Renesas M16C/6NK Manual De Usuario

Rev.1.10    Jul 01, 2005    page 52 of 318
REJ09B0124-0110

M16C/6N Group (M16C/6NK, M16C/6NM)

7. Clock Generating Circuit

This document is under development and its contents are subject to change.

In stop mode, all oscillator circuits are turned off, so are the CPU clock and the peripheral function clocks.

Therefore, the CPU and the peripheral functions clocked by these clocks stop operating. The least

amount of power is consumed in this mode. If the voltage applied to VCC is VRAM or more, the internal

RAM is retained.

However, the peripheral functions clocked by external signals keep operating. The following interrupts

can be used to exit stop mode.

______

• NMI interrupt

• Key  interrupt

______

• INT interrupt

• Timer A, Timer B interrupt (when counting external pulses in event counter mode)

• Serial I/O interrupt (when external clock is selected)

• CAN0/1 Wake-up interrupt (when CAN sleep mode is selected)

The microcomputer is placed into stop mode by setting the CM10 bit in the CM1 register to “1” (all clocks

turned off). At the same time, the CM06 bit in the CM0 register is set to “1” (divide-by-8 mode) and the

CM15 bit in the CM1 register is set to “1” (main clock oscillator circuit drive capability high).

Before entering stop mode, set the CM20 bit in the CM2 register to “0” (oscillation stop, re-oscillation

detection function disabled).

Also, if the CM11 bit in the CM1 register is “1” (PLL clock for the CPU clock source), set the CM11 bit to

“0” (main clock for the CPU clock source) and the PLC07 bit in the PLC0 register to “0” (PLL turned off)

before entering stop mode.

Table 7.6 lists the pin status in stop mode.

Pin

Single-Chip Mode

I/O Ports

Retains status before stop mode

CLKOUT

“H”

Retains status before stop mode

When fC selected

When f8, f32 selected