M32C8A Datasheet, PDF (353/372 Pages) Renesas Technology Corp – RENESAS MCU M16C FAMILY / M32C/80 Series

M32C/8A Group
24. Usage Notes
24.3.4.3 Suggestions to Reduce Power Consumption
The followings are suggestions to reduce power consumption when programming or designing systems.
Ports:
• Through current may flow into floating input pins. Set unassigned pins to input mode and connect them to
VSS via a resistor (pull down), or set unassigned pins to output mode and leave them open.
A/D converter:
• When the A/D conversion is not performed, set the VCUT bit in the AD0CON1 register to 0 (VREF not
connected). When the A/D conversion is performed, set the VCUT bit to 1 (VREF connection) and wait
1 μs or longer to start the A/D conversion.
D/A converter:
• When the D/A conversion is not performed, set the DAiE bit (i = 0, 1) in the DACON register to 0 (output
disabled) and the DAi register to 00h.
Peripheral function clock stop:
• When entering wait mode from main clock mode, on-chip oscillator mode, or on-chip oscillator low-power
consumption mode, power consumption can be reduced by setting the CM02 bit in the CM0 register to 1 to
stop peripheral function clock source (fPFC). However, fC32 does not stop by setting the CM02 bit to 1.
• In low-speed mode, do not set the CM02 bit to 1 (peripheral clock stops in wait mode) when entering wait
mode.
(Technical update: TN-M16C-69-0104)
Rev.1.00 Jul 15, 2007 Page 336 of 352
REJ09B0385-0100