The Arduino software comes with an ArduinoISP sketch which allows an Arduino, correctly connected, to flash another AVR chip. With the use of other libraries like Attiny-core, this means you can use ...

Thanks to jaromir-sukuba, and racerxdl for working on firmware to implement C2 protocol via arduino GPIO. This work largely pulls from them, as well as connorpp. C2 is a 2-pin protocol. Any arduino ...