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Project Notes

#264 DigitalPots/MCP42010

Control the MCP42010 dual 10kΩ digital potentiometer with an Arduino and hardware SPI.



I’m trying out some digital potentiometers for an application. This is a test of the MCP42010 - the dual 10kΩ version of the MCP41XXX/MCP42XXX.

This is a pretty nice chip:

  • independant control of the two wipers via standard SPI
  • can be daisy-chained
  • 8-bit resolution for the wiper setting
  • polarity of the A/B pot connections does not matter
  • reset pin (sets wiper to middle position)
  • hardware/software shutdown control

Typical Applications:

  • Programmable gain circuits
  • Programmable differential input amplifier


It is possible to operate the device in SPI_MODE0 and SPI_MODE3

  • SPI_MODE0: Clock Polarity=0, Clock Phase=0
  • SPI_MODE3: Clock Polarity=1, Clock Phase=1

It supports a basic command + data byte structure, per the timing diagram from the datasheet:


Unfortunately it appears the MCP42010 cannot handle two commands in a single SPI transaction, hence if A and B wiper settings are different they need to be sent separately. If A and B wiper settings are the same, they can be sent in one command.

Test Program

The MCP42010.ino sketch is a simple test that drives the two wiper outputs with complementary triangle waves. This is what it looks like on a scope:



I have the MCP42010 in a 14-Lead SOIC package, so I loaded it on an adapter for breadboard tests..





Credits and References

About LEAP#264 ArduinoDigital PotMCP42010
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LEAP is my personal collection of electronics projects, usually involving an Arduino or other microprocessor in one way or another. Some are full-blown projects, while many are trivial breadboard experiments, intended to learn and explore something interesting (IMHO!).

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