Datasheet

Table Of Contents
PIC16LF1904/6/7
DS41569A-page 80 Preliminary 2011 Microchip Technology Inc.
8.1.1 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 8-1: WAKE-UP FROM SLEEP THROUGH INTERRUPT
TABLE 8-1: SUMMARY OF REGISTERS ASSOCIATED WITH POWER-DOWN MODE
Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4 Q1
Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4
CLKIN
(1)
CLKOUT
(2)
Interrupt flag
GIE bit
(INTCON reg.)
Instruction Flow
PC
Instruction
Fetched
Instruction
Executed
PC PC + 1 PC + 2
Inst(PC) = Sleep
Inst(PC - 1)
Inst(PC + 1)
Sleep
Processor in
Sleep
Interrupt Latency
(1)
Inst(PC + 2)
Inst(PC + 1)
Inst(0004h)
Inst(0005h)
Inst(0004h)
Dummy Cycle
PC + 2 0004h 0005h
Dummy Cycle
PC + 2
Note 1: GIE = 1 assumed. In this case after wake-up, the processor calls the ISR at 0004h. If GIE = 0, execution will continue in-line.
Name Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0
Register on
Page
INTCON GIE PEIE TMR0IE INTE IOCIE TMR0IF INTF IOCIF 72
IOCBF IOCBF7 IOCBF6 IOCBF5 IOCBF4 IOCBF3 IOCBF2 IOCBF1 IOCBF0 118
IOCBN IOCBN7 IOCBN6 IOCBN5 IOCBN4 IOCBN3 IOCBN2 IOCBN1 IOCBN0 118
IOCBP IOCBP7 IOCBP6 IOCBP5 IOCBP4 IOCBP3 IOCBP2 IOCBP1 IOCBP0 118
PIE1 TMR1GIE ADIE RCIE TXIE
—TMR1IE 73
PIE2
—LCDIE 74
PIR1
TMR1GIF ADIF
RCIF TXIF
TMR1IF
75
PIR2
LCDIF 76
STATUS
—TOPD ZDCC 25
WDTCON
WDTPS<4:0> SWDTEN 83
Legend: — = unimplemented location, read as 0’. Shaded cells are not used in Power-down mode.