12.6.3 Reset Flag Register

Name: RSTFLR
Offset: 0x3B
Reset: N/A
Property: -

Bit 76543210 
     WDRF EXTRFPORF 
Access R/WR/WR/W 
Reset xxx 

Bit 3 – WDRF Watchdog Reset Flag

This bit is set if a Watchdog Reset occurs. The bit is reset by a Power-on Reset, or by writing a logic zero to the flag.

Bit 1 – EXTRF External Reset Flag

This bit is set if an External Reset occurs. The bit is reset by a Power-on Reset, or by writing a logic zero to the flag.

Bit 0 – PORF Power-on Reset Flag

This bit is set if a Power-on Reset occurs. The bit is reset only by writing a logic zero to the flag. To make use of the Reset Flags to identify a reset condition, the user should read and then reset the MCUSR as early as possible in the program. If the register is cleared before another reset occurs, the source of the reset can be found by examining the Reset Flags.