A software IIC/I2C library aimed at the arduino/atmega platform. Master and multi-slave supported.

SoftIIC is a class which enables easy communication to other IIC devices, as a master or slave, or in the presence of other masters.

Master mode features:

With a 16MHz core clock, 100KHz IIC master is supported. Slower core clocks may also work.

Can tolerate the presence of other masters in most cases. (Safety not guaranteed)

The bus-restart functionality is supported.

Multi-byte reads and writes are supported.

Clock stretching in master mode is not supported yet.

Slave mode features:

With a 16MHz core clock, 100KHz IIC slave is supported. This is about the limit of operation.

Multiple simultaneous slave addresses are supported.

Function callback system for granular ACK/NACK support.

The bus-restart functionality is supported.

Multi-byte reads and writes are supported.

Clock stretching in slave mode is not supported/used.

Timeouts ensure system reliability.

SoftIIC requires: Timer1 Two I/O pins on the same port (for simultaneous sampling)

SoftIIC currently is tested on: Atmega168