R8C2K datasheet(103/471 Pages) RENESAS

103 / 471 page

R8C/2K Group, R8C/2L Group

10. Clock Generation Circuit

Rev.1.10

Dec 21, 2007

Page 86 of 450

REJ09B0406-0110

10.4.2

Wait Mode

Since the CPU clock stops in wait mode, the CPU, which operates using the CPU clock, and the watchdog

timer, when count source protection mode is disabled, stop. The XIN clock and on-chip oscillator clock do not

stop and the peripheral functions using these clocks continue operating.

10.4.2.1

Peripheral Function Clock Stop Function

If the CM02 bit is set to 1 (peripheral function clock stops in wait mode), the f1, f2, f4, f8, and f32 clocks stop

in wait mode. This reduces power consumption.

10.4.2.2

Entering Wait Mode

The MCU enters wait mode when the WAIT instruction is executed.

When the OCD2 bit in the OCD register is set to 1 (on-chip oscillator selected as system clock), set the OCD1

bit in the OCD register to 0 (oscillation stop detection interrupt disabled) before executing the WAIT

instruction.

If the MCU enters wait mode while the OCD1 bit is set to 1 (oscillation stop detection interrupt enabled),

current consumption is not reduced because the CPU clock does not stop.

10.4.2.3

Pin Status in Wait Mode

The I/O port is the status before wait mode was entered is maintained.

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