M306H2MC-XXXFP Datasheet, PDF (39/210 Pages) Renesas Technology Corp – SINGLE-CHIP 16-BIT CMOS MICROCOMPUTER with DATA ACQUISITION CONTROLLER

MITSUBISHI MICROCOMPUTERS
M306H2MC-XXXFP
SINGLE-CHIP 16-BIT CMOS MICROCOMPUTER
with DATA ACQUISITION CONTROLLER
2.5.7 Power control
The following is a description of the three available power control modes:
Modes
Power control is available in three modes.
(a) Normal operation mode
• High-speed mode
Divide-by-1 frequency of the main clock becomes the BCLK. The CPU operates with the internal
clock selected. Each peripheral function operates according to its assigned clock.
• Medium-speed mode
Divide-by-2, divide-by-4, divide-by-8, or divide-by-16 frequency of the main clock becomes the
BCLK. The CPU operates according to the internal clock selected. Each peripheral function operates
according to its assigned clock.
• Low-speed mode
fC becomes the BCLK. The CPU operates according to the fc clock. The fc clock is supplied by the
secondary clock. Each peripheral function operates according to its assigned clock.
• Low power dissipation mode
The main clock operating in low-speed mode is stopped. The CPU operates according to the fC
clock. The fc clock is supplied by the secondary clock. The only peripheral functions that operate are
those with the sub-clock selected as the count source.
When in single-chip mode, the device can be operated with a low supply voltage (VCC = 3.0 V) only
during low power dissipation mode. Before entering or exiting low power dissipation mode, always
make sure the supply voltage VCC is 5 V.
Note: When operating with a low supply voltage, be aware that only the CPU, ROM, RAM, input/
output ports, timers (timers A and B), and the interrupt control circuit can be used. All other
internal resources (e.g., data slicer, DMAC, A/D, and D/A) cannot be used.
(b) Wait mode
The CPU operation is stopped. The oscillators do not stop.
(c) Stop mode
The main clock and the sub-clock oscillators stop. The CPU and all built-in peripheral functions stop.
This mode, among the three modes listed here, is the most effective in decreasing power consumption.
Figure 2.5.5 is the state transition diagram of the above modes.
Rev. 1.0
38