This is just a little demo on how to use an I²C OLED with the limited capabilities of an ATtiny10, ATtiny13A or ATtiny202 from Stefan Wagner @ github.com
Connect the OLED module to the ATtiny13A as shown below. The connections for the ATtiny10 are similar. For the ATtiny202 SDA must be connected to PA1 (pin 4) and SCL (or SCK) to PA2 (pin 5).
Since the I²C implementation for ATtiny10/13A is software-based, you can of course use any other I/O pins instead. Just change the relevant definitions in the code. The implementation for the ATtiny202 uses hardware TWI, so the pins provided for this must be used.
more details: https://github.com/wagiminator/ATtiny13-TinyOLEDdemo