Power control provides an effective means for reducing the power consumption in the MCU.
The M16C family microcomputers incorporate two clock generating circuits (Main Clock and Sub Clock). Power control is realized by switching between these clock circuits.

1. Selecting Oscillation Mode (Power Control Mode)
There are following three modes:
• Normal Operation Mode
• Wait Mode
• Stop Mode

2. Selecting the Operating Clock Source
The M16C family microcomputers have various operating clock sources to choose from, and this is the reason why their power consumption can be reduced whenever necessary. Namely, the operating clock for the CPU (i.e., BCLK) can be selected from the Main Clock not divided or divided by 2, 4, 8 or 16 or the Sub Clock (fc).

3. Setting the System Clock Control Registers 0 and 1
To control oscillation mode (power control mode), set by the System Clock Control Register 0 (address 00006) and System Clock Control Register 1 (address 00007). These two registers are protected by the Protect Register (address 0000A).