Renesas R8C/Tiny Series Manual descargar pdf (Pagina 34)

R8C/10 Group

Rev.1.20 Jan 27, 2006 page 24 of 180

REJ09B0019-0120

CM06 CM05

010

110

00 or 1

6.4 Power Control

There are three power control modes. All modes other than wait and stop modes are referred to as

normal operation mode.

6.4.1 Normal Operation Mode

Normal operation mode is further classified into three modes.

In normal operation mode, because the CPU clock and the peripheral function clocks both are on, the

CPU and the peripheral functions are operating. Power control is exercised by controlling the CPU

clock frequency. The higher the CPU clock frequency, the greater the processing capability. The lower

the CPU clock frequency, the smaller the power consumption in the chip. If the unnecessary oscillator

circuits are turned off, the power consumption is further reduced.

Before the clock sources for the CPU clock can be switched over, the new clock source to which

switched must be oscillating stably. If the new clock source is the main clock, allow a sufficient wait

time in a program until it becomes oscillating stably.

• High-speed Mode

The main clock divided by 1 undivided provides the CPU clock. If the CM14 bit is set to “0” (on-chip

oscillator on), the f

RING is used as the count source for timer Y.

• 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” (on-chip

oscillator on), the fRING is used as the count source for timer Y.

• On-Chip Oscillator Mode

The on-chip oscillator clock divided by 1 (undivided), 2, 4, 8 or 16 provides the CPU clock. The on-

chip oscillator clock is also the clock source for the peripheral function clocks.

6.4 Power Control

Table 6.2 Setting Clock Related Bit and Modes

1 2 ... 29 30 31 32 33 34 35 36 37 38 39 ... 198 199

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Renesas R8C/Tiny Series Manual Pagina 34