Wait Mode - Renesas R8C Series User Manual

R8C/1A Group, R8C/1B Group
10.4.1.1 High-Speed Mode
The main clock divided by 1 (no division) provides the CPU clock. If the CM14 bit is set to 0 (low-speed on-
chip oscillator on) or the HRA00 bit in the HRA0 register is set to 1 (high-speed on-chip oscillator on), fRING
and fRING128 can be used as timers X and C. When the HRA00 bit is set to 1, fRING-fast can be used as timer
C. When the CM14 bit is set to 0 (low-speed on-chip oscillator on), fRING-S can be used for the watchdog
timer and voltage detection circuit.
10.4.1.2 Medium-Speed Mode
The main clock divided by 2, 4, 8, or 16 provides the CPU clock. If the CM14 bit is set to 0 (low-speed on-chip
oscillator on) or the HRA00 bit in the HRA0 register is set to 1 (high-speed on-chip oscillator on), fRING and
fRING128 can be used as timers X and C. When the HRA00 bit is set to 1, fRING-fast can be used as timer C.
When the CM14 bit is set to 0 (low-speed on-chip oscillator on), fRING-S can be used for the watchdog timer
and voltage detection circuit.
10.4.1.3 High-Speed and Low-Speed On-Chip Oscillator Modes
The on-chip oscillator clock divided by 1 (no division), 2, 4, 8, or 16 provides the CPU clock. The on-chip
oscillator clock is also the clock source for the peripheral function clocks. When the HRA00 bit is set to 1,
fRING-fast can be used as timer C. When the CM14 bit is set to 0 (low-speed on-chip oscillator on), fRING-S
can be used for the watchdog timer and voltage detection circuit.
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 main 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.
10.4.2.3 Pin Status in Wait Mode
The status before wait mode was entered is maintained.
Rev.1.30 Dec 08, 2006
REJ09B0252-0130
Page 69 of 315
10. Clock Generation Circuit