r5f21346mnfp Renesas Electronics Corporation., r5f21346mnfp Datasheet - Page 162

• Manufacturer Part Number: r5f21346mnfp
• Description: Single-chip Mcus Incorporates The R8c Cpu Core
• Manufacturer: Renesas Electronics Corporation.

R8C/34M Group
R01UH0131EJ0100 Rev.1.00
Jun 21, 2011
9.7.2
9.7.2.1
9.7.2.2
9.7.2.3
9.7.2.4
Since the CPU clock stops in wait mode, the CPU operating with the CPU clock and the watchdog timer when
count source protection mode is disabled stop. Since the XIN clock, XCIN clock, and on-chip oscillator clock
do not stop, the peripheral functions using these clocks continue operating.
If the CM02 bit is set to 1 (peripheral function clock stops in wait mode), the f1, f2, f4, f8, and f32 clocks stop
in wait mode. This reduces power consumption.
The MCU enters wait mode by executing the WAIT instruction or setting the CM30 bit in the CM3 register to 1
(MCU enters wait mode).
When the OCD2 bit in the OCD register is set to 1 (on-chip oscillator selected as system clock), set the OCD1
bit in the OCD register to 0 (oscillation stop detection interrupt disabled) before executing the WAIT
instruction or setting the CM30 bit in the CM3 register to 1(MCU enters wait mode).
If the MCU enters wait mode while the OCD1 bit is set to 1 (oscillation stop detection interrupt enabled),
current consumption is not reduced because the CPU clock does not stop.
When entering wait mode, set the FMR01 bit in the FMR0 register to 0 (CPU rewrite mode disabled) and the
FMR27 bit to 0 (low-current-consumption read mode disabled) before entering the mode.
Do not enter wait mode while the FMR01 bit is 1 (CPU rewrite mode enabled) or the FMR27 bit is 1 (low-
current-consumption read mode enabled).
To enter wait mode by setting the CM30 bit to 1, set the I flag to 0 (maskable interrupt disabled). To enter wait
mode using the WAIT instruction, set the I flag to 1 (maskable interrupt enabled).
When the MCU enters wait mode using low-speed clock mode or low-speed on-chip oscillator mode, internal
power consumption can be reduced using the VCA20 bit in the VCA2 register. To enable internal power
consumption using the VCA20 bit, follow the procedure shown in 33.2.9 Procedure for Reducing Internal
Power Consumption Using VCA20 Bit.
The I/O port retains the status immediately before the MCU enters wait mode.
Wait Mode
Peripheral Function Clock Stop Function
Entering Wait Mode
Reducing Internal Power Using VCA20 Bit
Pin Status in Wait Mode
9. Clock Generation Circuit
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