When global interrupts are disabled (GIE cleared) and any interrupt source, with the exception of the clock switch interrupt, has both its interrupt enable bit and interrupt flag bit set, one of the following will occur:
SLEEP
instructionSLEEP
instruction will execute as a
NOP
SLEEP
instructionSLEEP
instruction will be completely
executedIn the event where flag bits were checked before executing a
SLEEP
instruction, it may be possible for flag bits to have 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
.
1
assumed. In
this case after wake-up, the processor calls the ISR at 0x0004
. If
GIE = 0
, execution will continue in-line.