Fujitsu MB90390 Series Hardware Manual page 178

CHAPTER 8 LOW-POWER CONTROL CIRCUIT
■ Release of Sleep Mode
The low-power consumption control circuit releases sleep modes when a reset is input or an interrupt
occurs.
●
Return by a reset
A sleep mode is initialized to the main clock mode by a reset.
●
Return by an interrupt
If an interrupt request of level seven or higher is issued from a peripheral circuit during a sleep mode, the
sleep mode is released. After the mode is released, the interrupt is handled as an ordinary interrupt. If the
interrupt is accepted according to the setting of the I flag of the condition code register (CCR), interrupt
level mask register (ILM), and interrupt control register (ICR), the CPU executes the interrupt processing.
If the interrupt is not accepted, the CPU executes the instruction following the instruction specifying the
sleep mode.
Figure 8.5-1 shows the release of a sleep mode when an interrupt occurs.
Note:
When interrupt processing is executed, the CPU normally executes the instruction that follows the
instruction in which switching to a sleep mode has been specified. The CPU then proceeds to
interrupt processing. If the switching to sleep mode and acceptance of an external bus hold request
occur at the same time, however, the CPU may proceed to interrupt processing before executing the
next instruction.
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Figure 8.5-1 Release of Sleep Mode by Interrupt Occurrence
Interrrupt from peripheral function
Set the enable flag.
IL smaller than 7
NO
INT occurrence?
(IL smaller than 7)
YES
YES
I=0
NO
YES
ILM smaller than IL
NO
Interrupt is executed.
Sleep mode is
not released.
Next instruction
is executed.
Next instruction
is executed.
Sleep mode is
not released.
Sleep mode is
released.