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M16C/62P Group (M16C/62P, M16C/62PT)
10.2 CPU Clock and Peripheral Function Clock
Two type clocks: CPU clock to operate the CPU and peripheral function clocks to operate the peripheral
functions.
10.2.1 CPU Clock and BCLK
These are operating clocks for the CPU and watchdog timer.
The clock source for the CPU clock can be chosen to be the main clock, sub clock, on-chip oscillator clock
or the PLL clock.
If the main clock or on-chip oscillator clock is selected as the clock source for the CPU clock, the selected
clock source can be divided by 1 (undivided), 2, 4, 8 or 16 to produce the CPU clock. Use the CM06 bit
in CM0 register and the CM17 to CM16 bits in the CM1 register to select the divide-by-n value.
When the PLL clock is selected as the clock source for the CPU clock, the CM06 bit should be set to "0"
and the CM17 to CM16 bits to "00b" (undivided).
After reset, the main clock divided by 8 provides the CPU clock.
During memory expansion or microprocessor mode, a BCLK signal with the same frequency as the CPU
clock can be output from the BCLK pin by setting the PM07 bit in the PM0 register to "0" (output enabled).
Note that when entering stop mode from high or middle speed mode, on-chip oscillator mode or on-chip
oscillator low power dissipation mode, or when the CM05 bit in the CM0 register is set to "1" (main clock
turned off) in low-speed mode, the CM06 bit in the CM0 register is set to "1" (divide-by-8 mode).
10.2.2 Peripheral Function Clock (f1, f2, f8, f32, f1SIO, f2SIO, f8SIO, f32SIO, fAD, fC32)
These are operating clocks for the peripheral functions.
Of these, fi (i = 1, 2, 8, 32) and fiSIO are derived from the main clock, PLL clock or on-chip oscillator clock
by dividing them by i. The clock fi is used for timers A and B, and fiSIO is used for serial I/O. The f8 and
f32 clocks can be output from the CLKOUT pin.
The fAD clock is produced from the main clock, PLL clock or on-chip oscillator clock, and is used for the
A/D converter.
When the WAIT instruction is executed after setting the CM02 bit in the CM0 register to "1" (peripheral
function clock turned off during wait mode), or when the microcomputer is in low power dissipation mode,
the fi, fiSIO and fAD clocks are turned off.
The fC32 clock is produced from the sub clock, and is used for timers A and B. This clock can be used
when the sub clock is on.
10.3 Clock Output Function
During single-chip mode, the f8, f32 or fC clock can be output from the CLKOUT pin. Use the CM01 to
CM00 bits in the CM0 register to select.
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10. Clock Generating Circuit
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