3820 GROUP USER’S MANUAL
1-44
MITSUBISHI MICROCOMPUTERS
3820 Group
SINGLE-CHIP 8-BIT CMOS MICROCOMPUTER
Fig. 45 State transitions of internal clock
φ
CM
4
: Port Xc switch bit
0: I/O port
1: X
CIN
, X
COUT
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)
Note
Reset
C
4
C
7
C
4
C
5
CM
6
"1"
CM
6
"1"
CPU mode register
(CPUM : address 003B
16
)
7
4
C
7
C
5
CM
6
"1"
CM
6
"1"
"0"
"
"
"
"
"
"
"
"
"
"
"
"
"0"
"0"
"0"
CM
4
CM
6
"1
"0
"0
"1
CM
4
"1
CM
6
"1
"0
"0
CM
5
CM
6
"1
"0
"0
"1
CM
5
"1
CM
6
"1
"0
"0
CM
7
=0(8MHz selected)
CM
6
=1(Middle-speed)
CM
5
=0(8MHz oscillating)
CM
4
=0(32kHz stopped)
CM
7
=0(8MHz selected)
CM
6
=0(High-speed)
CM
5
=0(8MHz oscillating)
CM
4
=0(32kHz stopped)
CM
7
=0(8MHz selected)
CM
6
=0(High-speed)
CM
5
=0(8MHz oscillating)
CM
4
=1(32kHz oscillating)
CM
7
=1(32kHz selected)
CM
6
=0(High-speed)
CM
5
=0(8MHz oscillating)
CM
4
=1(32kHz oscillating)
CM
7
=1(32kHz selected)
CM
6
=0(High-speed)
CM
5
=1(8MHz stopped)
CM
4
=1(32kHz oscillating)
CM
7
=0(8MHz selected)
CM
6
=1(Middle-speed)
CM
5
=0(8MHz oscillating)
CM
4
=1(32kHz oscillating)
CM
7
=1(32kHz selected)
CM
6
=1(Middle-speed)
CM
5
=0(8MHz oscillating)
CM
4
=1(32kHz oscillating)
CM
7
=1(32kHz selected)
CM
6
=1(Middle-speed)
CM
5
=1(8MHz stopped)
CM
4
=1(32kHz oscillating)
Low-speed mode (f(
φ
) =16 kHz)
Low-speed mode (f(
φ
) =16 kHz)
Low-speed mode (f(
φ
) =16 kHz)
Low-speed mode (f(
φ
) =16 kHz)
High-speed mode (f(
φ
) =4MHz)
Middle-speed mode
(f(
φ
) =1 MHz)
Middle-speed mode
(f(
φ
) =1 MHz)
High-speed mode (f(
φ
) =4MHz)
1:Switch the mode by the allows shown between the mode blocks. (Do not switch between the mode directly without an allow.)
2: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 released.
3:Timer and LCD operate in the wait mode.
4:In middle-/high-speed mode, when the stop mode is released, a delay of approximately 1 ms occurs automatically by timer 1 and
timer 2.
5:In low-speed mode, when the stop mode is released, a delay of approximately 0.25 s occurs automatically by timer 1 and timer 2.
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.