R5F2L3ACBNFP datasheet(199/848 Pages) RENESAS

199 / 848 page

REJ09B0441-0010 Rev.0.10

Jul 30, 2008

Page 163 of 809

Under development Preliminary specification

Specifications in this manual are tentative and subject to change.

10. Power Control

R8C/L35A Group, R8C/L36A Group, R8C/L38A Group, R8C/L3AA Group,

R8C/L35B Group, R8C/L36B Group, R8C/L38B Group, R8C/L3AB Group

10.7

Reducing Power Consumption

This section describes key points and processing methods for reducing power consumption. They should be

referred to when designing a system or creating a program.

10.7.1

Voltage Detection Circuit

When voltage monitor 1 and comparator A1 are not used, set the VCA26 bit in the VCA2 register to 0 (voltage

detection 1 circuit disabled). When voltage monitor 2 and comparator A2 are not used, set the VCA27 bit in the

VCA2 register to 0 (voltage detection 2 circuit disabled).

When 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).

10.7.2

Ports

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, and 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.

10.7.3

Clocks

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.

Unnecessary clocks should be stopped accordingly.

Stopping the low-speed on-chip oscillator oscillation: CM14 bit in CM1 register

Stopping the high-speed on-chip oscillator oscillation: FRA00 bit in FRA0 register

10.7.4

Wait Mode, Stop Mode, and Power-Off Mode

Power consumption can be reduced in wait mode, stop mode, and power-off mode.

10.7.5

Stopping Peripheral Function Clocks

When peripheral function clocks are not necessary in wait mode, set bits CM01 and CM02 bit in the CM0

10.7.6

Timers

When timer RA is not used, set the TCKCUT bit in the TRAMR register to 1 (count source cutoff).

When timer RB is not used, set the TCKCUT bit in the TRBMR register to 1 (count source cutoff).

When timer RC is not used, set the MSTTRC bit in the MSTCR register to 1 (standby).

When timer RD is not used, set the MSTTRD bit in the MSTCR register to 1 (standby).

When timer RG is not used, set the MSTTRG bit in the MSTCR register to 1 (standby).

R5F2L3ACBNFP Datasheet(PDF) 199 Page - Renesas Technology Corp

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