Fujitsu MB91150 Series, Hardware Manual, Page: 103 / 512

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CHAPTER 3 MEMORY SPACE, CPU AND CONTROL UNIT
3.12 Low-Power Consumption Mode
The low-power consumption mode has stop and sleep statuses.
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Overview of the stop status
The stop status means a state in which all internal clocks and oscillation circuit operation
(except 32 kHz oscillation) are stopped. It can minimize power consumption.
To enter the stop status, use an instruction to write to the standby control register (STCR).
To return from the stop status, use one of the following methods:
• Set an interrupt request (However, there are restrictions with respect to the peripherals that
can generate interrupt requests even in stop status.)
• Applying the L level to the RST pin
In stop status, all internal clocks stop. In this state, built-in peripherals other than those that can
generate a return interrupt enter stop status.
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Overview of the sleep status
The sleep status means a status in which the CPU clock and internal bus clock are stopped. It
can suppress power consumption to some extent in a situation in which no CPU operation is
required.
To enter the sleep status, use an instruction to write to the standby control register (STCR).
To return from the sleep status, use one of the following methods:
• Setting an interrupt request
• Generate a reset source
In sleep status, operation of the peripheral clock resumes. This allows releasing an interrupt
caused by the built-in circuits for peripherals.