Overview

Driver for a Microchip MCP23008 (I2C) or MCP23S08 (SPI) bus expander..

The MCP23008 is a 8-bit I2C port expander and the MCP23S08 is an 8-bit SPI port expander where each of the bits can function as either an input or an output.

Resources

All correct at time of writing, but as always, manufacturers love to move things around on their website.

Web page

MCP23008

http://www.microchip.com/wwwproducts/Devices.aspx?dDocName=en021393

MCP23S08

http://www.microchip.com/wwwproducts/Devices.aspx?dDocName=en021817

Datasheet

http://www.microchip.com/downloads/en/DeviceDoc/21919e.pdf

Test hardware

This code has been tested using a SolderCore controlling a SenseCore.

http://www.soldercore.com/

API Summary

Constants
MCP23008_I2C_ADDR	8-bit I2C address for MC23008
Functions
mcp23x08_initialize_i2c	Initialize bus expander on I2C bus
mcp23x08_initialize_spi	Initialize bus expander on SPI bus