Microchip Technology MCU PIC PIC18F87K22-I/PTRSL TQFP-80 MCP PIC18F87K22-I/PTRSL Data Sheet
Product codes
PIC18F87K22-I/PTRSL
PIC18F87K22 FAMILY
DS39960D-page 78
2009-2011 Microchip Technology Inc.
5.7
Reset State of Registers
Most registers are unaffected by a Reset. Their status
is unknown on POR and unchanged by all other
Resets. The other registers are forced to a “Reset
state” depending on the type of Reset that occurred.
Most registers are not affected by a WDT wake-up,
since this is viewed as the resumption of normal
operation. Status bits from the RCON register (CM, RI,
TO, PD, POR and BOR) are set or cleared differently in
is unknown on POR and unchanged by all other
Resets. The other registers are forced to a “Reset
state” depending on the type of Reset that occurred.
Most registers are not affected by a WDT wake-up,
since this is viewed as the resumption of normal
operation. Status bits from the RCON register (CM, RI,
TO, PD, POR and BOR) are set or cleared differently in
These bits are used in software to determine the nature
of the Reset.
of the Reset.
describes the Reset states for all of the
Special Function Registers. These are categorized by
Power-on and Brown-out Resets, Master Clear and
WDT Resets, and WDT wake-ups.
Power-on and Brown-out Resets, Master Clear and
WDT Resets, and WDT wake-ups.
TABLE 5-1:
STATUS BITS, THEIR SIGNIFICANCE AND THE INITIALIZATION CONDITION FOR
RCON REGISTER
RCON REGISTER
Condition
Program
Counter
(
RCON Register
STKPTR Register
CM
RI
TO
PD
POR
BOR
STKFUL
STKUNF
Power-on Reset
0000h
1
1
1
1
0
0
0
0
RESET
instruction
0000h
u
0
u
u
u
u
u
u
Brown-out Reset
0000h
1
1
1
1
u
0
u
u
Configuration Mismatch Reset
0000h
0
u
u
u
u
u
u
u
MCLR Reset during
power-managed Run modes
power-managed Run modes
0000h
u
u
1
u
u
u
u
u
MCLR Reset during power-
managed Idle modes and
Sleep mode
managed Idle modes and
Sleep mode
0000h
u
u
1
0
u
u
u
u
MCLR Reset during full-power
execution
execution
0000h
u
u
u
u
u
u
u
u
Stack Full Reset (STVREN = 1)
0000h
u
u
u
u
u
u
1
u
Stack Underflow Reset
(STVREN = 1)
(STVREN = 1)
0000h
u
u
u
u
u
u
u
1
Stack Underflow Error (not an
actual Reset, STVREN = 0)
actual Reset, STVREN = 0)
0000h
u
u
u
u
u
u
u
1
WDT time-out during full-power
or power-managed Run modes
or power-managed Run modes
0000h
u
u
0
u
u
u
u
u
WDT time-out during
power-managed Idle or Sleep
modes
power-managed Idle or Sleep
modes
PC + 2
u
u
0
0
u
u
u
u
Interrupt exit from
power-managed modes
power-managed modes
PC + 2
u
u
u
0
u
u
u
u
Legend: u
= unchanged
Note 1:
When the wake-up is due to an interrupt and the GIEH or GIEL bit is set, the PC is loaded with the interrupt
vector (0008h or 0018h).
vector (0008h or 0018h).