MITSUBISHI MICROCOMPUTERS
3827 Group
SINGLE-CHIP 8-BIT CMOS MICROCOMPUTER
Reset
CM
“1”
6
Middle-speed mode (f(φ) =1 MHz)
High-speed mode (f(φ) =4 MHz)
“0”
CM
CM
CM
CM
7
6
5
4
=0(8 MHz selected)
=1(Middle-speed)
=0(8 MHz oscillating)
=0(32 kHz stopped)
CM7=0(8 MHz selected)
CM6=0(High-speed)
CM5=0(8 MHz oscillating)
CM4=0(32 kHz stopped)
“0”
4
CM
“1”
“0”
6
CM
“1”
CM
“1”
6
Middle-speed mode (f(φ) =1 MHz)
High-speed mode (f(φ) =4 MHz)
“0”
CM7=0(8 MHz selected)
CM6=1(Middle-speed)
CM7=0(8 MHz selected)
CM6=0(High-speed)
CM5=0(8 MHz oscillating)
CM4=1(32 kHz oscillating)
CM5=0(8 MHz oscillating)
CM4=1(32 kHz oscillating)
CM
“1”
6
Low-speed mode (f(φ) =16 kHz)
Low-speed mode (f(φ) =16 kHz)
“0”
CM7=1(32 kHz selected)
CM6=1(Middle-speed)
CM7=1(32 kHz selected)
CM6=0(High-speed)
b7
b4
CM5=0(8 MHz oscillating)
CM4=1(32 kHz oscillating)
CM5=0(8 MHz oscillating)
CM4=1(32 kHz oscillating)
CPU mode register
(CPUM : address 003B16
)
CM
CM
CM
CM
4
: Port Xc switch bit
0: I/O port function
1: XCIN–XCOUT oscillating function
: Main clock (XIN–XOUT) stop bit
“0”
5
CM
“0”
6
“1”
5
CM
“1”
0: Oscillating
1: Stopped
6
: Main clock division ratio selection bit
Low-power dissipation
mode (f(φ) =16 kHz)
Low-power dissipation
mode (f(φ) =16 kHz)
CM
“1”
6
0: f(XIN)/2 (high-speed mode)
1: f(XIN)/8 (middle-speed mode)
“0”
CM7=1(32 kHz selected)
CM6=1(Middle-speed)
CM5=1(8 MHz stopped)
CM4=1(32 kHz oscillating)
CM
CM
CM
CM
7
=1(32 kHz selected)
7
: Internal system clock selection bit
6=0(High-speed)
5=1(8 MHz stopped)
0: XIN–XOUT selected
(middle-/high-speed mode)
1: XCIN–XCOUT selected
(low-speed mode)
4=1(32 kHz oscillating)
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 ended.
3 : Timer and LCD operate in the wait mode.
Notes
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 XIN pin and 32 kHz to the XCIN pin. φ indicates the internal clock.
Fig. 54 State transitions of system clock
47
MITSUBISHI [ Mitsubishi Group ]
