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CHAPTER 3 CLOCK GENERATOR AND CONTROLLER
[Example of setting the maximum gear speed]
■
Returning from the Sleep State
An interrupt or resetting can be used to return from the sleep state.
❍
Return by way of an interrupt
When the enable bit for the interrupt, which is one of the peripheral functions, is on, a peripheral
interrupt can be used to return from the sleep state.
The procedure for returning from the stop state to the normal run state is as follows:
Interrupt generation --> restart of internal bus clock supply --> restart of internal CPU
clock supply
Program execution after clock supply is as follows:
• When the level of the caused interrupt is enabled by the I flag of CPU ILM
• The program saves the register, fetches the interrupt vector, and executes processing
beginning from the interrupt processing routine.
• When the level of the caused interrupt is disabled by the I flag of CPU ILM
• The program executes instructions beginning from the instruction following the instruction
that caused transition to the sleep state.
❍
Return by way of a reset request
The procedure for returning from the stop state to the normal run state is as follows:
Occurrence of internal reset --> restart of internal bus clock supply --> restart of internal
CPU clock supply --> reset vector fetch --> restart of instruction execution from reset
entry address
<Notes>
• When a peripheral interrupt is used as a DMA transfer request, the interrupt cannot be used
to return from the sleep state.
• If a peripheral interrupt request has already been issued when the STCR register bits 7 and
6 are written, transition to the sleep state does not occur. If a DMA request and sleep
LDI:20 #GCR,R0
LDI:8 #00000011b,R1 ; CHC=1,CPU=peripheral gear ratio
STB R1,@R0 ; If DBLON=0
LDI:20 #STCR,R0
LDI:8 #01010000b,R1 ; SLEP=1
STB R1,@R0
NOP ;
NOP ;
NOP ;
NOP ;
NOP ;
NOP ;