I've designed a board (HAT) that uses the ATmega328P microcontroller, and I think I might have made some mistakes in the board design. The design is most like the Arduino Pro mini, but with a 5A dual channel H-bridge, running at 3.3V 16MHz, and using the Raspberry Pi as the power source.
Arduino Pro Mini: https://www.arduino.cc/en/uploads/Main/Arduino-Pro-Mini-schematic.pdf
1) Do I have to have C3? I think it's for power stability and needs to be put next to the microcontroller, but I'm really not sure and want to eliminate it as a possibility as to which part made the board fail.
2) Do I need C2 if I'm not using the DTR Pin?
3) I assume that I don't need C13 and C10 because I'm getting power from the Pi, but can someone confirm?
If it helps, when I boot the raspberry pi, the serial port comes up, but I am totally incapable of communicating. Are there other components that I'm missing?