
47
SINGLE-CHIP 8-BIT CMOS MICROCOMPUTER
MITSUBISHI MICROCOMPUTERS
3827 Group
Fig. 54 State transitions of system clock
Low-power dissipation
mode (f(
φ
) =16 kHz)
CM
7
=1(32 kHz selected)
CM
6
=0(High-speed)
CM
5
=1(8 MHz stopped)
CM
4
=1(32 kHz oscillating)
Notes 1 :
Switch the mode by the allows shown between the mode blocks. (Do not switch between the mode directly without an allow.)
The all modes can be switched to the stop mode or the wait mode and returned to the source mode when the stop mode or the wait mode is ended.
3 :
Timer and LCD operate in the wait mode.
4 :
When the stop mode is ended, wait time can be set by connecting timer 1 and timer 2 in middle-/high-speed mode.
5 :
When the stop mode is ended, wait time can be set by connecting timer 1 and timer 2 in low-speed mode.
6 :
Wait until oscillation stabilizes after oscillating the main clock X
IN
before the switching from the low-speed mode to middle-/high-speed mode.
7 :
The example assumes that 8 MHz is being applied to the X
IN
pin and 32 kHz to the X
CIN
pin.
φ
indicates the internal clock.
CM
4
: Port Xc switch bit
0: I/O port function
1: X
CIN
–X
COUT
oscillating function
CM
5
: Main clock (X
IN
–X
OUT
) stop bit
0: Oscillating
1: Stopped
CM
6
: Main clock division ratio selection bit
0: f(X
IN
)/2 (high-speed mode)
1: f(X
IN
)/8 (middle-speed mode)
CM
7
: Internal system clock selection bit
0: X
IN
–X
OUT
selected
(middle-/high-speed mode)
1: X
CIN
–X
COUT
selected
(low-speed mode)
CPU mode register
(CPUM : address 003B
16
)
b7
b4
Reset
CM
6
“1”
“0”
C
4
“
“
CM
7
=0(8 MHz selected)
CM
6
=1(Middle-speed)
CM
5
=0(8 MHz oscillating)
CM
4
=0(32 kHz stopped)
Middle-speed mode (f(
φ
) =1 MHz)
CM
7
=0(8 MHz selected)
CM
6
=1(Middle-speed)
CM
5
=0(8 MHz oscillating)
CM
4
=1(32 kHz oscillating)
Middle-speed mode (f(
φ
) =1 MHz)
CM
7
=0(8 MHz selected)
CM
6
=0(High-speed)
CM
5
=0(8 MHz oscillating)
CM
4
=0(32 kHz stopped)
High-speed mode (f(
φ
) =4 MHz)
CM
7
=0(8 MHz selected)
CM
6
=0(High-speed)
CM
5
=0(8 MHz oscillating)
CM
4
=1(32 kHz oscillating)
High-speed mode (f(
φ
) =4 MHz)
CM
7
=1(32 kHz selected)
CM
6
=1(Middle-speed)
CM
5
=0(8 MHz oscillating)
CM
4
=1(32 kHz oscillating)
Low-speed mode (f(
φ
) =16 kHz)
CM
7
=1(32 kHz selected)
CM
6
=0(High-speed)
CM
5
=0(8 MHz oscillating)
CM
4
=1(32 kHz oscillating)
Low-speed mode (f(
φ
) =16 kHz)
Low-power dissipation
mode (f(
φ
) =16 kHz)
CM
7
=1(32 kHz selected)
CM
6
=1(Middle-speed)
CM
5
=1(8 MHz stopped)
CM
4
=1(32 kHz oscillating)
CM
6
“1”
“0”
CM
6
“1”
“0”
CM
6
“1”
“0”
C
4
“
“
C
7
“
“
C
7
“
“
C
5
“
“
C
5
“
“
CM
4
“1
CM
6
“1
“0
“0
CM
4
CM
6
“0
“1
“1
“0
CM
5
“1
CM
6
“1
“0
“0
CM
5
CM
6
“0
“1
“1
“0