Python 3.x module for use with MCP4131 digital potentiometer.

This requires the py-spidev and python-dev modules for the SPI connection. I used an MCP4131 10kOhm digital pot connected to a Raspberry Pi 3 for development of this module.

Connections to the MCP4131 from the Pi are as follows

• Pi MOSI to 560 ohm resistor to MCP SDI/SDO
• Pi MISO to MCP SDI/SDO
• Pi SCLK to MCP SCK
• Pi CE1 to MCP CS
• Pi 3.3V to MCP Vdd
• Pi Gnd to MCP Gnd/Vss

For testing I used a Fluke7 3 Series II multimeter measuring ohms placed across the MCP P0B and MCP P0W terminals

Current functions include:

• set_wiper_value(wiperValue = 0x40, wiper = 0):=
• read_wiper_value(wiper = 0)
• increment_wiper(increment = 1, wiper = 0)
• decrement_wiper(decrement = 1, wiper = 0)
• set_wiper_controls(pA = 1, pW = 1, pB= 1, shutdown = 1, wiper = 0)
• read_wiper_controls()

For information on how the chip works check out the datasheet

Note: For the increment and decrement commands I did not use the 8 bit increment/decrement commands found in the data sheet. They never worked for me, on the Pi or on an Arduino UNO. I used a 2 step version instead where I read the current wiper value first and then increment/decrement that by the specified amount and write that value back to the wiper value register.