1.1 Start-Up Failure

Symptoms:
  • No microcontroller activity
  • Software is not executed

Troubleshooting:

  • Enable CLKOUT
  • Toggle an I/O pin multiple times at start-up
  • Disable Interrupts
  • Check the RESET or MCLR line
  • Verify that VDD is higher than the minimum operating voltage and brown-out level (if enabled)

Start-up failure is one of the broadest problems possible. Luckily, it’s also one of the most elementary aspects, with few elements on the microcontroller capable of interfering with this process. Many times, the symptoms can be misinterpreted, creating the illusion of this issue. One such example is the Watchdog Timer (WDT) resetting the microcontroller within a few moments of initialization.