Populate ONLY (JP1 and JP2) OR (JP3 and JP4). Select: JP1 and JP2 to enable the "serial hack"orSelect: JP3 and JP3 for exact compatibility withPeggy 2.0.
int InputA0 = A4; int InputA1 = A5;int InputA2 = 2;int InputA3 = 3;
I wanted to connect a Real Time Clock DS3231 to Atmega pins 27 (SDA) and 28 (SCL). I would think I would not be able to do that if using these pins for outputs to HC154.