)=(0,0,0,1)
Data byte will be transmitted;
ACK will be received.
Send a START
when bus becomes free
C8H
Last data byte in S1DAT has been transmitted;
ACK has been received.
(STA,STO,SI,AA)=(1,0,0,0)
Switch to not addressed SLV mode;
No recognition of own SLA;
A START will be transmitted when the
becomes free.
(STA,STO,SI,AA)=(0,0,0,1)
Switch to not addressed SLV mode;
Own SLA will be recognized.
(STA,STO,SI,AA)=(0,0,0,0)
Switch to not addressed SLV mode;
No recognition of own SLA.
Enter NAslave
To Master Mode (C)
(STA,STO,SI,AA)=(0,0,0,0)
Last data byte will be transmitted;
ACK will be received.
(STA,STO,SI,AA)=(0,0,0,1)
Data byte will be transmitted;
ACK will be received.
C0H
Data byte or Last data byte in S1DAT has been
transmitted;
NOT ACK has been received.
B8H
Data byte in S1DAT has been transmitted;
ACK has been received.
A0H
A STOP or repeated START has been
received while still addressed as SLV/TRX.
Figure 16-6: Slave Transmitter Mode
n UVOTO n = if ‘77J [ I l 1 \, l J /
Preliminary N79E352/N79E352R Data Sheet
- 98 -
Set AA
60H
Own SLA+W has been received;
ACK has been return.
or
68H
Arbitration lost SLA+R/W as master;
Own SLA+W has been received;
ACK has been return.
(STA,STO,SI,AA)=(1,0,0,1)
Switch to not address SLV mode;
Own SLA will be recognized;
A START will be transmitted when
the bus becomes free.
(STA,STO,SI,AA)=(0,0,0,0)
Data will be received;
NOT ACK will be returned.
(STA,STO,SI,AA)=(0,0,0,1)
Data will be received;
ACK will be returned.
Send a START
when bus becomes free
88H
Previously addressed with own SLA address;
NOT ACK has been returned.
(STA,STO,SI,AA)=(1,0,0,0)
Switch to not addressed SLV mode;
No recognition of own SLA;
A START will be transmitted when the
becomes free.
(STA,STO,SI,AA)=(0,0,0,1)
Switch to not addressed SLV mode;
Own SLA will be recognized.
(STA,STO,SI,AA)=(0,0,0,0)
Switch to not addressed SLV mode;
No recognition of own SLA.
Enter NAslave
To Master Mode (C)
(STA,STO,SI,AA)=(0,0,0,0)
Data byte will be received;
NOT ACK will be returned.
(STA,STO,SI,AA)=(0,0,0,1)
Data byte will be received;
ACK will be returned.
80H
Previously addressed with own SLA address;
Data has been received;
ACK has been returned.
A0H
A STOP or repeated START has been
received while still addressed as SLV/REC.
Figure 16-7: Slave Receiver Mode
n UVOTO n =
Preliminary N79E352/N79E352R Data Sheet
Publication Release Date: Jul, 29, 2009
- 99 - Revision A06
Set AA
70H
Reception of the general call address
and one or more data bytes;
ACK has been return.
or
78H
Arbitration lost SLA+R/W as master;
and address as SLA by general call;
ACK has been return.
(STA,STO,SI,AA)=(1,0,0,1)
Switch to not address SLV mode;
Own SLA will be recognized;
A START will be transmitted when
the bus becomes free.
(STA,STO,SI,AA)=(X,0,0,0)
Data will be received;
NOT ACK will be returned.
(STA,STO,SI,AA)=(X,0,0,1)
Data will be received;
ACK will be returned.
Send a START
when bus becomes free
98H
Previously addressed with General Call;
Data byte has been received;
NOT ACK has been returned.
(STA,STO,SI,AA)=(1,0,0,0)
Switch to not addressed SLV mode;
No recognition of own SLA;
A START will be transmitted when the
becomes free.
(STA,STO,SI,AA)=(0,0,0,1)
Switch to not addressed SLV mode;
Own SLA will be recognized.
(STA,STO,SI,AA)=(0,0,0,0)
Switch to not addressed SLV mode;
No recognition of own SLA.
Enter NAslave
To Master Mode (C)
(STA,STO,SI,AA)=(X,0,0,0)
Data byte will be received;
NOT ACK will be returned.
(STA,STO,SI,AA)=(X,0,0,1)
Data byte will be received;
ACK will be returned.
90H
Previously addressed with General Call;
Data has been received;
ACK has been returned.
A0H
A STOP or repeated START has been
received while still addressed as
SLV/REC.
Figure 16-8: GC Mode
n UVOTO n
Preliminary N79E352/N79E352R Data Sheet
- 100 -
17. TIMED ACCESS PROTECTION
The N79E352(R) has several new features, like the Watchdog timer, on-chip ROM size adjustment,
wait state control signal and Power on/fail reset flag, which are crucial to proper operation of the
system. If left unprotected, errant code may write to the Watchdog control bits resulting in incorrect
operation and loss of control. In order to prevent this, the N79E352(R) has a protection scheme which
controls the write access to critical bits. This protection scheme is done using a timed access.
In this method, the bits which are to be protected have a timed write enable window. A write is
successful only if this window is active, otherwise the write will be discarded. This write enable window
is open for 3 machine cycles if certain conditions are met. After 3 machine cycles, this window
automatically closes. The window is opened by writing AAh and immediately 55h to the Timed
Access(TA) SFR. This SFR is located at address C7h. The suggested code for opening the timed
access window is
TA REG 0C7h ; define new register TA, located at 0C7h
MOV TA, #0AAh
MOV TA, #055h
When the software writes AAh to the TA SFR, a counter is started. This counter waits for 3 machine
cycles looking for a write of 55h to TA. If the second write (55h) occurs within 3 machine cycles of the
first write (AAh), then the timed access window is opened. It remains open for 3 machine cycles, during
which the user may write to the protected bits. Once the window closes the procedure must be
repeated to access the other protected bits.
Examples of Timed Assessing are shown below
Example 1: Valid access
MOV TA, #0AAh 3 M/C Note: M/C = Machine Cycles
MOV TA, #055h 3 M/C
MOV WDCON, #00h 3 M/C
Example 2: Valid access
MOV TA, #0AAh 3 M/C
MOV TA, #055h 3 M/C
NOP 1 M/C
SETB EWRST 2 M/C
Example 3: Valid access
MOV TA, #0Aah 3 M/C
MOV TA, #055h 3 M/C
ORL WDCON, #00000010B 3M/C
Example 4: Invalid access
MOV TA, #0AAh 3 M/C
MOV TA, #055h 3 M/C
NOP 1 M/C
NOP 1 M/C
CLR POR 2 M/C
Example 5: Invalid Access
MOV TA, #0AAh 3 M/C
NOP 1 M/C
n UVOTO n
Preliminary N79E352/N79E352R Data Sheet
Publication Release Date: Jul, 29, 2009
- 101 - Revision A06
MOV TA, #055h 3 M/C
SETB EWRST 2 M/C
In the first two examples, the writing to the protected bits is done before the 3 machine cycle window
closes. In Example 3, however, the writing to the protected bit occurs after the window has closed, and
so there is effectively no change in the status of the protected bit. In Example 4, the second write to TA
occurs 4 machine cycles after the first write, therefore the timed access window in not opened at all,
and the write to the protected bit fails.
n UVOTO n =
Preliminary N79E352/N79E352R Data Sheet
- 102 -
18. INTERRUPTS
N79E352(R) has four priority level interrupts structure with 11 interrupt sources. Each of the interrupt
sources has an individual priority bit, flag, interrupt vector and enable bit. In addition, the interrupts can
be globally enabled or disabled.
18.1 Interrupt Sources
The External Interrupts
INT0
and
INT1
can be either edge triggered or level triggered, programmable
through bits IT0 and IT1 (SFR TCON). The bits IE0 and IE1 in TCON register are the flags which are
checked to generate the interrupt. In the edge triggered mode, the INTx inputs are sampled in every
machine cycle. If the sample is high in one cycle and low in the next, then a high to low transition is
detected and the interrupts request flag IEx in TCON is set. The flag bit requests the interrupt. Since
the external interrupts are sampled every machine cycle, they have to be held high or low for at least
one complete machine cycle. The IEx flag is automatically cleared when the service routine is called. If
the level triggered mode is selected, then the requesting source has to hold the pin low till the interrupt
is serviced. The IEx flag will not be cleared by the hardware on entering the service routine. If the
interrupt continues to be held low even after the service routine is completed, then the processor may
acknowledge another interrupt request from the same source.
The Timer 0 and 1 Interrupts are generated by the TF0 and TF1 flags. These flags are set by the
overflow in the Timer 0 and Timer 1. The TF0 and TF1 flags are automatically cleared by the hardware
when the timer interrupt is serviced. The Watchdog timer can be used as a system monitor or a simple
timer. In either case, when the time-out count is reached, the Watchdog Timer interrupt flag WDIF
(WDCON.3) is set. If the interrupt is enabled by the enable bit EIE.4, then an interrupt will occur.
The timer 2 interrupt is generated through TF2 (timer 2 overflow/compare match). The hardware does
not clear these flags when a timer 2 interrupt is executed.
The uart serial block can generate interrupt on reception or transmission. There are two interrupt
sources from the uart block, which are obtained by the RI and TI bits in the SCON SFR. These bits are
not automatically cleared by the hardware, and the user will have to clear these bits using software.
This device also provide an independent I2C serial port. When new I2C state is present in I2STATUS,
the SI flag is set by hardware, and if EA and EI2 bits are both set, the I2C interrupt is requested. SI
must be cleared by software.
Keyboard interrupt is generated when any of the keypad connected to P0 pins is pressed. Each keypad
interrupt can be individually enabled or disabled. User will have to software clear the flag bit.
The input capture 0 interrupt is generated through CPTF0 flag. CPTF0 flag is set by input capture
events. The hardware does not clear this flag when the capture interrupt is executed. Software has to
clear the flag.
Brownout detect can cause brownout flag, BOF, to be asserted if power voltage drop below brownout
voltage level. Interrupt will occur if BOI (AUXR1.5), EBO (EIE.6) and global interrupt enable are set.
Source Vector Address Source Vector Address
External Interrupt 0 0003H Timer 0 Overflow 000BH
External Interrupt 1 0013H Timer 1 Overflow 001BH
Serial Port 0023H Brownout Interrupt 002BH
I2C Interrupt 0033H KBI Interrupt 003BH
Timer 2 Overflow 0043H - 004BH
Watchdog Timer 0053H - 005BH
n UVOTO n E
Preliminary N79E352/N79E352R Data Sheet
Publication Release Date: Jul, 29, 2009
- 103 - Revision A06
0063H Input Capture 0 Interrupt 006BH
Table 18- 1: N79E352(R) interrupt vector table
18.2 Priority Level Structure
There are four priority levels for the interrupts, highest, high, low and lowest. The interrupt sources can
be individually set to either high or low levels. Naturally, a higher priority interrupt cannot be interrupted
by a lower priority interrupt. However there exists a pre-defined hierarchy amongst the interrupts
themselves. This hierarchy comes into play when the interrupt controller has to resolve simultaneous
requests having the same priority level. This hierarchy is defined as shown on Table 18- 2: Four-level
interrupts priority.
The interrupt flags are sampled every machine cycle. In the same machine cycle, the sampled
interrupts are polled and their priority is resolved. If certain conditions are met then the hardware will
execute an internally generated LCALL instruction which will vector the process to the appropriate
interrupt vector address. The conditions for generating the LCALL are;
1. An interrupt of equal or higher priority is not currently being serviced.
2. The current polling cycle is the last machine cycle of the instruction currently being execute.
3. The current instruction does not involve a write to IE, EIE, IP0, IP0H, IP1 or IPH1 registers and is not
a RETI.
If any of these conditions are not met, then the LCALL will not be generated. The polling cycle is
repeated every machine cycle, with the interrupts sampled in the same machine cycle. If an interrupt
flag is active in one cycle but not responded to, and is not active when the above conditions are met,
the denied interrupt will not be serviced. This means that active interrupts are not remembered; every
polling cycle is new.
The processor responds to a valid interrupt by executing an LCALL instruction to the appropriate
service routine. This may or may not clear the flag which caused the interrupt. In case of Timer
interrupts, the TF0 or TF1 flags are cleared by hardware whenever the processor vectors to the
appropriate timer service routine. In case of external interrupt, /INT0 and /INT1, the flags are cleared
only if they are edge triggered. In case of Serial interrupts, the flags are not cleared by hardware. In the
case of Timer 2 interrupt, the flags are not cleared by hardware. The Watchdog timer interrupt flag
WDIF has to be cleared by software. The hardware LCALL behaves exactly like the software LCALL
instruction. This instruction saves the Program Counter contents onto the Stack, but does not save the
Program Status Word PSW. The PC is reloaded with the vector address of that interrupt which caused
the LCALL. These address of vector for the different sources are as shown on Table 18- 3: Summary
of interrupt sources. The vector table is not evenly spaced; this is to accommodate future expansions
to the device family.
Execution continues from the vectored address till an RETI instruction is executed. On execution of the
RETI instruction the processor pops the Stack and loads the PC with the contents at the top of the
stack. The user must take care that the status of the stack is restored to what it was after the hardware
LCALL, if the execution is to return to the interrupted program. The processor does not notice anything
if the stack contents are modified and will proceed with execution from the address put back into PC.
Note that a RET instruction would perform exactly the same process as a RETI instruction, but it would
not inform the Interrupt Controller that the interrupt service routine is completed, and would leave the
controller still thinking that the service routine is underway.
N79E352(R) uses a four priority level interrupt structure. This allows great flexibility in controlling the
handling of the interrupt sources.
n UVOTO n =
Preliminary N79E352/N79E352R Data Sheet
- 104 -
PRIORITY BITS INTERRUPT PRIORITY LEVEL
IPXH IPX
0 0 Level 0 (lowest priority)
0 1 Level 1
1 0 Level 2
1 1 Level 3 (highest priority)
Table 18- 2: Four-level interrupts priority
Each interrupt source can be individually enabled or disabled by setting or clearing a bit in registers IE
or EIE. The IE register also contains a global disable bit, EA, which disables all interrupts at once.
Each interrupt source can be individually programmed to one of four priority levels by setting or
clearing bits in the IP0, IP0H, IP1, and IP1H registers. An interrupt service routine in progress can be
interrupted by a higher priority interrupt, but not by another interrupt of the same or lower priority. The
highest priority interrupt service cannot be interrupted by any other interrupt source. So, if two requests
of different priority levels are received simultaneously, the request of higher priority level is serviced.
If requests of the same priority level are received simultaneously, an internal polling sequence
determines which request is serviced. This is called the arbitration ranking. Note that the arbitration
ranking is only used to resolve simultaneous requests of the same priority level.
Table below summarizes the interrupt sources, flag bits, vector address, enable bits, priority bits,
arbitration ranking, and whether each interrupt may wake up the CPU from Power Down mode.
Source Flag Vector
address Enable
bit Flag
cleared by Priority
bit Arbitration
ranking Power-
down
wakeup
External
Interrupt 0 IE0 0003H
EX0
(IE.0) Hardware,
Software
IP0H.0,
IP0.0 1(highest) Yes
Brownout
Detect BOF 002BH
EBO
(EIE.6) Hardware
IP1H.6,
IP1.6 2 Yes
Watchdog
Timer WDIF 0053H EWDI
(EIE.4) Software IP1H.4,
IP1.4 3 Yes
Timer 0
Overflow TF0 000BH
ET0
(IE.1) Hardware,
Software
IP0H.1,
IP0.1 4 No
I2C
Interrupt SI + TIF 0033h
EI2
(EIE.0) Software
IP1H.0,
IP1.0 5 No
External
Interrupt 1 IE1 0013H EX1
(IE.2) Hardware,
Software
IP0H.2,
IP0.2 6 Yes
KBI KBF 003BH
EKB
(EIE.1)
Software
IP1H.1,
IP1.1
7 Yes
Timer 1
Overflow TF1 001BH
ET1
(IE.3) Hardware,
Software
IP0H.3,
IP0.3 8 No
UART RI + TI 0023H
ES
(IE.4)
Software
IP0H.4,
IP0.4
9 No
n UVOTO n =
Preliminary N79E352/N79E352R Data Sheet
Publication Release Date: Jul, 29, 2009
- 105 - Revision A06
Timer 2
Overflow/
Match
TF2 + EXF2 0043H
ET2
(IE.5) Software
IP0H.5,
IP0.5 10 No
Input
Capture CPTF0 006BH
ECPTF
(EIE.7) Software
IP1H.7,
IP1.7 11 No
Table 18- 3: Summary of interrupt sources
Note: 1. The Watchdog Timer can wake up Power Down Mode when its clock source is used internal RC.
18.3 Interrupt Response Time
The response time for each interrupt source depends on several factors, such as the nature of the
interrupt and the instruction underway. In the case of external interrupts
INT0
to
INT1
, they are
sampled at C3 of every machine cycle and then their corresponding interrupt flags IEx will be set or
reset. The Timer 0 and 1 overflow flags are set at C3 of the machine cycle in which overflow has
occurred. These flag values are polled only in the next machine cycle. If a request is active and all
three conditions are met, then the hardware generated LCALL is executed. This LCALL itself takes
four machine cycles to be completed. Thus there is a minimum time of five machine cycles between
the interrupt flag being set and the interrupt service routine being executed.
A longer response time should be anticipated if any of the three conditions are not met. If a higher or
equal priority is being serviced, then the interrupt latency time obviously depends on the nature of the
service routine currently being executed. If the polling cycle is not the last machine cycle of the
instruction being executed, then an additional delay is introduced. The maximum response time (if no
other interrupt is in service) occurs if the device is performing a write to IE, EIE, IP0, IP0H, IP1 or IP1H
and then executes a MUL or DIV instruction. From the time an interrupt source is activated, the longest
reaction time is 12 machine cycles. This includes 1 machine cycle to detect the interrupt, 2 machine
cycles to complete the IE, EIE, IP0, IP0H, IP1 or IP1H access, 5 machine cycles to complete the MUL
or DIV instruction and 4 machine cycles to complete the hardware LCALL to the interrupt vector
location.
Thus in a single-interrupt system the interrupt response time will always be more than 5 machine
cycles and not more than 12 machine cycles. The maximum latency of 12 machine cycle is 48 clock
cycles. Note that in the standard 8051 the maximum latency is 8 machine cycles which equals 96
machine cycles. This is a 50% reduction in terms of clock periods.
18.4 Interrupt Inputs
N79E352(R) has two individual interrupt inputs as well as the Keyboard Interrupt function. The latter is
described separately elsewhere in this section. Two interrupt inputs are identical to those present on
the standard 80C51 microcontroller.
The external sources can be programmed to be level-activated or transition-activated by setting or
clearing bit IT1 or IT0 in Register TCON. If ITn = 0, external interrupt n is triggered by a detected low at
the INTn pin. If ITn = 1, external interrupt n is edge triggered. In this mode if successive samples of the
/INTn pin show a high in one cycle and a low in the next cycle, interrupt request flag IEn in TCON is
set, causing an interrupt request.
Since the external interrupt pins are sampled once each machine cycle, an input high or low should
hold for at least 6 CPU Clocks to ensure proper sampling. If the external interrupt is high for at least
one machine cycle, and then hold it low for at least one machine cycle. This is to ensure that the
n UVOTO n ,, 4 , \P/ /, \J/ / \ /
Preliminary N79E352/N79E352R Data Sheet
- 106 -
transition is seen and that interrupt request flag IEn is set. IEn is automatically cleared by the CPU
when the service routine is called.
If the external interrupt is level-activated, the external source must hold the request active until the
requested interrupt is actually generated. If the external interrupt is still asserted when the interrupt
service routine is completed another interrupt will be generated. It is not necessary to clear the interrupt
flag IEn when the interrupt is level sensitive, it simply tracks the input pin level.
If an external interrupt is enabled when the device is put into Power Down or Idle mode, the interrupt
will cause the processor to wake up and resume operation. Refer to the section on Power
Management for details.
EI2
ES
RI + TI
ET1
TF1
ET0
TF0
EA
IE0
IE1
BOF
KBF
WDIF
EWDI
EKB
EBO
EX1
EX0
Interrupt
to CPU
Wakeup
(If in Power Down)
ET2
TF2
ECPTF
CPTF0
SI
Figure 18- 1: Interrupt inputs
19. KEYBOARD FUNCTION
The N79E352(R) provideds 8 keyboard interrupt function to detect keypad status which key is acted,
and allow a single interrupt to be generated when any key is pressed on a keyboard or keypad
n UVOTO n
Preliminary N79E352/N79E352R Data Sheet
Publication Release Date: Jul, 29, 2009
- 107 - Revision A06
connected to specific pins of the N79E352(R), as shown below figure. This interrupt may be used to
wake up the CPU from Idle or Power Down modes, after chip is in Power Down or Idle Mode.
Keyboard function is supported through by Port 0. It can allow any or all pins of Port 0 to be enabled to
cause this interrupt. Port pins are enabled by the setting of bits of KBI0 ~ KBI7 in the KBI register, as
shown below figure. The Keyboard Interrupt Flag (KBF) in the AUXR1 register is set when any enabled
pin is triggered while the KBI interrupt function is active, and the low pulse must be more than 1
machine cycle, an interrupt will be generated if it has been enabled. The KBF bit set by hardware and
must be cleared by software. In order to determine which key was pressed, the KBI will allow the
interrupt service routine to poll port 0.
The N79E352(R) has addition SFR KBL level configuration register to control either a low or high level
trigger.
P0.7
KBI.0
KBI.1
KBI.2
KBI.3
KBI.4
KBI.5
KBI.6
KBI.7
EKB
(From EIE Register)
KBF (KBI
Interrupt)
High/low
level
KBL.7
P0.6 High/low
level
KBL.6
P0.5 High/low
level
KBL.5
P0.4 High/low
level
KBL.4
P0.3 High/low
level
KBL.3
P0.2 High/low
level
KBL.2
P0.1 High/low
level
KBL.1
P0.0 High/low
level
KBL.0
Figure 19-1: KBI inputs
n UVOTO n
Preliminary N79E352/N79E352R Data Sheet
- 108 -
20. INPUT CAPTURE
The input capture modules are function to detect/measure pulse width and period of a square wave. It
supports one capture inputt with digital noise rejection filter. The modules are configured by
CAPCON0, CAPCON1 and T2MOD SFR registers. Input Capture has its own edge detector but share
with Timer 0. The Input Capture is a schmitt trigger pin. For this operation it basically consists of;
Capture module function block
Timer 0 (mode 0 and 1) block
The capture module block consists of 2 bytes capture registers, noise filter and programmable edge
triggers. Noise Filter is used to filter the unwanted glitch or pulse on the trigger input pin. The noise
filter can be enabled through bit ENF0 (CAPCON1). If enabled, the capture logic required to sample 4
consecutive same capture input value in order to recognize an edge as a capture event. A possible
implementation of digital noise filter is as follow;
Q
Q
SET
CLR
D
Q
Q
SET
CLR
D
Q
Q
SET
CLR
D
Q
Q
SET
CLR
D
J
Q
Q
K
SET
CLR
Tx filtered
Clk
Tx
Figure 20-1: Noise filter
The interval between pulses requirement for input capture is 1 machine cycle width, which is the same
as the pulse width required to guarantee a trigger for all trigger edge mode. For less than 3 system
clocks, anything less than 3 clocks will not have any trigger and pulse width of 3 or more but less than
4 clocks will trigger but will not guarantee 100% because input sampling is at stage C3 of the machine
cycle.
The trigger option is programmable through CCT0[1:0] (CAPCON0[3:2]). It supports positive edge,
negative edge and both edge triggers. The capture module consists of an enable, ICEN0 (T2MOD.4).
Timer/Counter 0 needs to be configured as mode 0 or 1 recommanded. It’s content will transfer to
CCL0 and CCH0 SFR when CPTF0 is set. If ICEN0 is enabled, each time the external pin trigger, the
content TL0 and TH0 (from Timer 0 block) will be captured/transferred into the capture registers, CCL0
and CCH0, depending which external pin trigger. This action also causes the CPTF0 flag bit in
CAPCON1 to be set, which will also generate an interrupt (if enabled by ECPTF bit in SFR EIE.7). The
flag is set by hardware and cleared by software.
Setting the T0CC bit (CAPCON1.6), will allow hardware to reset timer 0 automatically after the value of
TL0 and TH0 have been captured.
n UVOTO n # %#%
Preliminary N79E352/N79E352R Data Sheet
Publication Release Date: Jul, 29, 2009
- 109 - Revision A06
Noise
Filter
CCL 0 CCH 0
Capture 0 Block
[00 ]
[01 ]
[10 ]
T0
(P3.4)
CAPCON0.CCT0.1~0
Edge Select
CAPCON1.ENF0
With
Schmitt
Trigger
CPTF0
Timer 0
(recommanded mode 0 or 1)
CAPCON1.T0CC
(Timer 0 count clear enable)
T2MOD.ICEN0
Figure 20-2: Input capture block
n UVOTO n =
Preliminary N79E352/N79E352R Data Sheet
- 110 -
21. PULSE WIDTH MODULATED OUTPUTS (PWM)
The N79E352(R) contains two Pulse Width Modulated (PWM) channels which generate pulses of
programmable length and interval. The output for PWM0 is on P1.4 and PWM1 on P1.5. After chip
reset the internal output of the each PWM channel is a “1” (if PRHI=1). The PWM block diagram is
shown as below figure. The interval between successive outputs is controlled by a 8bit up-counter
which uses the selectable clock sources. The clock sources supported are cpu clock, timer 0 overflow
and timer 1 overflow, selectable by PWMCON3.PCLK.1~0 bits. The clock sources can be further
divided with programmable PWMCON3.FP1~0 bits. When the counter reaches overflow, it is reloaded
with zero.
The width of each PWM output pulse is determined by the value in the appropriate Compare registers,
PWMnL (n=0,1). When the counter described above matches compare register value the PWM output
is forced low. It remains low until the counter value overflow. The number of clock pulses that the
PWMn output is low is given by:
tLO = (FFh PWMn+1)
P1.4
Divider
(/1, /2, /4, /8)
+
-
8-bit Up
Counter
PWMRUN
PWM0L
Register
overflow
+
-
Fcpu
Timer 0 overflow
PCLK.1~0
0
1
0
1
PWM1OE
overflow
CLRPWM
Timer 1 overflow
Reserved
00
01
10
11
FP.1~0
PWM0
(P1.4)
P1.5
PWM0OE
PWM1
(P1.5)
PWM1L
Register PWM1L
Buffer
PWM0L
Buffer >
>
Vdd
Vdd
A compare value of all zeroes, 00H, causes the output to remain permanently high. A compare value of
all ones, FFH, results in the PWM output remaining permanently low.
The overall functioning of the PWM module is controlled by the contents of the PWMCON1 and
PWMCON3 registers. The operation of most of the control bits are straightforward. The transfer
Compare registers to the buffer registers is controlled by 8-bit counter overflow, while PWMCON1.7
(PWMRUN) allows the PWM to be either in the run or idle state. It has a CLRPWM bit to clear 8-bt up
counter.
When the PWMRUN is cleared, the PWM outputs take on the state they had just prior to the bit being
cleared. In general this state is not known. In order to place the outputs in a known state when
PWMRUN is cleared the Compare registers can be written to either the “all 1” or “all 0” so the output
will have the output desired when the counter is halted.
Note:
During PWM initial run, user is recommended to configure proper PWMn and/or PWM output pin (default high) follow by setting
PWMRUN and CLRPWM bits, prior to enable PWMnOE. This is to avoid unexpected PWM output.
n UVOTO n E
Preliminary N79E352/N79E352R Data Sheet
Publication Release Date: Jul, 29, 2009
- 111 - Revision A06
22. I/O PORT
N79E352(R) has four 8 bits I/O ports; port 0, port 1, port 2, port 3, one partial port 4; P4.0 to P4.3 and
one partial port 5; P5.0 to P5.1. All pins of I/O ports (except port4) can be configured to one of four
types by software. User may configure the mode type for the above port pin by programming PxMy
SFRs.
Port 4 support only quasi mode.
PXM1.Y PXM2.Y[Note] PORT INPUT/OUTPUT MODE
0 0 Quasi-bidirectional.
0 1 Push-Pull
1 0
Input Only (High Impedance)
PORTS.PxS=0, TTL input
PORTS.PxS=1, Schmitt input
1 1 Open Drain
Table 22-1: I/O port configuration table
Note: X = 0-3 and 5. Y = 0-7.
In addition, port default mode is also configurable through CONFIG0.PMODE bit. When PMODE = 1,
ports 1~3 and 5 will default to quasi mode upon all reset. If PMODE = 0, ports 1~3 and 5 will default to
open drain mode upon all reset. See table below.
PORTS CONFIG0.PMODE UPON RESET PXM1,2 RESET VALUE
P0 X Open Drain P0M1,2 = 1111 1111b
P1~3 1 Quasi P(1~3)M1,2 = 0000 0000b
0 Open Drain P(1~3)M1,2 = 1111 1111b
P4 X Quasi Not available.
P5[1]
1 Quasi P5M1 = xxxx x000b
P5M2 = xxxx xx00b
0 Open Drain P5M1 = xxxx x011b
P5M2 = xxxx xx11b
Table 22-2: Default port mode configuration by CONFIG0.PMODE bit.
Note: 1. Product configured to run internal rc.
All port pins can be determined to high or low after reset by configure PRHI bit in the CONFIG0
register.
Besides P4 is permenant Schmitt trigger intput, each I/O port of N79E352(R) may be selected to use
TTL level inputs or Schmitt inputs by P(n)S bit on PORTS SFR register; where n is 0, 1, 2, 3 or 5.
When P(n)S is set to 1, Ports are selected Schmitt trigger inputs on Port(n).
22.1 Quasi-Bidirectional Output Configuration
n UVOTO n E C;H{ % Er
Preliminary N79E352/N79E352R Data Sheet
- 112 -
The default port output configuration for standard N79E352(R) I/O ports is the quasi-bidirectional
output that is common on the 80C51 and most of its derivatives. This output type can be used as both
an input and output without the need to reconfigure the port. This is possible because when the port
outputs a logic high, it is weakly driven, allowing an external device to pull the pin low. When the pin is
pulled low, it is driven strongly and able to sink a fairly large current. These features are somewhat
similar to an open drain output except that there are three pull-up transistors in the quasi-bidirectional
output that serve different purposes. One of these pull-ups, called the “very weak” pull-up, is turned on
whenever the port latch for the pin contains a logic 1. The very weak pull-up sources a very small
current that will pull the pin high if it is left floating.
A second pull-up, called the “weak” pull-up, is turned on when the port latch for the pin contains a logic
1 and the pin itself is also at a logic 1 level. This pull-up provides the primary source current for a
quasi-bidirectional pin that is outputting a 1. If a pin that has a logic 1 on it is pulled low by an external
device, the weak pull-up turns off, and only the very weak pull-up remains on. In order to pull the pin
low under these conditions, the external device has to sink enough current to overpower the weak pull-
up and take the voltage on the port pin below its input threshold.
The third pull-up is referred to as the “strong” pull-up. This pull-up is used to speed up low-to-high
transitions on a quasi-bidirectional port pin when the port latch changes from a logic 0 to a logic 1.
When this occurs, the strong pull-up turns on for a brief time, two CPU clocks, in order to pull the port
pin high quickly. Then it turns off again. The quasi-bidirectional port configuration is shown as below.
Port Pin
2 CPU
Clock Delay
Input Data
Port Latch
Data
P P P
N
VDD
Strong Very
Weak Weak
Figure 22-1: Quasi-Bidirectional Output
22.2 Open Drain Output Configuration
The open drain output configuration turns off all pull-ups and only drives the pull-down transistor of the
port driver when the port latch contains a logic 0. To be used as a logic output, a port configured in this
manner must have an external pull-up, typically a resistor tied to VDD. The pull-down for this mode is
the same as for the quasi-bidirectional mode. The open drain port configuration is shown as below.
n UVOTO n 7/~—{
Preliminary N79E352/N79E352R Data Sheet
Publication Release Date: Jul, 29, 2009
- 113 - Revision A06
Port Pin
Port Latch
Data
N
Input Data
Figure 22-2: Open Drain Output
22.3 Push-Pull Output Configuration
The push-pull output configuration has the same pull-down structure as both the open drain and the
quasi-bidirectional output modes, but provides a continuous strong pull-up when the port latch contains
a logic 1. The push-pull mode may be used when more source current is needed from a port output.
The push-pull port configuration is shown below.
The value of port pins at reset is determined by the PRHI bit in the CONFIG0 register. Ports may be
configured to reset high or low as needed for the application. When port pins are driven high at reset,
they are in quasi-bidirectional mode and therefore do not source large amounts of current. Every
output on the device may potentially be used as a 20mA sink LED drive output. However, there is a
maximum total output current for all ports which must not be exceeded.
All ports pins of the device have slew rate controlled outputs. This is to limit noise generated by quickly
switching output signals. The slew rate is factory set to approximately 10 ns rise and fall times.
Port Pin
Input Data
Port Latch
Data
P
N
VDD
Figure 22-3: Push-Pull Output
22.4 Input Only Mode
The input only port configuation is show in figure 21-4, it is a schmitt-triggered input or TTL input.
n UVOTO n E 4&4”, 4:1
Preliminary N79E352/N79E352R Data Sheet
- 114 -
Port Pin
Input Data
Schmitt-triggered or TTL
Figure 22-4: Push-Pull Output
n UVOTO n
Preliminary N79E352/N79E352R Data Sheet
Publication Release Date: Jul, 29, 2009
- 115 - Revision A06
23. OSCILLATOR
N79E352(R) provides three oscillator input option. These are configured at CONFIG register
(CONFIG0) that include On-Chip RC Oscillator Option, External Clock Input Option and Crystal
Oscillator Input Option. The Crystal Oscillator Input frequency may be supported from 4MHz to 24MHz,
and without capacitor or resister.
Fcpu
Oscillating
Circuit
XTAL1
XTAL2
External
XTAL
1/2
1
0
FS1
(CONFIG1.5)
Internal
Oscillator
(~20kHz)
BOD
WDT
For BOD in
power-saving
mode
PWM, I2C
Fosc
F
RC22M
Timers, UART
00
Ext Clock
10
11
F
OSC1
F
OSC0
CPU Clock
Rate select
ISP
Internal
Oscillator
(22.1184MHz)
F
RC11M
CD0 CD1
PMR[1:0]
Figure 23-1: Oscillator
23.1 On-Chip RC Oscillator Option
The On-Chip RC Oscillator is fixed at 11.0592MHz or 22.1184MHz (selectable by FS1 config bit) ±2%
for N79E352R, ±25% for N79E352 frequency to support clock source. When FOSC1, FOSC0 = 01b, the
On-Chip RC Oscillator is enabled.
23.2 External Clock Input Option
The clock source pin (XTAL1) is from External Clock Input by FOSC1, FOSC0 = 11b, and frequency
range is ffrom 0Hz up to 24MHz.
The device supports a clock output function when either the on-chip RC oscillator or external clock
input options are selected. This allows external devices to synchronize to the device. When enabled,
via the ENCLK bit in the P5M1 register, the clock output appears on the XTAL2/CLKOUT pin whenever
the on-chip oscillator is running, including in Idle Mode. The frequency of the clock output is 1/4 of the
CPU clock rate. If the clock output is not needed in Idle Mode, it may be turned off prior to entering
n UVOTO n E
Preliminary N79E352/N79E352R Data Sheet
- 116 -
Idle, saving additional power. The clock output may also be enabled when the external clock input
option is selected.
23.3 CPU Clock Rate select
The CPU clock of N79E352(R) may be selected by the PMR.CD0/1 bits. If (CD1,CD0) = 01b, the CPU
clock is running at 4 CPU clock per machine cycle, and without any division from source clock (Fosc).
This frequency division function affect all peripheral timings as they are all sourcing from the CPU
clock(Fcpu). The following table shows the PMR.CD1/0 bits definition.
CD1, CD0 Clocks/machine Cycle
0 x 4
1 0 64
1 1 1024
CD0/1 definitions
n UVOTO n = Brownout Voltage Selection
Preliminary N79E352/N79E352R Data Sheet
Publication Release Date: Jul, 29, 2009
- 117 - Revision A06
24. POWER MONITORING
In order to prevent incorrect operation during power up and power drop, the N79E352(R) provides two
power monitor function that are Power-On Detect and Brownout Detect.
24.1 Power On Detect
The PowerOn Detect function is a design to detect power up after power voltage reaches to a level
where Brownout Detect can work. After power on detect, the POR (WDCON.6) will be set to “1” to
indicate an initial power up condition. The POR flag will be cleared by software.
24.2 Brownout Detect and Reset
The N79E352(R) has an on-chip Brown-out Detection circuit for monitoring the VDD level during
operation by comparing it to a programmable brownout trigger level. There are 4 brownout trigger
levels available for wider voltage applications. The 3 nominal levels are 2.6V, 3.8V and 4.5V
(programmable through BOV.1-0 bits). When VDD drops to the selected brownout trigger level (VBOR),
the brownout detection logics will either reset the CPU until the VDD voltage raises above VBOR or
requests a brownout interrupt at the moment that VDD falls and raises through VBOR. The brownout
detection circuits also provides a low power brownout detection mode for power saving. When
LPBOV=1, the brownout detection repeatly senses the voltage for 64/fBRC then turn off detector for
960/fBRC (fBRC = internal rc frequency), if VDD voltage still below brownout trigger level. fBRC, the
frequency of built-in RC oscillator is approximately 20KHz+/-100%.
The Brownout Detect block is shown in Figure 24-1.
BOV1 BOV0 Brownout Voltage
0
x
Brownout voltage is 2.6V
1
0
Brownout voltage is 3.8V
1
1
Brownout voltage is 4.5V
Brownout Voltage Selection
Brownout
Detect
Circuit
0
1
BOF
To Reset
To Brownout interrupt
BOV[1:0]
BOD
LPBOV
BOI
BOS
Figure 24-1: Brown-out Detect Block
n UVOTO n =
Preliminary N79E352/N79E352R Data Sheet
- 118 -
VBOR+
VBOR -
VDD
BOI=0 to select
Brown-out Reset
Set by Hardware
Clear by Software
BOI=1 to select
Brown-out Interrupt
Clear by Software
TBOR :Brown-out Reset Delay Time with about 8mS
Nominal Brown-
out Voltage
Brown-out Status
BOS
TBOR
8ms
Reset
BOF
Figure 24-2: Brown-out Voltage Detection
n UVOTO n =
Preliminary N79E352/N79E352R Data Sheet
Publication Release Date: Jul, 29, 2009
- 119 - Revision A06
25. ICP(IN-CIRCUIT PROGRAM) FLASH PROGRAM
The ICP(In-Circuit-Program) mode is another approach to access the Flash EPROM. There are only 3
pins needed to perform the ICP function. One is mode input, shared with RST pin, which must be kept
in Vdd voltage in the entire ICP working period. One is clock input, shared with P1.7, which accepts
serial clock from external device. Another is data I/O pin, shared with P1.6, that an external ICP
program tool shifts in/out data via P1.6 synchronized with clock(P1.7) to access the Flash EPROM of
N79E352(R).
(Note, While PRHI=0, P1.6, P1.7 are still quasi high during reset period. During reset period , P1.6,
P1.7 cannt switch to open-drain by setting config).
N79E352(R)
RST
P1.6
P1.7
Vdd
Vss
To I/O pin
To I/O pin
To Reset or Input Pin
Vdd
Vpp
Data
Clock
Vss
ICP Program Tool
Vcc
JumperICP Connector
System Board
ICP Power
Jumper
Figure 26-1: ICP Writer Tool connector pin assign
Note:
1. When using ICP to upgrade code, the RST, P1.6 and P1.7 must be taken within design system
board.
2. After program finished by ICP, to suggest system power must power off and remove ICP
connector then power on.
3. It is recommended that user performs erase function and programming configure bits
continuously without any interruption.
4. During ICP mode, all PWM pins will be tri-stated.
n UVOTO n E
Preliminary N79E352/N79E352R Data Sheet
- 120 -
26. CONFIG BITS
The N79E352(R) has two CONFIG bits (CONFIG0 located at FB00h, CONFIG1 located at FB01h) that
must be defined at power up and can not be set the program after start of execution. Those features
are configured through the use of two flash EPROM bytes, and the flash EPROM can be programmed
and verified repeatedly. Until the code inside the Flash EPROM is confirmed OK, the code can be
protected. The protection of flash EPROM (CONFIG1) and those operations on it are described below.
26.1 CONFIG0
WDTCK PMODE PRHI BPFR Fosc 1 Fosc 0
7 6 5 4 3 2 1 0
WDTCK : Watchdog Timer Clock Selection Bit.
PRHI : Port Reset High Bit.
CBOD : Config Brownout Detect Enable Bit.
Fosc1 : CPU Oscillator Type Select Bit 1.
Fosc0 : CPU Oscillator Type Select Bit 0.
BPFR : Bypass Clock Filter Bit.
PMODE : Port MODE Bit.
CBOD
-
Figure 25-1: Config0 register bits
BIT NAME FUNCTION
7 WDTCK
Clock source of Watchdog Timer select bit:
0: The internal 20KHz RC oscillator clock is for Watchdog Timer clock used.
1: The uC clock is for Watchdog Timer clock used.
6 PMODE
Port Mode Type select bit:
0: Port 1~3 and 5 reset to open drain mode.
1: Port 1~3 and 5 reset to quasi mode.
5 PRHI
Port Reset High or Low select bit:
0: Port reset to low state.
1: Port reset to high state.
Note: For product to run external program (/EA=0), user need to ensure PRHI is set to 1.
4 - Reserved.
3 CBOD
Config Brownout Detect Enable bit
0: Disable Brownout Detect.
1: Enable Brownout Detect.
2 BPFR
Bypass Clock Filter.
0: Disable Clock Filter.
1: Enable Clock Filter.
1 Fosc1 CPU Oscillator Type select bit 1.
n UVOTO n =
Preliminary N79E352/N79E352R Data Sheet
Publication Release Date: Jul, 29, 2009
- 121 - Revision A06
0 Fosc0 CPU Oscillator Type select bit 0.
Oscillator Configuration bits:
Fosc1
Fosc0
OSC source
0
0
4MHz ~ 24MHz crystal
0
1
Internal RC Oscillator (FS1 bit in CONFIG1.5 will determine
either 11.0592MHz or 22.1184MHZ)
1
0
Reserved
1
1
External Oscillator in XTAL1; XALT2 is in Tri-state
26.2 CONFIG1
7 6 5 4 3 2 1 0
C6C7 FS1
C7 : 8/4K Flash EPROM Code Lock Bit
C6 : 512/256/128/64 byte Data Lock Bit
FS1 : Internal RC 11.0592MHz/22.1184MHz Selection Bit
C1 -
CBOV.1-0
CBOV.1-0 : Brownout Level Selection Bits
C1 : Movc Inhibit Enable Bit
-
Figure 25-2: Config1 register bits
C7: 8K Flash EPROM Lock bit
This bit is used to protect the customer’s program code. It may be set after the programmer finishes
the programming and verifies sequence. Once this bit is set to logic 0, both the Flash EPROM data and
CONFIG Registers can not be accessed again.
C6: 128 byte Data Flash EPROM Lock bit
This bit is used to protect the customer’s 128 bytes of data code. It may be set after the programmer
finishes the programming and verifies sequence. Once this bit is set to logic 0, both the 128 bytes of
Flash EPROM data and CONFIG Registers can not be accessed again.
Bit 7 Bit 6 Function Description
1 1 Both security of 8KB program code and 128 Bytes data area are not locked. They can
be erased, programmed or read by Writer or JTAG mode.
0 1 The 8KB program code area is locked. It can not be read and written by Writer or
JTAG mode. The 128 Bytes data area can be program or read. The bank erase is
invalid.
1 0 Not supported.
0 0 Both security of 8KB program code and 128 Bytes data area are locked. They can not
be read and written by Writer or JTAG mode.
FS1: Internal Oscillator selection bit
This bit is used to select internal oscillator.
n UVOTO n =
Preliminary N79E352/N79E352R Data Sheet
- 122 -
FS1 Internal Oscillator Output
0
11.0592MHz
1 22.1184MHz (default)
Internal Oscillator Selection Table
CBOV.1-0: Brownout level selection bits
These bits are used to select brownout voltage level.
CBOV.1 CBOV.0 Brownout Voltage
1 x Brownout voltage is 2.6V
0
1
Brownout voltage is 3.8V
0
0
Brownout voltage is 4.5V
C1: MOVC inhibit enable bit
MOVC inhibit
enable bit MOVC access
0
The MOVC instruction in external
memory cannot access the code in
internal memory.
1
No restriction.
This bit is used to restrict the accessible region of the MOVC instruction. It can prevent the MOVC
instruction in external program memory from reading the internal program code. When this bit is set to
logic 0, a MOVC instruction in external program memory space will be able to access code only in the
external memory, not in the internal memory. A MOVC instruction in internal program memory space
will always be able to access the ROM data in both internal and external memory. If this bit is logic 1,
there are no restrictions on the MOVC instruction.
n UVOTO n =
Preliminary N79E352/N79E352R Data Sheet
Publication Release Date: Jul, 29, 2009
- 123 - Revision A06
27. ELECTRICAL CHARACTERISTICS
27.1 Absolute Maximum Ratings
SYMBOL PARAMETER CONDITION RATING UNIT
DC Power Supply VDDVSS -0.3 +7.0 V
Input Voltage VIN VSS-0.3 VDD+0.3 V
Operating Temperature TA -40 +85 °C
Storage Temperature Tst -55 +150 °C
Sink current ISK 90 mA
Note: Exposure to conditions beyond those listed under absolute maximum ratings may adversely affects the lift and reliability
of the device.
n UVOTO n = TA = -4U~85°C unless otherwise specwfied.
Preliminary N79E352/N79E352R Data Sheet
- 124 -
27.2 D.C. Characteristics
(TA = -40~85°C, unless otherwise specified.)
PARAMETER SYM. SPECIFICATION TEST CONDITIONS
MIN. TYP. MAX. UNIT
Operating Voltage VDD 2.4 5.5 V VDD=4.5V ~ 5.5V @ 24MHz
VDD=2.7V ~ 5.5V @ 12MHz
VDD=2.4V ~ 5.5V @ 4MHz
Operating Current IDD1 5 mA No load, RST = VDD, VDD= 3.0V
@ 11.0592MHz
IDD2 15 mA No load, RST = VDD, VDD= 5.0V
@ 22.1184MHz
Idle Current IIDLE 4 mA No load, VDD = 3.0V
@ 11.0592MHz
Power Down Current IPWDN 1 5 µA No load, VDD = 5.5V
@ Disable BOV function
1 5 uA No load, VDD = 3.0V
@ Disable BOV function
Input / Output
Input Current P0, P1, P2, P3, P4,
P5 IIN1 -50 - +10 µA VDD = 5.5V, VIN = 0V or VIN=VDD
Input Current P1.5(RST pin)[1] IIN2 -48 -32 -24 µA VDD = 5.5V, VIN = 0.45V
Input Leakage Current P0, P1,
P2, P3, P5 (Open Drain) ILK -10 - +10 µA VDD = 5.5V, 0<VIN<VDD
Logic 1 to 0 Transition Current
P0, P1, P2, P3, P4, P5
ITL
[*3]
-450 - -246 µA VDD = 5.5V, VIN<2.0V
-93 - -56 VDD=2.4 Vin = 1.3v
Input Low Voltage P0, P1, P2,
P3, P4, P5 (TTL input) VIL1
0 - 1.0
V
VDD = 4.5V
0 - 0.6
1.0 VDD = 2.4V
Input High Voltage P0, P1, P2,
P3, P4, P5 (TTL input) VIH1 2.0 - VDD +0.2 V VDD = 5.5V
1.5 - VDD +0.2 VDD = 2.4V
Input Low Voltage XTAL1[*2] VIL3 0 - 0.8 V VDD = 4.5V
0 - 0.4 VDD = 3.0V
Input High Voltage XTAL1[*2] VIH3 3.5 - VDD +0.2 V VDD = 5.5V
2.4 - VDD +0.2 VDD = 3.0V
Negative going threshold
(Schmitt input) VILS -0.5 - 0.3VDD V
Positive going threshold
(Schmitt input) VIHS 0.7VDD - VDD+0.5 V
Hysteresis voltage VHY 0.2VDD V
Input Low Voltage RST [*1] V IL21 - 1.0 1.6 V VDD=4.5V
n UVOTO n =
Preliminary N79E352/N79E352R Data Sheet
Publication Release Date: Jul, 29, 2009
- 125 - Revision A06
V IL22 - 0.7 0.8 V VDD=2.7V
Input High Voltage RST [*1] VIH21 3.5 2.3 VDD+0.2 V VDD=5.5V
VIH22 2 1.5 VDD+0.2 V VDD=2.7V
Source Current P0, P1, P2, P3,
P5
(PUSH-PULL Mode)
ISR1 -16 -26 -36 mA VDD = 4.5V, VS = 2.4V
-5 -7.9 -11 mA VDD = 2.4V, VS = 2.0V
Source Current P0, P1, P2, P3,
P4, P5
(Quasi-bidirectional Mode)
ISR2 -150 -210 -360 µA VDD = 4.5V, VS = 2.4V
-39 -53 -69 µA VDD = 2.4V, VS = 2.0V
Sink Current P0, P1, P2, P3, P4,
P5
(Quasi-bidirectional and PUSH-
PULL Mode)
ISK2
13 18.5 24 mA VDD = 4.5V, VS = 0.45V
9 15 21 VDD = 2.4V, VS = 0.45V
Brownout voltage with BOV[1:0]
=0xb VBO2.4 2.55 2.6 2.85 V
Brownout voltage with BOV[1:0]
=10b VBO3.8 3.65 3.8 3.95 V
Brownout voltage with BOV[1:0]
=11b VBO4.5 4.35 4.5 4.65 V
Hysterisis range of BOD voltage VBh
35 - 150 mV VDD = 2.4V~5.5V,
(LPBOD,BOI) = (0,x) or (1,0)
10 - 60 mV VDD = 2.4V~5.5V,
(LPBOD,BOI)=(1,1)
Sink current [*2]
P0, P2, ALE,
/PSEN
Isk31
-16 -26 -36
mA
VDD=4.5V, Vs = 0.45V
Isk32
-5 -7.9 -11
mA
VDD=2.7V, Vs = 0.45V
Source current [*2] P0, P2, ALE,
/PSEN
Isr31 13 18.5 24 mA VDD=4.5V, Vs = 2.4V
Isr32 9 15 21 mA VDD=2.7V, Vs = 2.0V
Notes: *1. RST pin is a Schmitt trigger input. RST has internal pull-low resistor.
*2. XTAL1 is a CMOS input.
*3. Pins of P0, P1, P2, P3 and P5 can source a transition current when they are being externally driven from 1 to 0.
The transition current reaches its maximum value when Vin approximates to 2V.
27.3 A.C. Characteristics
t
CLCL
t
CLCX
t
CHCX
t
CLCH
t
CHCL
Note: Duty cycle is 50%.
n UVOTO n =
Preliminary N79E352/N79E352R Data Sheet
- 126 -
27.3.1 External Clock Characteristics
PARAMETER SYMBOL MIN. TYP. MAX. UNITS NOTES
Clock High Time tCHCX 22.6 - - nS
Clock Low Time tCLCX 22.6 - - nS
Clock Rise Time tCLCH - - 10 nS
Clock Fall Time tCHCL - - 10 nS
27.3.2 AC Specification
PARAMETER SYMBOL VARIABLE CLOCK MIN. VARIABLE CLOCK MAX. UNITS
Oscillator Frequency 1/tCLCL 0 24 MHz
27.3.3 External clock Characteristics
PARAMETER SYMBOL MIN TYP MAX UNITS NOTES
Clock High Time tCHCX 12.5 ns
Clock Low Time tCLCX 12.5 ns
Clock Rise Time tCLCH 10 ns
Clock Fall Time tCLCL 10 ns
tCLCL
tCLCX
tCHCX
tCLCH
tCHCL
Note: Duty cycle is 50%
Figure 26-1 External clock characteristics
27.3.4 Serial Port Mode 0 Timing Characteristics
PARAMETER SYMBOL MIN TYP MAX UNITS NOTES
Serial Port Clock Cycle Time
SM2=0 12 clocks per cycle
SM2=1 4 clocks per cycle
tXLXL
12 tCLCL
4 tCLCL
ns
Output Data Setup to Clock Rising Edge
SM2=0 12 clocks per cycle
SM2=1 4 clocks per cycle
tQVXH
10 tCLCL
3 tCLCL
ns
n UVOTO n =
Preliminary N79E352/N79E352R Data Sheet
Publication Release Date: Jul, 29, 2009
- 127 - Revision A06
Output Data Hold to Clock Rising Edge
SM2=0 12 clocks per cycle
SM2=1 4 clocks per cycle
tXHQX
2 tCLCL
tCLCL
ns
Input Data Hold after Clock Rising
SM2=0 12 clocks per cycle
SM2=1 4 clocks per cycle
tXHDX
tCLCL
tCLCL
ns
Clock Rising Edge to Input Data Valid
SM2=0 12 clocks per cycle
SM2=1 4 clocks per cycle
tXHDV
11 tCLCL
3 tCLCL
ns
27.3.5 Program Memory Read Cycle
tLLAX1
tPXIZ
tPLAZ
tLLPL
tPXIX
tPLIV
tAVIV2
tAVIV1
tPLPH
tAVLL
ADDRESS A8-15ADDRESS A8-15
ADDRESS
A0-A7
INSTRUCTION
IN
ADDRESS
A0-A7
PORT2
PORT0
PSEN
ALE
tLLIV
tLHLL
Figure 26-2 Program Memory Read Cycle
n UVOTO n
Preliminary N79E352/N79E352R Data Sheet
- 128 -
27.3.6 Data Memory Read Cycle
tAVLL
tAVWL1
tLLAX1
tWHLH
tRLDV
tRLRH
tRLAZ tRHDZ
tRHDX
tAVDV2
tAVDV1
tLLWL
ADDRESS
A0-A7
INSTRUCTION
IN DATA
IN
ADDRESS
A0-A7
tLLDV
PORT2
PORT0
PSEN
ALE
RD
ADDRESS A8-15
Figure 26-3 Data Memory Read Cycle
27.3.7 Data Memory Write Cycle
tAVLL
tAVWL1
tLLAX2
tWHLH
tWLWH
tQVWX tWHQX
tAVDV2
tLLWL
INSTRUCTION
IN DATA OUT
ADDRESS
A0-A7
ADDRESS
A0-A7
PORT2
PORT0
PSEN
ALE
WR
ADDRESS A8-15
Figure 26-4 Data Memory Write Cycle
n U VOTO n '=
Preliminary N79E352/N79E352R Data Sheet
Publication Release Date: Jul, 29, 2009
- 129 - Revision A06
27.3.8 I2C Bus Timing Characteristics
PARAMETER SYMBOL Standard Mode I2C Bus UNIT
Min. Max.
SCL clock frequency fSCL 0 100 kHz
bus free time between a STOP and START
condition tBUF 4.7 - uS
Hold time (repeated) START condition. After this
period, the first clock pulse is generated tHd;STA 4.0 - uS
Low period of the SCL clock tLOW 4.7 - uS
HIGH period of the SCL clock tHIGH 4.0 - uS
Set-up time for a repeated START condition tSU;STA 4.7 - uS
Data hold time tHD;DAT 5.0 - uS
Data set-up time tSU;DAT 250 - nS
Rise time of both SDA and SCL signals tr - 1000 nS
Fall time of both SDA and SCL signals tf - 300 nS
Set-up time for STOP condition tSU;STO 4.0 - uS
Capacitive load for each bus line Cb - 400 pF
t
BUF
STOP
SDA
SCL
START
t
HD;STA
t
LOW
t
HD;DAT
t
HIGH
t
f
t
SU;DAT
Repeated
START
t
SU;STA
t
SU;STO
STOP
t
r
Figure 26-5: I2C Bus Timing
EXPLANATION OF LOGIC SYMBOLS
In order to maintain compatibility with the original 8051 family, this device specifies the same
parameter as such device, using the same symbols. The explanation of the symbols is as follows.
t Time A Address
C Clock D Input Data
H Logic level high L Logic level low
I Instruction P
PSEN
Q Output Data R
RD
signal
V Valid W
WR
signal
X No longer a valid state Z Tri-state
n UVOTO n E
Preliminary N79E352/N79E352R Data Sheet
- 130 -
27.4 RC OSC AND AC CHARACTERISTICS
(VDDVSS = 2.4~5V, TA = -40~85°C.)
Parameter Specification (reference) Test Conditions
Min. Typ. Max. Unit
Frequency accuracy
of On-chip RC
oscillator
(for N79E352)
-25 25 % VDD=2.4V~5.5V, TA = -40°C ~85°C
Frequency accuracy
of On-chip RC
oscillator with
calibration1
(for N79E352R)
-2
2
%
VDD=4.5V~5.5V, TA = 25°C
-5
5
%
VDD=2.7V~5.5V, TA = 0~85°C
-7
7
%
VDD=2.7V~5.5V, TA = -20~85°C
-9
9
%
VDD=2.7V~5.5V, TA = -40~85°C
Wakeup time
256
clk
Note:
1. These values are for design guidance only and are not tested.
27.5 Typical Application Circuit
CRYSTAL C1 C2 R
4MHz ~ 24MHz without without without
The above table shows the reference values for crystal applications.
XTAL2
XTAL1
C1
C2
R
N79E352(R)
n UVOTO n _ fififififififififififififififlfifififlfi O O O UUHHHHHHHHHHHHHHUHHHHUHHUUHHHHHHHH
Preliminary N79E352/N79E352R Data Sheet
Publication Release Date: Jul, 29, 2009
- 131 - Revision A06
28. PACKAGE DIMENSIONS
28.1 40-pin DIP
1.37
1.22
0.054
0.048
Symbol
Min
Nom
Max
Max
Nom
Min
Dimension in inch
Dimension in mm
A
B
c
D
e
A
L
S
A
A
1
2
E
0.050
1.27
0.210
5.33
0.010
0.150
0.016
0.155
0.018
0.160
0.022
3.81
0.41
0.25
3.94
0.46
4.06
0.56
0.008
0.120
0.670
0.010
0.130
0.014
0.140
0.20
3.05
0.25
3.30
0.36
3.56
0.540
0.550
0.545
13.72
13.97
13.84
17.02
15.24
14.99
15.49
0.600
0.590
0.610
2.29
2.54
2.79
0.090
0.100
0.110
B
1
1
e
E
1
2.055
2.070
52.20
52.58
0
15
0.090
2.29
0.650
0.630
16.00
16.51
15
0
Seating Plane
e
A
2
A
c
E
Base Plane
1
A
1
e
L
A
S
1
E
D
1
B
B
40
21
20
1
α
α
n UVOTO n 33333333333 r—H—H—H—H—H—H—H—H—H—‘m x_u_u_u_u_u_u_u_u_u_u_1 [[[EEEEEEEE 3mm J1
Preliminary N79E352/N79E352R Data Sheet
- 132 -
28.2 44-pin PLCC
44
40
39
29
28
18
17
7
6
1
L
c
1
b
2
A
H
D
D
e
b
E
H
E
y
A
A
1
Seating Plane
D
G
G
E
Symbol
Min
Nom
Max
Max
Nom
Min
Dimension in inch
Dimension in mm
A
b
c
D
e
H
E
L
y
A
A
1
2
E
b
1
H
D
G
G
D
E
0.020
0.145
0.026
0.016
0.008
0.648
0.590
0.680
0.090
0.150
0.028
0.018
0.010
0.653
0.610
0.690
0.100
0.050
BSC
0.185
0.155
0.032
0.022
0.014
0.658
0.630
0.700
0.110
0.004
0.51
3.68
0.66
0.41
0.20
16.46
14.99
17.27
2.29
3.81
0.71
0.46
0.25
16.59
15.49
17.53
2.54
1.27
4.70
3.94
0.81
0.56
0.36
16.71
16.00
17.78
2.79
0.10
BSC
16.71
16.59
16.46
0.658
0.653
0.648
16.00
15.49
14.99
0.630
0.610
0.590
17.78
17.53
17.27
0.700
0.690
0.680
n UVOTO n
Preliminary N79E352/N79E352R Data Sheet
Publication Release Date: Jul, 29, 2009
- 133 - Revision A06
28.3 44-pin PQFP
0.25
0.10
0.010
0.004
Symbol
Min
Nom
Max
Max
Nom
Min
Dimension in inch
Dimension in mm
A
b
c
D
e
H
D
H
E
L
y
0
A
A
L
1
1
2
E
0.006
0.15
-
-
0.002
0.075
0.01
0.081
0.014
0.087
0.018
1.90
0.25
0.05
2.05
0.35
2.20
0.45
0.390
0.510
0.025
0.063
0.004
0
10
0.394
0.520
0.031
0.398
0.530
0.037
9.9
0.80
12.95
0.65
1.60
10.00
13.20
0.8
10.1
13.45
0.95
0.398
0.394
0.390
0.530
0.520
0.510
13.45
13.20
12.95
10.1
10.00
9.9
10
0
0.10
.0315
0.01
0.02
0.25
0.5
Seating Plane
11
22
12
See Detail F
e
b
A
y
1
A
A
2
L
L
1
c
E
E
H
1
D
44
H
D
34
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Preliminary N79E352/N79E352R Data Sheet
- 134 -
28.4 48-pin LQFP
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Preliminary N79E352/N79E352R Data Sheet
Publication Release Date: Jul, 29, 2009
- 135 - Revision A06
29. REVISION HISTORY
VERSION DATE PAGE DESCRIPTION
A01 Aug, 14, 2008 - Initial Issued
A02 Aug, 21, 2008 7,8 Update pin configurations.
A03 Feb, 2, 2009 - Add access external memory diagram
A04 Feb, 9, 2009
- Modify the part no. with each package
1. 40DIP: N79E352ADG, N79E352RADG
2. 44PLCC: N79E352APG, N79E352RAPG
3. 44PQFP: N79E352AFG, N79E352RAFG
4. 48LQFP: N79E352ALG, N79E352RALG
A05 Apr, 22, 2009
-
108~109
124~125
115
1. Correct typo errors.
2. Release input capture 0 function in Section 20.
3. Re-arrange section sequency after Section 20.
2. Update D.C specification.
3. Renew Figure 0-1: Oscillator
A06 Jul, 29, 2009 119 1. Add ICP description.
Important Notice
Nuvoton Products are neither intended nor warranted for usage in systems or equipment, any
malfunction or failure of which may cause loss of human life, bodily injury or severe property
damage. Such applications are deemed, “Insecure Usage”.
Insecure usage includes, but is not limited to: equipment for surgical implementation, atomic
energy control instruments, airplane or spaceship instruments, the control or operation of
dynamic, brake or safety systems designed for vehicular use, traffic signal instruments, all
types of safety devices, and other applications intended to support or sustain life.
All Insecure Usage shall be made at customer’s risk, and in the event that third parties lay
claims to Nuvoton as a result of customer’s Insecure Usage, customer shall indemnify the
damages and liabilities thus incurred by Nuvoton.

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