Datasheet

 2012 Microchip Technology Inc. Preliminary DS41652A-page 53
PIC16F527
8.10 Power-down Mode (Sleep)
A device may be powered down (Sleep) and later
powered up (wake-up from Sleep).
8.10.1 SLEEP
The Power-Down mode is entered by executing a
SLEEP instruction.
If enabled, the Watchdog Timer will be cleared but
keeps running, the TO
bit of the STATUS register is set,
the PD
bit of the STATUS register is cleared and the
oscillator driver is turned off. The I/O ports maintain the
status they had before the SLEEP instruction was exe-
cuted (driving high, driving low or high-impedance).
For lowest current consumption while powered down,
the T0CKI input should be at V
DD or VSS and the
M
CLR/VPP pin must be at a logic high level if MCLR is
enabled.
8.10.2 WAKE-UP FROM SLEEP
The device can wake-up from Sleep through one of
the following events:
1. An external Reset input on RB3/MCLR
/VPP pin,
when configured as MCLR
.
2. A Watchdog Timer Time-out Reset (if WDT was
enabled).
3. From an interrupt source, see Section 8.11
“Interrupts” for more information.
On waking from Sleep, the processor will continue to
execute the instruction immediately following the
SLEEP instruction. If the WUR bit is also set, upon
waking from Sleep, the device will reset. If the GIE bit
is also set, upon waking from Sleep, the processor will
branch to the interrupt vector. Please see
Section 8.11 “Interrupts” for more information.
The TO
and PD bits can be used to determine the
cause of the device Reset. The TO
bit is cleared if a
WDT time-out occurred and subsequently caused a
wake-up. The PD bit, which is set on power-up, is
cleared when SLEEP is invoked.
.
The WDT is cleared when the device wakes from
Sleep, regardless of the wake-up source.
Note: A Reset generated by a WDT time-out
does not drive the MCLR
pin low.
Note: Caution: Right before entering Sleep,
read the input pins. When in Sleep, wake-
up occurs when the values at the pins
change from the state they were in at the
last reading. If a wake-up on change
occurs and the pins are not read before
re-entering Sleep, a wake-up will occur
immediately even if no pins change while
in Sleep mode.
Note: Caution: Right before entering Sleep,
read the comparator Configuration
register(s) CM1CON0 and CM2CON0.
When in Sleep, wake-up occurs when the
comparator output bit C1OUT and
C2OUT change from the state they were
in at the last reading. If a wake-up on com-
parator change occurs and the pins are
not read before re-entering Sleep, a wake-
up will occur immediately, even if no pins
change while in Sleep mode.