M16C6S_09 Datasheet, PDF (34/208 Pages) Renesas Technology Corp – SINGLE-CHIP 16-BIT CMOS MICROCOMPUTER

M16C/6S Group
Clock Generation Circuit
(3) On-chip Oscillator Clock
This clock, approximately 1 MHz, is supplied by a On-chip Oscillator. This clock is used as the clock
source for the CPU and peripheral function clocks. In addition, if the PM22 bit of PM2 register is “1” (On-
chip Oscillator clock for the watchdog timer count source), this clock is used as the count source for the
watchdog timer.
After reset, the On-chip Oscillator clock is turned off. It is turned on by setting the CM21 bit of CM2
register to “1” (On-chip Oscillator clock), and is used as the clock source for the CPU and peripheral
function clocks, in place of the main clock.
Rev.5.01 Dec 10, 2009 page 34 of 201
REJ03B0014-0501