Clock Generation Circuit
69
Mitsubishi microcomputers
M16C / 62P Group
SINGLE-CHIP 16-BIT CMOS MICROCOMPUTER
development
Preliminary Specifications Rev.1.0
Specifications in this manual are tentative and subject to change.
Figure 1.9.11. State Transition in Normal Mode
CM04=0
CPU clock: f(PLL)
CM07=0
CM06=0
CM17=0
CM16=0
PLL operation mode
CM07=0
CM06=0
CM17=0
CM16=0
CM07=0
CM06=0
CM17=0
CM16=0
CM07=0
CM06=0
CM17=0
CM16=1
CM07=0
CM06=0
CM17=1
CM16=0
CM07=0
CM06=1
CM07=0
CM06=0
CM17=1
CM16=1
High-speed mode
CM07=0
CM06=0
CM17=0
CM16=0
CM07=0
CM06=0
CM17=0
CM16=1
CM07=0
CM06=0
CM17=1
CM16=0
CM07=0
CM06=1
CM07=0
CM06=0
CM17=1
CM16=1
CM07=0
Low-speed mode
CM07=0
CM06=1
CM15=1
Low power dissipation mode
Ring oscillator mode
CPU clock
f(Ring)
f(Ring)/2
f(Ring)/4
f(Ring)/8
f(Ring)/16
Ring oscillator
mode
CPU clock
f(Ring)
f(Ring)/8
f(Ring)/16
CPU clock
f(Ring)
f(Ring)/2
f(Ring)/4
f(Ring)/8
f(Ring)/16
Ring oscillator
low power
dissipation mode
CPU clock
f(Ring)
f(Ring)/8
f(Ring)/16
CM07=0
Low-speed mode
CM07=0
CM06=1
CM15=1
Low power
dissipation mode
PLC07=1
CM11=1
(Note 6)
PLC07=0
CM11=0
(Note 7)
CM04=0
PLC07=1
CM11=1
(Note 6)
PLC07=0
CM11=0
(Note 7)
CM04=0
CM04=1
CM04=1
CM04=1
CM04=0
CM04=1
(CM07=0
CM07=1
(Note 3)
CM05=1
(Note 1)
CM05=0
CM05=0
CM05=1
(Note 1)
CM21=0
(Note 8)
CM21=1
CM21=0
(Note 8)
CM21=1
CM21=0
CM21=1
CM21=0
CM21=1
Main clock oscillation
Ring oscillator clock
oscillation
Ring oscillator low power
dissipation mode
Sub clock oscillation
PLL operation
mode
CPU clock: f(PLL)
CPU clock: f(X
IN
)
High-speed mode
Middle-speed mode
(divide by 2)
CPU clock: f(X
IN
)/2
CPU clock: f(X
IN
)/4
CPU clock: f(X
IN
)/8
CPU clock: f(X
IN
)/16
CPU clock: f(X
CIN
)
CPU clock: f(X
CIN
)
CPU clock: f(X
CIN
)
CPU clock: f(X
CIN
)
CM05=0
C(Note 1)
CM05=1
(Note 1)
CM05=0
Middle-speed mode
(divide by 4)
Middle-speed mode
(divide by 8)
Middle-speed mode
(divide by 16)
Middle-speed mode
(divide by 2)
Middle-speed mode
(divide by 4)
Middle-speed mode
(divide by 8)
Middle-speed mode
(divide by 16)
CPU clock: f(X
IN
)
CPU clock: f(X
IN
)/2
CPU clock: f(X
IN
)/4
CPU clock: f(X
IN
)/8
CPU clock: f(X
IN
)/16
Notes:
1: Avoid making a transition when the CM20 bit is set to “1” (oscillation stop, re-oscillation detection function enabled).
Set the CM20 bit to “0” (oscillation stop, re-oscillation detection function disabled) before transiting.
2: Switch clock after oscillation of main clock is sufficiently stable.
3: Switch clock after oscillation of sub-clock is sufficiently stable.
4: Change CM17 and CM16 before changing CM06.
5: Transit in accordance with arrow.
6: PLL operation mode can only be entered from high speed mode. Also, wait until the PLL clock is sufficiently stable before changing operation modes.
To select a 16 MHz or higher PLL clock, set the PM20 bit to “0” (SFR accessed with two wait states) before setting PLC07 to “1” (PLL operation).
7: PLL operation mode can only be changed to high speed mode. If the PM20 bit = 0 (SFR accessed with two wait states), set PLC07 to “0” (PLL turned off)
before setting the PM20 bit to “1” (SFR accessed with one wait state).
8: Set the CM06 bit to “1” (division by 8 mode) before changing back the operation mode from ring oscillator mode to high- or middle-speed mode.