Datasheet

M16C/6S Group Clock Generation Circuit
R01DS0201EJ0502 Rev.5.02 page 34 of 203
Dec 25, 2012
(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.