20.3.2.1 Reset Sources

After any Reset, the source that caused the Reset is found in the Reset Flag (RSTFR) register. The user can identify the previous Reset source by reading this register in the software application.

There are four types of Resets based on the source:
  • Power Supply Reset Sources:
    • Power-on Reset (POR)
    • Brown-out Detector (BOD) Reset
  • User Reset Sources:
    • External Reset (RESET)
    • Watchdog Timer (WDT) Reset
    • Software Reset (SWRST)
    • Unified Program and Debug Interface (UPDI) Reset
  • Error Controller Reset
  • Machine Check Reset:
    • Voltage Regulator Monitor
    • CRCSCAN failed
    • WDT clock failure
    • Boot process error
    • Dual-core lockstep CPU error
    • Error Controller internal error
    • Design-For-Test mechanism enabled error
    • On-Chip debug system enabled error
    • UPDI Illegal Bus Activity Detected
    • Clock Failure Detected