MCP4261

A C++ object to control the Microchip MCP4261 Digital Potentiometer. For the Arduino Platform.

UPDATE

• update the library to work with newer Arduino and new SPI

Introduction

Mcp4261 is a simple object which allows your Arduino to control the MCP4261 digital potentiometer, to set wiper positions etc. To use, we just wire up the SPI bus and instantiate a new object. The chip powers up with the wiper state as per the value stored in its non-volatile (EEPROM) memory. This library may also work with other MCP digital potentiometer devices, and/or other AVR microcontroller devices after some tweaking. This library was tested on Arduino UNO.

Features

• Generally fast SPI operation (tested up to 8Mhz)
• Generic example (works with all 328P Arduinos)
• Requires only very minor modifications for Arduino MEGA.
• Can instantiate multiple Mcp4261 objects, each with unique slave select
• Very simple interface and very few configuration
• Works with other devices in this series (see below the Compatability section)
• Individual wiper commands and dual wiper commands as this is a dual (2-channel) potentiometer
• Read/write the potentiometer values as either the nearest rounded wiper resistance (in ohms), or wiper position (0-256).

Requirements

• MCP4261 Product Datasheet*
• The Spi Library by Cam Thompson (not the official one)!

* Sorry, but the previous series of Microchip Digital Potentiometers (any with a total of 5 digits in their name eg 42100) had a very different command syntax and arent supported. They are listed on Page 29 of the previous MCP 4Xxxx Data Sheet.

! Download Cam Thompson's Spi library from the link above. There are several similarly-named versions of this SPI library. The version that comes with the Arduino IDE (SPI.h) isn't going to work.

Getting Started

Pretty much everything is explained within the example sketch file. Open Mcp4261Example.pde in Arduino IDE and upload it to your microcontroller device. Check that all of the SPI interface pins are connected OK for your device.

Dreamcat4

Compatibility

This library is broadly compatible with the other devices in this series. They are: Microchip MCP4131, MCP4132, MCP4231, MCP4232, MCP4141, MCP4142, MCP4241, MCP4242, MCP4151, MCP4152, MCP4251, MCP4252, MCP4161, MCP4162, MCP4261, MCP4262. Just adjust these lines in the header file as appropriate

const static bool         non_volatile    = true;
const static unsigned int resolution      = resolution_8bit;

Credit

• Mcp4261 Version 1 - By Dreamcat4.