Mitsubishi microcomputers
M16C / 62P Group
SINGLE-CHIP 16-BIT CMOS MICROCOMPUTER
Clock Generation Circuit
62
development
Preliminary Specifications Rev.1.0
Specifications in this manual are tentative and subject to change.
CPU Clock and Peripheral Function Clock
Two type clocks: CPU clock to operate the CPU and peripheral function clocks to operate the peripheral
functions.
(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, ring oscillator clock or
the PLL clock.
If the main clock or ring 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 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 “00
2
” (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 of PM0 register to “0” (output enabled).
Note that when entering stop mode from high or middle speed mode, ring oscillator mode or low power
ring oscillator mode, or when the CM05 bit of CM0 register is set to “1” (main clock turned off) in low-
speed mode, the CM06 bit of CM0 register is set to “1” (divide-by-8 mode).
(2) Peripheral Function Clock(f
1
, f
2
, f
8
, f
32
, f
1SIO
, f
2SIO
, f
8SIO
, f
32SIO
, f
AD
, f
C32
)
These are operating clocks for the peripheral functions.
Of these, fi (i = 1, 2, 8, 32) and fi
SIO
are derived from the main clock, PLL clock or ring oscillator clock by
dividing them by i. The clock fi is used for timers A and B, and fi
SIO
is used for serial I/O. The f
8
and f
32
clocks can be output from the CLK
OUT
pin.
The f
AD
clock is produced from the main clock, PLL clock or ring oscillator clock, and is used for the A-D
converter.
When the WAIT instruction is executed after setting the CM02 bit of CM0 register to “1” (peripheral
function clock turned off during wait mode), or when the microcomputer is in low power dissipation mode,
the fi, fi
SIO
and f
AD
clocks are turned off.
The f
C32
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.
Clock Output Function
During single-chip mode, the f
8
, f
32
or f
C
clock can be output from the CLK
OUT
pin. Use the CM01 to
CM00 bits of CM0 register to select.