PIC16C62B/72A
Table 10-5 shows the reset conditions for the STATUS,
PCON and PC registers, while Table 10-6 shows the
reset conditions for all the registers.
10.8
Time-out Sequence
When a POR reset occurs, the PWRT delay starts (if
enabled). When PWRT ends, the OST counts 1024
oscillator cycles (LP, XT, HS modes only). When OST
completes, the device comes out of reset. The total
time-out will vary based on oscillator configuration and
the status of the PWRT. For example, in RC mode with
the PWRT disabled, there will be no time-out at all.
10.9
Power Control/Status Register
(PCON)
The BOR bit is unknown on Power-on Reset. If the
Brown-out Reset circuit is used, the BOR bit must be
set by the user and checked on subsequent resets to
see if it was cleared, indicating a Brown-out has
occurred.
If MCLR is kept low long enough, the time-outs will
expire. Bringing MCLR high will begin execution imme-
diately. This is useful for testing purposes or to synchro-
nize more than one PIC16CXXX device operating in
parallel.
POR (Power-on Reset Status bit) is cleared on a
Power-on Reset and unaffected otherwise. The user
Status Register
IRP
RP1
RP0
TO
PD
Z
DC
C
PCON Register
POR
BOR
TABLE 10-3
TIME-OUT IN VARIOUS SITUATIONS
Power-up
Wake-up from
SLEEP
Oscillator Configuration
Brown-out
PWRTE = 0
72 ms + 1024TOSC
72 ms
PWRTE = 1
1024TOSC
—
XT, HS, LP
RC
72 ms + 1024TOSC
1024TOSC
72 ms
—
TABLE 10-4
STATUS BITS AND THEIR SIGNIFICANCE
POR
BOR
TO
PD
0
0
0
1
1
1
1
1
x
x
x
0
1
1
1
1
1
0
x
1
0
0
u
1
1
x
0
1
1
0
u
0
Power-on Reset
Illegal, TO is set on POR
Illegal, PD is set on POR
Brown-out Reset
WDT Reset
WDT Wake-up
MCLR Reset during normal operation
MCLR Reset during SLEEP or interrupt wake-up from SLEEP
TABLE 10-5
RESET CONDITION FOR SPECIAL REGISTERS
Program
Counter
STATUS
Register
PCON
Register
Condition
Power-on Reset
000h
000h
0001 1xxx
000u uuuu
0001 0uuu
0000 1uuu
uuu0 0uuu
0001 1uuu
uuu1 0uuu
---- --0x
---- --uu
---- --uu
---- --uu
---- --uu
---- --u0
---- --uu
MCLR Reset during normal operation
MCLR Reset during SLEEP
WDT Reset
000h
000h
WDT Wake-up
PC + 1
000h
Brown-out Reset
Interrupt wake-up from SLEEP
PC + 1(1)
Legend: u= unchanged, x= unknown, -= unimplemented bit read as '0'.
Note 1: When the wake-up is due to an interrupt and the GIE bit is set, the PC is loaded with the interrupt vector (0004h).
DS35008B-page 60
Preliminary
1999 Microchip Technology Inc.
MICROCHIP [ MICROCHIP ]
