r5f21368sdfp Renesas Electronics Corporation., r5f21368sdfp Datasheet - Page 151

• 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
10.6
10.6.1
10.6.2
10.6.3
10.6.4
10.6.5
10.6.6
10.6.7
The following describes key points and processing methods for reducing power consumption.
If voltage monitor 1 is not used, set the VCA26 bit in the VCA2 register to 0 (voltage detection 1 circuit
disabled). If voltage monitor 2 is not used, set the VCA27 bit in the VCA2 register to 0 (voltage detection 2
circuit disabled).
If the power-on reset and voltage monitor 0 reset are not used, set the VCA25 bit in the VCA2 register to 0
(voltage detection 0 circuit disabled).
Even after the MCU enters wait mode or stop mode, the states of the I/O ports are retained. Current flows into
the output ports in the active state. Shoot-through current flows into the input ports in the high-impedance state.
Unnecessary ports should be set to input and fixed to a stable electric potential before the MCU enters wait
mode or stop mode.
Power consumption generally depends on the number of the operating clocks and their frequencies. The fewer
the number of operating clocks or the lower their frequencies, the more power consumption decreases.
For that reason, unnecessary clocks should be stopped.
Stopping low-speed on-chip oscillator oscillation: CM14 bit in CM1 register
Stopping high-speed on-chip oscillator oscillation: FRA00 bit in FRA0 register
Power consumption can be reduced in wait mode and stop mode. For details, refer to 10.4 Wait Mode and 10.5
Stop Mode.
CM0 register to 1 (peripheral function clock stops in wait mode). This will stop the f1, f2, f4, f8, and f32 clocks
in wait mode.
When timer RJ is not used, set the corresponding MSTTRJ_0 bit in the MSTCR2 register for the unused timer
RJ to 1 (standby).
When timer RB2 is not used, set the corresponding MSTTRB_0 bit in the MSTCR2 register for the unused
timer RB2 to 1 (standby).
When timer RC is not used, set the corresponding MSTTRC_0 bit in the MSTCR2 register for the unused timer
RC to 1 (standby).
When timer RE2 is not used, set the MSTTRE bit in the MSTCR3 register to 1 (standby).
When the A/D converter is not used, power consumption can be reduced by setting the ADSTBY bit in the
ADCON1 register to 0 (A/D operation stops (standby)) to shut off any analog circuit current flow.
If the peripheral function f1, f2, f4, f8, and f32 clocks are not necessary in wait mode, set the CM02 bit in the
Reducing Power Consumption
Voltage Detection Circuit
Ports
Clocks
Wait Mode, Stop Mode
Stopping Peripheral Function Clocks
Timers
A/D Converter
Preliminary document
Specifications in this document are tentative and subject to change.
10. Power Control
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