Hello. I need to add two buttons and beeper on the MUDI front panel. This all will be connected to Attiny85 microcontroller. Actually, the question is - whither on the MUDI board I can connect the Attiny85? An I2C or SPI bus or at least one free GPIO will be enough.
I don’t believe there is free gpio
On the photos here, you can see pins labeled SDA and SCL. Are these connected to the main CPU somehow? I don’t see any I2C devices in /dev, but the pins are there… Or maybe they are connected to the MCU instead?