Rev 1.4 (Oct 2008) DLP-TXRX DLP Design, Inc.
1
DLP-TXRX-G USB / SERIAL ADAPTER
NOW LEAD-FREE!
VCCIO
VCC
USBDP TX
USBDM RX
RXLED
TXLED
DTR#
FTDI FT232R
USB Type 'B'
Mini connector
to Host PC/
Linux/Mac User uC, uP,
DSP, FPGA
Reset
10K
DLP-TXRX
R
External VCC
IO Voltage Select
Jumper
5V 3.0 - 5.25V
1
3
2
5
4
VCCIO
1.0 Introduction
The DLP-TXRX-G USB-to-serial adapter is designed to easily connect a
microcontroller/DSP/FPGA/etc to a host PC; or upgrade a legacy RS232 device to USB
via a 2-wire serial interface with minimal design effort. Virtual COM Port (VCP) drivers
are provided royalty-free that make the DLP-TXRX-G look like a standard
Windows/Linux/Mac RS232 port to the user’s host program.
User uC, uP,
DSP, FPGA
Level Shifter
The old way...
DB9
USB Type 'B'
Mini connector
to Host PC/
Linux/Mac
DLP-TXRX User uC, uP,
DSP, FPGA
The USB way!
TX
RX
TX
RX
Rev 1.4 (Oct 2008) DLP-TXRX DLP Design, Inc.
2
1.1 Features Summary
• Royalty-free Virtual COM Port drivers
• As few as 2 wire serial interface (RX, TX and ground)
• Standard baud rates from 300 to 921,600 baud
• Support for non-standard baud rates
• One open-collector output (pin 4): can be used for resetting microcontroller under
software control (DTR)
• Input provided (pin 5) for user-selectable interface voltage
• Red and green LEDs to indicate transmit and receive activity
• USB 2.0 interface compatible
• USB Description strings, VID and PID configurable in on-chip EEPROM
• EEPROM Configurable in-circuit via USB
• Support for the RS232 BREAK setting and detection conditions
1.2 General Description
All operational power for the DLP-TXRX-G is taken from the host PC USB port or
upstream hub. All power required by user electronics must be provided by external
power supply.
FTDI provides a royalty free Virtual COM Port (VCP) driver that makes this USB device
appear as a standard COM port to the PC. Most existing software applications should be
able interface with the Virtual COM Port simply by reconfiguring them to use the new
COM ports created by the driver. Using the VCP drivers, an application program would
communicate with the DLP-TXRX-G in exactly the same way as it would a regular
RS232 COM port - using the Windows VCOMM API calls or a COM port library.
Also available is a DLL version of the drivers that allows application programmers to
interface software directly to the device using a Windows DLL. Both the VCP and DLL
version of the drivers are available for download from both the dlpdesign.com and
ftdichip.com web sites.
The on-chip EEPROM can be used to customize the USB VID, PID, Serial Number,
Product Description Strings and Power Descriptor value of the DLP-RXTX-G for OEM
applications. The EEPROM is programmable in-circuit via USB using a utility program
(MPROG) available from both www.ftdichip.com and www.dlpdesign.com.
VIRTUAL COM PORT (VCP) DRIVER SUPPORT FOR:
• Windows 98 / 98 SE / 2000 / ME / XP
• Windows CE
• MAC OS-8 and OS-9
• MAC OS-X
• Linux 2.40 and greater
Rev 1.4 (Oct 2008) DLP-TXRX DLP Design, Inc.
3
1.3 DTR Open Collector Output
Pin 4 of the DLP-TXRX-G is an open-collector output that is controlled by the DTR#
output of the FT232RL. Upon power up of the DLP-TXRX-G (i.e. when connected to
the host PC), pin 4 is initially driven low via an open-collector transistor until the host
application opens the COM port that the DLP-TXRX-G is assigned to. Once the port is
opened, pin 4 becomes high-impedance. From this point forward, the state of pin 4 can
be changed under software control via the user’s application program by setting and
clearing DTR#.
NOTE: if pin 4 is used to reset an external microcontroller, then upon power up the
processor will not run until the COM port is opened by the host application.
1.4 VCCIO Input
Pin 5 is used to provide power to the I/O pins of the FT232RL in instances where the
external microcontroller/DSP/FPGA/etc is operating at a voltage other than 5 volts. The
acceptable input voltage range on Pin 5 is 1.8 to 5.25 volts. If the external processor is
running at 5.0 volts then Pin 5 can be left disconnected.
If the external processor is running at a voltage other than 5 volts then the solder bridge at
location ‘5’ on the DLP-TXRX-G pcb must be removed and a solder bridge at location
‘3’ must be applied in order for the voltage applied to pin 5 to be used.
Rev 1.4 (Oct 2008) DLP-TXRX DLP Design, Inc.
4
1.5 Activity LEDs
Transmit and receive LEDs are provided to indicate activity. When data is being
transmitted or received, the respective LEDs illuminate in order to provide indication of
data transfer. Circuitry in the FT232RL ensures that even a small percentage of data
transfer is visible to the end user.
2.0 Mechanical Dimensions >>> Preliminary < inches="" (mm)="" ‘7="" 0.28="" iyg.="" 1.85="" iyg.="" i="" (47.0="" iyp.)="" —="" l—o="" 0.55="" mg.="" d="" 8="" (14.0="" typ.)="" o="" o="" 2.20="" iyp.="" \="" (55.91yp.)="" .035="" x="" 5="" 0.23="" iyp.="" (6-41)?)="" f="" i="" 1—11—1="" u—u—1="" 1—1="" fl="" rev="" 1.4="" (oct="" 2008)="" 5="" dlp="">Rev 1.4 (Oct 2008) DLP-TXRX DLP Design, Inc.
5
2.0 Mechanical Dimensions >>> Preliminary <<<
Inches (mm)
.035 x 5
(0.9 typ.)
1.85 typ.
(47.0 typ.)
0.55 typ.
(14.0 typ.)
2.20 typ.
(55.9 typ.)
0.28 typ.
(7.1 typ.)
0.23 typ.
(6.4 typ.)
salcs@dlpdcsi2n.com
suggerl®dlgdcsign£om
th://www.dlgdcsign.com
Rev 1.4 (Oct 2008) DLP-TXRX DLP Design, Inc.
6
3.0 Disclaimer
© DLP Design, Inc., 2002 / 2008
Neither the whole nor any part of the information contained in, or the product described
in this manual, may be adapted or reproduced in any material or electronic form without
the prior written consent of the copyright holder.
This product and its documentation are supplied on an as-is basis and no warranty as to
their suitability for any particular purpose is either made or implied. DLP Design, Inc.
will not accept any claim for damages howsoever arising as a result of use or failure of
this product. Your statutory rights are not affected. This product or any variant of it is not
intended for use in any medical appliance, device or system in which the failure of the
product might reasonably be expected to result in personal injury.
This document provides preliminary information that may be subject to change without
notice.
4.0 Contact Information
DLP Design, Inc.
1605 Roma Lane
Allen, TX 75013
Phone: 469-964-8027
Fax: 415-901-4859
E-Mail ( Sales ) : sales@dlpdesign.com
E-Mail ( Support ) : support@dlpdesign.com
Web Site URL : http://www.dlpdesign.com
5
5
4
4
3
3
2
2
1
1
D D
C C
B B
A A
DLP-TXRX-G
5
3
External 1.8 - 5.25V
5.0V from USB Port
(default)
-->
<--
USBVCC
EXTVCIO
EXTVCIO
USBVCC
VCC_IO
VCC_IO
USBVCC
VCCIO
C1
.01
C6 .1
J1
INTERFACE HEADER
1
2
3
4
5
JP3
1
2
3
R6
10K
C3
47pF
R5
100
CN1
Mini-B USB Connector
1
2
3
4
5
C5
.1uF
FB1
240-1018-1
1 2
R4
100
Q1
2N3904
C2
10/10 Tant
RX
GREEN LED
TX
RED LED
U1
FT232R
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
TXD
DTR#
RTS#
VCCIO
RXD
RI#
GND
VCCIN/NC
DSR#
DCD#
CTS#
CBUS4
CBUS2
CBUS3
USBDP
USBDM
3V3OUT
GND
RESET#
VCC5 IN
GND
CBUS1
CBUS0
AVCC/NC
AGND
TEST
OSCI
OSCO
C4
47pF
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