9.11 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.
| Condition | Program Counter | STATUS Register(2,3) | PCON0 Register |
|---|---|---|---|
| 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’.
Note:
- When the wake-up is due to an interrupt and the Global Interrupt Enable (GIE) bit is set, the return address is pushed on the stack and the PC is loaded with the corresponding interrupt vector (depending on source, high or low priority) after execution of PC + 2.
- If a Status bit is not implemented, that bit will be read as
‘
0’. - Status bits Z, C, DC are reset by POR/BOR.