M32CSLASH86 datasheet(482/505 Pages) RENESAS

482 / 505 page

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27.5.6.3 Suggestions for Reducing Power Consumption

The followings are suggestions for reducing power consumption when programming or designing

systems.

Ports: I/O ports maintains the same state despite the microcomputer entering wait mode or stop

mode. Current flows through active output ports. Feedthrough current flows through input ports in a

high-impedance state. Set unassigned ports as input ports and stabilize electrical potential before

entering wait mode or stop mode.

A/D Converter: If the A/D conversion is not performed, set the VCUT bit in the AD0CON1 register

to "0" (no VREF connection). Set the VCUT bit to "1" (VREF connection) and wait at least 1

µs before

starting the A/D conversion.

D/A Converter: Set the DAi bit (i=0, 1) in the DACON register to "0" (output disabled) and set the

DAi register to "0016" when the D/A conversion is not performed.

Peripheral Function Stop: Set the CM02 bit in the CM0 register while in wait mode to stop unnec-

essary peripheral functions. However, this does not reduce power consumption because the pe-

ripheral function clock (fc32) generating from the sub clock does not stop. When in low-speed mode

and low-power consumption mode, do not enter wait mode when the CM02 bit is set to "1" (periph-

eral clock stops in wait mode).

27. Precautions (Clock Generation Circuit)

M32C/86 Datasheet(PDF) 482 Page - Renesas Technology Corp