3.1 Non-Responsive I/O

Symptoms:

  • An I/O line does not change
  • An I/O line has an odd waveform

Troubleshooting:

  • Check PPS (for PIC devices), PORTMUX (for AVR8 devices), and hardware (Configuration bit or fuse) settings
  • Verify no hardware functions on the line

I/O problems can be grouped into two categories:
  • Those that arise from a misconfiguration on the microcontroller
  • Those that are external to the microcontroller