R27 datasheet(115/487 Pages) RENESAS

115 / 487 page

R8C/26 Group, R8C/27 Group

10. Clock Generation Circuit

Rev.2.10

Sep 26, 2008

Page 96 of 453

REJ09B0278-0210

10.5.2

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, XCIN clock, and on-chip oscillator

clock do not stop and the peripheral functions using these clocks continue operating.

10.5.2.1

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.

10.5.2.2

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.

10.5.2.3

Pin Status in Wait Mode

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

R27 Datasheet(PDF) 115 Page - Renesas Technology Corp