PIC18F45J10 Datasheet, PDF (44/358 Pages) Microchip Technology – 28/40/44-Pin High-Performance RISC Microcontrollers with nanoWatt Technology

PIC18F45J10 FAMILY
4.6 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, RI, TO,
PD, POR and BOR, are set or cleared differently in
different Reset situations, as indicated in Table 4-1.
These bits are used in software to determine the nature
of the Reset.
Table 4-2 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.
TABLE 4-1: STATUS BITS, THEIR SIGNIFICANCE AND THE INITIALIZATION CONDITION FOR
RCON REGISTER
Condition
Program
Counter⁽¹⁾
RI
RCON Register
STKPTR Register
TO
PD POR BOR⁽²⁾ STKFUL STKUNF
Power-on Reset
0000h
1
1
1
0
0
0
0
RESET instruction
0000h
0
u
u
u
u
u
u
Brown-out
0000h
1
1
1
u
0
u
u
MCLR during power-managed
0000h
u
1
u
u
u
u
u
Run modes
MCLR during power-managed
0000h
u
1
0
u
u
u
u
Idle modes and Sleep mode
WDT time-out during full power
0000h
u
0
u
u
u
u
u
or power-managed Run modes
MCLR during full power
execution
0000h
u
u
u
u
u
u
u
Stack Full Reset (STVREN = 1) 0000h
u
u
u
u
u
1
u
Stack Underflow Reset
(STVREN = 1)
0000h
u
u
u
u
u
u
1
Stack Underflow Error (not an
0000h
u
u
u
u
u
u
1
actual Reset, STVREN = 0)
WDT time-out during
PC + 2
u
0
0
u
u
u
u
power-managed Idle or Sleep
modes
Interrupt exit from
power-managed modes
PC + 2
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 bits are set, the PC is loaded with the
interrupt vector (0008h or 0018h).
2: BOR is not available in PIC18LF2X1X/4X1X devices.
DS39682C-page 42
Preliminary
© 2007 Microchip Technology Inc.