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M16C/64A 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 any area
other than the flash memory. Figure 9.3 shows the setting procedure to stop and restart the flash
memory. Follow the flowchart of Figure 9.3.
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 9.3
Stop and Restart of the Flash Memory
R01UH0136EJ0210 Rev.2.10
Jul 31, 2012
Start
Transfer the program within the dashed line below to
an area other than the flash memory.
Jump to the program transferred to an area other
than the flash memory. (Execute the following steps
in an area other than the flash memory.).
Set the FMR01 bit to 0 first, and then set it to 1 (CPU
rewrite mode enabled).
Set the FMSTP bit to 1 (The flash memory stops
(1)
operating, low-power state)
Switch clock sources of the CPU clock.
(2)
Main clock stop, etc.
Processing
Wait until
Start oscillating
oscillation
main clock
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
Switch clock
source of
(2)
the CPU clock
Restart Procedure
(3)
9. Power Control
Page 125 of 800
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