r5f21368sdfp Renesas Electronics Corporation., r5f21368sdfp Datasheet - Page 154

• Manufacturer Part Number: r5f21368sdfp
• Description: Renesas Mcu R8c Family / R8c/3xt-a Series
• Manufacturer: Renesas Electronics Corporation.

Under development
R8C/36T-A Group
R01UH0240EJ0001 Rev.0.01
Apr 28, 2011
Figure 10.6
10.6.10 Stopping Flash Memory
FMR01, FMSTP: Bits in FMR0 register
Notes:
1. Set the FMR01 bit to 1 (CPU rewrite mode enabled) and then set the
2. When switching the clock source for the CPU clock, the new clock
3. Provide a wait time of 60  s by a program.
In low-speed clock mode and low-speed on-chip oscillator mode, the flash memory can be stopped using the
FMSTP bit in the FMR0 register to further reduce the power consumption.
When the FMSTP bit is set to 1 (flash memory stops), the flash memory cannot be accessed. The FMSTP bit
must be written by a program that has been transferred to the RAM.
When entering stop mode or wait mode with CPU rewrite mode disabled, the power supply for the flash
memory is automatically turned off. It is turned on again when the MCU exits stop mode or wait mode. This
eliminates the need to set the FMR0 register.
Figure 10.6 shows the Procedure for Reducing Power Consumption Using FMSTP Bit.
FMSTP bit to 1.
must be stable.
Do not access the flash memory during this wait time.
(The subsequent processing is executed
Transfer the FMSTP bit setting program
Jump to the FMSTP bit setting program
by the program in the RAM)
Preliminary document
Specifications in this document are tentative and subject to change.
Procedure for Reducing Power Consumption Using FMSTP Bit
to the RAM
FMSTP bit setting program
Write 0 to the FMSTP bit (flash memory operates)
Write 1 to the FMSTP bit (flash memory stops.
Switch the clock source for the CPU clock
Wait until the flash memory circuit stabilizes
Enter low-speed clock mode or low-speed
After writing 0 to the FMR01 bit, write 1
Stop the high-speed on-chip oscillator
Process in low-speed clock mode or
low-speed on-chip oscillator mode
low power consumption state)
Jump to the specified address
(CPU rewrite mode disabled)
(CPU rewrite mode enabled)
Write 0 to the FMR01 bit
on-chip oscillator mode
in the flash memory
(60  s)
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10. Power Control
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