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CHAPTER 3 CLOCK GENERATOR AND CONTROLLER
3.10 Standby Mode (Low Power Consumption Mechanism)
The standby mode implies the stop state and sleep state.
■
Outline of Stop State
In the stop state, all internal clocks and the operation of the oscillation circuit are stopped so as
to minimize power consumption.
Proceed as follows to shift to the stop state:
•
Using an instruction to write to the standby control register (STCR)
Perform one of the following to return to the operating state:
•
Interrupt request (limited to the peripherals that permit an interrupt request to occur even in
the stop state)
•
Applying the L level to the RSTX pin
Since all internal clocks are stopped in the stop state, internal peripherals other than those that
cause an interrupt to return remain stopped.
■
Outline of Sleep State
In the sleep state, the CPU clock and internal bus clock are stopped. Power consumption when
CPU operation is not required can be suppressed to a certain degree.
Proceed as follows to transit to the sleep state:
•
Using an instruction to write to the standby control register (STCR)
Perform one of the following to to return to the operating state:
•
Interrupt request
•
Issue a reset cause
Since the internal DMA clock and peripheral clock operate in the sleep state, the sleep state can
be canceled by causing an interrupt from any of the internal peripherals that use one of the two
clock sources.
■
Types of Operation in Standby Mode
Table 3.10.1 lists the types of operations performed in standby mode.
Y: Operating X: Stopped
Table 3.10-1 Types of Operation in Standby Mode
Operating
status
Transition
condition
Oscillator
Internal clock
Peripheral
Pin
Cancel
method
CPU/
internal bus
DMA/
peripheral
Run
Y
Y
Y
Y
Active
Sleep
STCR
SLEP = 1
Y
X
Y
Y
Active
Stop
STCR
STOP = 1
X
X
X
X
*
Summary of Contents for MB91F109
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Page 96: ...72 CHAPTER 2 CPU ...
Page 224: ...200 CHAPTER 4 BUS INTERFACE ...
Page 234: ...210 CHAPTER 5 I O PORTS ...
Page 268: ...244 CHAPTER 9 U TIMER ...
Page 290: ...266 CHAPTER 10 UART ...
Page 314: ...290 CHAPTER 12 16 BIT RELOAD TIMER ...
Page 322: ...298 CHAPTER 13 BIT SEARCH MODULE ...
Page 392: ...368 CHAPTER 16 FLASH MEMORY ...
Page 432: ...408 APPENDIX E Instructions F Table E 2 Instruction Formats OP rel11 5 11 ...
Page 448: ...424 APPENDIX E Instructions ...
Page 449: ...425 INDEX INDEX The index follows on the next page This is listed in alphabetic order ...
Page 458: ...434 INDEX ...
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