Make connections to the PIXI ports as follows: Port 4 (P4) is a DAC generating a sawtooth, which is connected into level-translator Port 14 (P14) using an external potentiometer. Connect the output of the DAC to one end of the pot’ and the other end of the pot’ to GROUND which is the middle row of pins. Connect the wiper of the potentiometer to port 14 (P14) and the output Port 3 (P3) back with an ADC on Port 13 (P13). This shows a potentiometer adjustable pulse-width generator.