MCP4921 Module

This module contains the driver for Microchip MCP4921 single channel 12-bit digital to analog converter with SPI serial interface (datasheet).


from microchip.mcp4921 import mcp4921


mcp = mcp4921.MCP4921(SPI0, D17)

MCP4921 class

class MCP4921(spidrv, cs, clk = 400000)

Creates an instance of the MCP4921 class.

  • spidrv – SPI Bus used ‘(SPI0, ...)’
  • cs – Chip select pin
  • clk – Clock speed, default 400 kHz
set_value(v, gain = 1, buff = False)

Sends the 12-bit value v to the DAC. The gain of the output amplifier can be set through gain parameter, valid values are 1 and 2.

Analog Output Voltage = ( v / 4096) * Vref * gain

If buff is True, the device buffers the Voltage Reference input increasing the input impedance but limiting the input range and frequency response. If buff is False the input range is wider (from 0V to Vdd) and the typical input impedence is 165 kOhm with 7pF. If in Shutdown mode, the device is changed to Active mode. In this case the output settling time increases to 10 us.


Shutdown the device. During Shutdown mode, most of the internal circuits are turned off for power savings and there will be no analog output.