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TinyWireMCP23008 - MCP23008 library for ATtiny85 microcontroller

TinyWireMCP23008 is a library that ease the use of the MCP23008 I2C port expander with an ATtiny85 microcontroller.


If you want to know more…

If you want to know more about ATtiny85 microcontroller and how to upload sketches to it, you may have a look to ATtiny85 vs ATmega328.


TinyWireMCP23008 was tested (and works) with a 8 MHz ATtiny85 and I2C standard bus mode and I2C fast bus mode.
TinyWireMCP23008 was not tested with ATtiny85 other frequencies, but should work (I can't guarantee that fast bus mode will work with a 1 MHz ATtiny85).

If you need to use this library on an ATtiny85 which is not running at 8 MHz, or don't want/need to use fast mode, all details on how to change theses settings are into the file on GitHub repository.

TinyWireMCP23008 should work with other ATtiny microcontrollers.

TinyWireMCP23008 provides an example sketch to show how to use the library.


Example provided with TinyWireMCP23008 use few items:

  • An ATtiny85 microcontroller.
  • An MCP23008 I2C port expander.
  • A 330Ω resistor.
  • Two 4.7kΩ resistors (pull up resistors for I2C lines).
  • A LED.

The breadboard assembly and schematics

Breadboard assembly


Schematics and code are available on GitHub.

Download on GitHub

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