M16C65 Datasheet, PDF (181/829 Pages) Renesas Technology Corp – RENESAS MCU M16C FAMILY / M16C/60

Under development
M16C/65 Group
Preliminary Specification
This is a preliminary specification and is subject to change.
9. Power Control
9.4 Power Control in Flash Memory
9.4.1 Stopping Flash Memory
When the flash memory is stopped, consumption current is reduced. Execute a program in any area
other than the flash memory. Figure 9.2 shows Stop and Restart of the Flash Memory. Follow the
flowchart of Figure 9.2.
Transfer the program within the dashed line below to an
area other than the flash memory
Jump to the program within the dashed line below
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 operating,
low-power state) ⁽¹⁾
Switch clock sources of the CPU clock.
Main clock stop, 40 MHz on-chip oscillator stop, etc. ⁽²⁾
Processing ⁽⁴⁾
Start oscillating main
clock or 40 MHz
on-chip oscillator
Wait until
oscillation
stabilizes
Switch clock
source of
the CPU clock ⁽²⁾
Set the FMSTP bit to 0 (flash memory operation).
Stop Procedure
Set the FMR01 bit to 0 (CPU rewrite mode disabled).
Restart Procedure
Wait until the flash memory stabilizes (tps). ⁽³⁾
Jump to the desired address in the flash memory.
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.
4. To enter stop mode or wait mode, set the FMR01 bit to 0 (CPU rewrite mode disabled).
Stop and Restart of the Flash Memory
REJ09B0484-0030 Rev.0.30 Sep 09, 2008
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