49
3819 Group
SINGLE-CHIP 8-BIT CMOS MICROCOMPUTER
MITSUBISHI MICROCOMPUTERS
Fig. WA-4 State transitions of system clock
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 return to the source mode when the stop mode or the wait mode
is ended.
Timer operates in the wait mode.
When the stop mode is released in middle/high-speed mode, a delay of approximately 0.5 ms occurs automatically by timer 1.
When the stop mode is released in low-speed mode, a delay of approximately 0.125 s occurs automatically by timer 1.
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.
Low power dissipation mode (
φ
=16 kHz)
CM
7
= 1 (32 kHz selected)
CM
6
= 0 (High-speed)
CM
5
= 1 (X
IN
stopped)
CM
4
= 1 (32 kHz oscillating)
“1 CM
4
“0 CM
b7
CPU mode register
(CPUM (CM) : address 003B
16
)
CM
4
: Port X
C
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)
b0
Notes 1 :
2 :
3 :
4 :
5 :
Reset
6
CM
4
“CM
C
4
“
CM
6
“1” “0”
C
4
“
C
7
“
CM
6
“1” “0”
C
7
“
C
5
“
CM
6
“1” “0”
C
5
“
High-speed mode (
φ
= 4 MHz)
CM
7
= 0 (8 MHz selected)
CM
6
= 0 (High-speed)
CM
5
= 0 (X
IN
oscillating)
CM
4
= 1 (32 kHz oscillating)
CM
6
“1” “0”
Middle-speed mode (
φ
=1 MHz)
CM
7
= 0 (8 MHz selected)
CM
6
= 1 (Middle-speed)
CM
5
= 0 (X
IN
oscillating)
CM
4
= 1 (32 kHz oscillating)
Middle-speed mode (
φ
=1 MHz)
CM
7
= 0 (8 MHz selected)
CM
6
= 1 (Middle-speed)
CM
5
= 0 (X
IN
oscillating)
CM
4
= 0 (32 kHz stopped)
High-speed mode (
φ
= 4 MHz)
CM
7
= 0 (8 MHz selected)
CM
6
= 0 (High-speed)
CM
5
= 0 (X
IN
oscillating)
CM
4
= 0 (32 kHz stopped)
Low-speed mode (
φ
=16 kHz)
CM
7
= 1 (32 kHz selected)
CM
6
= 1 (Middle-speed)
CM
5
= 0 (X
IN
oscillating)
CM
4
= 1 (32 kHz oscillating)
Low-speed mode (
φ
= 16 kHz)
CM
7
= 1 (32 kHz selected)
CM
6
= 0 (High-speed)
CM
5
= 0 (X
IN
oscillating)
CM
4
= 1 (32 kHz oscillating)
Low power dissipation mode (
φ
=16 kHz)
CM
7
= 1 (32 kHz selected)
CM
6
= 1 (Middle-speed)
CM
5
= 1 (X
IN
stopped)
CM
4
= 1 (32 kHz oscillating)
“1 CM
5
“0 CM
6
CM
5
CM