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M16C/5L Group, M16C/56 Group
9.4
Power Control in Flash Memory
9.4.1
Stopping Flash Memory
When the flash memory is stopped, current consumption is reduced. Execute a program in the RAM.
Figure 9.2 shows the setting procedure to stop and restart the flash memory. Follow the flowchart of
Figure 9.2.
Notes:
1. Set the FMSTP bit to 1 after the FMR01 bit is set to 1 (CPU rewrite mode enabled).
2. Wait until the clock stabilizes before switching the clock source of the CPU clock.
3. Add tps wait time by a program. Do not access the flash memory during this wait time.
Figure 9.2
Stop and Restart of the Flash Memory
R01UH0127EJ0110 Rev.1.10
Sep 01, 2011
Start
Transfer the program within the dashed line below to
the RAM.
Jump to the program transferred to the RAM.
Set the FMR01 bit to 0 first, and then set it to 1 (CPU
rewrite mode enabled).
Set the FMSTP bit to 1 (flash memory stops operating,
(1)
low-power state)
Switch clock sources of the CPU clock.
Main clock stop, 40 MHz on-chip oscillator stop, etc.
Processing
Start oscillating main
Wait until
clock or 40 MHz
oscillation
on-chip oscillator
stabilizes
Set the FMSTP bit to 0 (flash memory operation).
Set the FMR01 bit to 0 (CPU rewrite mode disabled).
Wait until the flash memory stabilizes (tps).
Jump to the desired address in the flash memory.
End
Stop Procedure
(2)
Switch clock
source of
(2)
the CPU clock
Restart Procedure
(3)
9. Power Control
Page 133 of 803
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