Programming 8-bit PIC Microcontrollers in C

3.9. PIC16 C Analog Output

• Waveform generator test system

• Waveform test program

• Waveform output

In microcontroller applications, analog output is not needed as often as analog input, so no digital to analog converter (DAC) is built into the PIC MCU. An external DAC is needed to generate analog output signals.

A serial DAC may be used to output a precision DC reference voltage or low-frequency analog signal, using SPI or I²C to transfer the data. A 10-bit or 12-bit output is typically provided, giving a precision of about 0.1 or 0.025%, respectively. However, the serial data transfer is inherently slow. In the demo system described here (Figure 3.12), higher speed is possible with parallel output to the DAC. The waveform generator circuit generates ...