Determining the Cause of a Reset

Upon any Reset, multiple bits in the STATUS and PCON0 registers are updated to indicate the cause of the Reset. The following table shows the Reset conditions of these registers.

Table 1. Reset Condition for Special Registers
Condition Program
Counter STATUS




Power-on Reset 0 -110 0000 0011 110x
Brown-out Reset 0 -110 0000 0011 11u0
MCLR Reset during normal operation 0 -uuu uuuu uuuu 0uuu
MCLR Reset during Sleep 0 -10u uuuu uuuu 0uuu
WDT Time-out Reset 0 -0uu uuuu uuu0 uuuu
WDT Wake-up from Sleep PC + 2 -00u uuuu uuuu uuuu
WWDT Window Violation Reset 0 -uuu uuuu uu0u uuuu
Interrupt Wake-up from Sleep PC + 2(1) -10u 0uuu uuuu uuuu
RESET Instruction Executed 0 -uuu uuuu uuuu u0uu
Stack Overflow Reset (STVREN = 1) 0 -uuu uuuu 1uuu uuuu
Stack Underflow Reset (STVREN = 1) 0 -uuu uuuu u1uu uuuu
Data Protection (Fuse fault) 0 ---u uuuu uuuu uuuu
VREG or ULP Ready fault 0 ---1 1000 0011 001u

Legend: u = unchanged, x = unknown, — = unimplemented bit, reads as ‘0’.

  1. 1.When the wake-up is due to an interrupt and Global Interrupt Enable bit (GIE) is set, the return address is pushed on the stack and PC is loaded with the corresponding interrupt vector (depending on source, high or low priority) after execution of PC + 2.
  2. 2.If a Status bit is not implemented, that bit will be read as ‘0’.
  3. 3.Status bits Z, C, DC are reset by POR/BOR.