Fujitsu F2MC-8L MB89620 Series Hardware Manual page 88

3.7 Standby Modes (Low-power Consumption)
3.7.1 Sleep Mode
This section describes the operations of sleep mode.
n Operation of Sleep Mode
Changing to sleep mode
l
Sleep mode stops the CPU operating clock. The CPU stops while maintaining all register
contents, RAM contents, and pin states at their values immediately prior to entering sleep mode.
However, peripheral functions except the watchdog timer continue to operate.
Writing "1" to the sleep bit in the standby control register (STBC: SLP) changes the CPU to
sleep mode. If an interrupt request is generated when "1" is written to the SLP bit, the write to
the bit is ignored, and the CPU continues the instruction execution without change to sleep
mode. (The CPU does not change to sleep mode even after completion of the interrupt
processing.)
l Wake-up from sleep mode
A reset or an interrupt from a peripheral function wakes up the CPU from sleep mode.
If a reset occurs during sleep mode, the CPU wakes up from sleep mode and the reset
operation also initializes the pin states.
If an interrupt request with an interrupt level higher than "11" occurs from a peripheral function
or an external interrupt circuit during sleep mode, the CPU wakes up from sleep mode,
regardless of the interrupt enable flag (CCR: I) and interrupt level bits (CCR: IL1, IL0) in the
CPU.
The normal interrupt operation is performed after wake-up from sleep mode. If the interrupt
request is accepted, the CPU executes interrupt processing. If the interrupt request is not
accepted, the CPU continues execution from the subsequent instruction following the instruction
executed immediately before changing to sleep mode.
MB89620 series
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CHAPTER 3 CPU