I2C Master at attiny84


I'm searching for a way to add i2c commincation ability on my Attiny84(best would be to be able to use the i2c like it's possible with the wire library...). If read several time that the TinyWireM i'd like to use doesn't support that attiny84.

I've read there were modified versions but i can't find a working link anymore. I just like to get the time of a RTC and to control a mcp23017 port expander with I2c / TWI.

Can somebody help me?


Attiny84 does support I2C with SDA pin physical pin 7/PA6 and SCL on physical pin 9/PA4.

Just need to find the right core for it. Maybe go to a slighty larger part, Attiny2313/4313 (20 pin vs 14 pin) and use Hansibull's Microcore? https://github.com/MCUdude/MicroCore