PIC16F946 Datasheet, PDF (211/274 Pages) Microchip Technology – 64-Pin Flash-Based, 8-Bit CMOS Microcontrollers with LCD Driver and nanoWatt Technology

PIC16F946
Even if the flag bits were checked before executing a
SLEEP instruction, it may be possible for flag bits to
become set before the SLEEP instruction completes. To
determine whether a SLEEP instruction executed, test
the PD bit. If the PD bit is set, the SLEEP instruction
was executed as a NOP.
To ensure that the WDT is cleared, a CLRWDT instruction
should be executed before a SLEEP instruction.
FIGURE 16-10: WAKE-UP FROM SLEEP THROUGH INTERRUPT
Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4 Q1
OSC1⁽¹⁾
CLKO⁽⁴⁾
Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4
TOST⁽²⁾
INT pin
INTF flag
(INTCON<1>)
Interrupt Latency⁽³⁾
GIE bit
(INTCON<7>)
Processor in
Sleep
Instruction Flow
PC
PC
Instruction
Fetched
Inst(PC) = Sleep
Instruction
Executed
Inst(PC - 1)
PC + 1
Inst(PC + 1)
Sleep
PC + 2
PC + 2
Inst(PC + 2)
Inst(PC + 1)
PC + 2
Dummy Cycle
0004h
Inst(0004h)
Dummy Cycle
0005h
Inst(0005h)
Inst(0004h)
Note 1:
2:
3:
4:
XT, HS or LP Oscillator mode assumed.
TOST = 1024 TOSC (drawing not to scale). This delay does not apply to EC and RC Oscillator modes.
GIE = 1 assumed. In this case after wake-up, the processor jumps to 0004h. If GIE = 0, execution will continue in-line.
CLKO is not available in XT, HS, LP or EC Oscillator modes, but shown here for timing reference.
© 2005 Microchip Technology Inc.
Preliminary
DS41265A-page 209