PIC16F/LF1946/47
9.1
Wake-up from Sleep
9.0
POWER-DOWN MODE (SLEEP)
The device can wake-up from Sleep through one of the
following events:
The Power-down mode is entered by executing a
SLEEPinstruction.
1. External Reset input on MCLR pin, if enabled
2. BOR Reset, if enabled
Upon entering Sleep mode, the following conditions
exist:
3. POR Reset
1. WDT will be cleared but keeps running, if
enabled for operation during Sleep.
4. Watchdog Timer, if enabled
5. Any external interrupt
2. PD bit of the STATUS register is cleared.
3. TO bit of the STATUS register is set.
4. CPU clock is disabled.
6. Interrupts by peripherals capable of running dur-
ing Sleep (see individual peripheral for more
information)
5. 31 kHz LFINTOSC is unaffected and peripherals
that operate from it may continue operation in
Sleep.
The first three events will cause a device Reset. The
last three events are considered a continuation of pro-
gram execution. To determine whether a device Reset
or wake-up event occurred, refer to Section 6.10
“Determining the Cause of a Reset”.
6. Timer1 oscillator is unaffected and peripherals
that operate from it may continue operation in
Sleep.
7. ADC is unaffected, if the dedicated FRC clock is
selected.
When the SLEEPinstruction is being executed, the next
instruction (PC + 1) is prefetched. For the device to
wake-up through an interrupt event, the corresponding
interrupt enable bit must be enabled. Wake-up will
occur regardless of the state of the GIE bit. If the GIE
bit is disabled, the device continues execution at the
instruction after the SLEEPinstruction. If the GIE bit is
enabled, the device executes the instruction after the
SLEEP instruction, the device will call the Interrupt
Service Routine. In cases where the execution of the
instruction following SLEEP is not desirable, the user
should have a NOPafter the SLEEPinstruction.
8. Capacitive Sensing oscillator is unaffected.
9. I/O ports maintain the status they had before
SLEEPwas executed (driving high, low or high-
impedance).
10. Resets other than WDT are not affected by
Sleep mode.
Refer to individual chapters for more details on
peripheral operation during Sleep.
To minimize current consumption, the following condi-
tions should be considered:
The WDT is cleared when the device wakes up from
Sleep, regardless of the source of wake-up.
• I/O pins should not be floating
• External circuitry sinking current from I/O pins
• Internal circuitry sourcing current from I/O pins
• Current draw from pins with internal weak pull-ups
• Modules using 31 kHz LFINTOSC
• Modules using Timer1 oscillator
I/O pins that are high-impedance inputs should be
pulled to VDD or VSS externally to avoid switching
currents caused by floating inputs.
Examples of internal circuitry that might be sourcing
current include modules such as the DAC and FVR
modules. See Section 16.0 “Digital-to-Analog Con-
verter (DAC) Module” and Section 14.0 “Fixed Volt-
age Reference (FVR)” for more information on these
modules.
2010 Microchip Technology Inc.
Preliminary
DS41414A-page 101
MICROCHIP [ MICROCHIP ]
