PIC16LF1454 Datasheet, PDF (104/418 Pages) Microchip Technology – 14/20-Pin Flash, 8-Bit USB Microcontrollers with XLP Technology

PIC16(L)F1454/5/9
9.1.1 WAKE-UP USING INTERRUPTS
When global interrupts are disabled (GIE cleared) and
any interrupt source has both its interrupt enable bit
and interrupt flag bit set, one of the following will occur:
• If the interrupt occurs before the execution of a
SLEEP instruction
- SLEEP instruction will execute as a NOP.
- WDT and WDT prescaler will not be cleared
- TO bit of the STATUS register will not be set
- PD bit of the STATUS register will not be
cleared.
• If the interrupt occurs during or after the execu-
tion of a SLEEP instruction
- SLEEP instruction will be completely exe-
cuted
- Device will immediately wake-up from Sleep
- WDT and WDT prescaler will be cleared
- TO bit of the STATUS register will be set
- PD bit of the STATUS register will be cleared
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.
FIGURE 9-1:
WAKE-UP FROM SLEEP THROUGH INTERRUPT
Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4 Q1
CLKIN⁽¹⁾
CLKOUT⁽²⁾
Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4
T1OSC⁽³⁾
Interrupt flag
GIE bit
(INTCON reg.)
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
Interrupt Latency⁽⁴⁾
PC + 2
Inst(PC + 2)
Inst(PC + 1)
PC + 2
Forced NOP
0004h
Inst(0004h)
Forced NOP
0005h
Inst(0005h)
Inst(0004h)
Note 1:
2:
3:
4:
External clock. High, Medium, Low mode assumed.
CLKOUT is shown here for timing reference.
T1OSC; See Section 29.0 “Electrical Specifications”.
GIE = 1 assumed. In this case after wake-up, the processor calls the ISR at 0004h. If GIE = 0, execution will continue in-line.
DS41639A-page 104
Preliminary
 2012 Microchip Technology Inc.