Datasheet

 2002 Microchip Technology Inc. Preliminary DS39598C-page 93
PIC16F818/819
12.9 Power Control/Status Register
(PCON)
The Power Control/Status Register, PCON, has two
bits to indicate the type of RESET that last occurred.
Bit0 is Brown-out Reset Status bit, BOR. Bit BOR is
unknown on a Power-on Reset. It must then be set by
the user and checked on subsequent RESETS to see
if bit BOR
cleared, indicating a Brown-out Reset
occurred. When the Brown-out Reset is disabled, the
state of the BOR bit is unpredictable.
Bit1 is POR
(Power-on Reset Status bit). It is cleared on
a Power-on Reset and unaffected otherwise. The user
must set this bit following a Power-on Reset.
TABLE 12-1: TIME-OUT IN VARIOUS SITUATIONS
TABLE 12-2: STATUS BITS AND THEIR SIGNIFICANCE
TABLE 12-3: RESET CONDITION FOR SPECIAL REGISTERS
Oscillator Configuration
Power-up Brown-out Reset
Wake-up from
SLEEP
PWRTE
= 0 PWRTE = 1 PWRTE = 0 PWRTE = 1
XT, HS, LP T
PWRT +
1024 • T
OSC
1024 • TOSC TPWRT +
1024 • T
OSC
1024 • TOSC 1024 • TOSC
EXTRC, EXTCLK, INTRC TPWRT 5 - 10 µs
(1)
TPWRT 5 - 10 µs
(1)
5 - 10 µs
(1)
Note 1: CPU start-up is always invoked on POR, BOR and wake-up from SLEEP.
POR BOR TO PD
0x11Power-on Reset
0x0xIllegal, TO is set on POR
0xx0Illegal, PD is set on POR
1011Brown-out Reset
1101WDT Reset
1100WDT Wake-up
11uuMCLR
Reset during normal operation
1110MCLR Reset during SLEEP or interrupt wake-up from SLEEP
Legend: u = unchanged, x = unknown
Condition
Program
Counter
STATUS
Register
PCON
Register
Power-on Reset 000h 0001 1xxx ---- --0x
MCLR
Reset during normal operation 000h 000u uuuu ---- --uu
MCLR
Reset during SLEEP 000h 0001 0uuu ---- --uu
WDT Reset 000h 0000 1uuu ---- --uu
WDT Wake-up PC + 1 uuu0 0uuu ---- --uu
Brown-out Reset 000h 0001 1uuu ---- --u0
Interrupt wake-up from SLEEP PC + 1
(1)
uuu1 0uuu ---- --uu
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).