
8. Clock Generation Circuits
8.5.2
Single-Speed Mode
8.5.2.1
Main Clock Mode
The main clock divided by 1 (no division), 2, 3, 4, 6, 8, 10, 12, 14, or 16 is used as the source for the CPU clock.
The main clock is also used for fPFC. When the sub clock is running, fC32 can be used as the count source for
timer A and timer B.
8.5.2.2
PLL Single-Speed Mode
The PLL clock divided by 2, 3, 4, 6, 8, 10, 12, 14, or 16 is used as the source for the CPU clock. The PLL clock
is also used for fPFC. When the sub clock is running, fC32 can be used as the count source for timer A and
timer B.
8.5.2.3
Low-Speed Mode
The sub clock is used as the source for the CPU clock. The main clock, PLL clock, or on-chip oscillator clock is
used as the source for the fPFC. fC32 can be used as the count source for timer A and timer B.
8.5.2.4
Low-Power Consumption Mode
The MCU enters low-power consumption mode when the main clock stops in low-speed mode. The sub clock is
used as the source for the CPU clock. fC32 can be used as the count source for timer A and timer B. In low-
power consumption mode, bits MCD4 to MCD0 in the MCD register become 01000b (divide-by-8 mode).
Therefore, next time the CPU clock source is switched to the main clock, the CPU clock is the main clock
divided by 8.
8.5.2.5
On-Chip Oscillator Mode
The on-chip oscillator clock divided by 1 (no division), 2, 3, 4, 6, 8, 10, 12, 14, or 16 is used as the source for
the CPU clock. The on-chip oscillator clock is also used for fPFC. When the sub clock is running, fC32 can be
used as the count source for timer A and timer B.
8.5.2.6
On-Chip Oscillator Low-power Consumption Mode
The MCU enters on-chip oscillator low-power consumption mode when the main clock stops in on-chip
oscillator mode. The on-chip oscillator clock divided by 1 (no division), 2, 3, 4, 6, 8, 10, 12, 14, or 16 is used as
the source for the CPU clock. The on-chip oscillator clock is also used for fPFC. When the sub clock is running,
fC32 can be used as the count source for timer A and timer B.
When switching the CPU clock source, wait until the next source clock stabilizes.
To switch the CPU clock source from the on-chip oscillator clock to the main clock, set bits MCD4 to MCD0 in
the MCD register to 01000b (divide-by-8 mode) in on-chip oscillator mode. Do not enter on-chip oscillator
mode or on-chip oscillator low-power consumption mode from low-speed mode or low-power consumption
mode and vice versa.