1-68
3874 Group User’s Manual
HARDWARE
FUNCTIONAL DESCRIPTION
Fig. 73 State transitions of system clock
“0”
←→
“1”
Reset
Notes 1: Switch the mode by the arrows shown between the mode blocks. (Do not switch between the modes directly without an arrow.)
2: 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.
3: Timer operates in the wait mode.
4: When the stop mode is ended, wait time is generated automatically by connecting timer 1 and timer 2.
5: The example assumes that 6.3 MHz is being applied to the X IN pin and 32 kHz to the X CIN pin.
φ indicates the internal clock.
6: We recommend that X COUT drivability selection bit is set to “1” (high) because reliance of oscillation stability is improved.
High-speed mode
(
φ=3.15 MHz)
CM7=0
High-speed mode
CM6=0
6.3 MHz selected
CM5=0 (XIN oscillating)
CM4=0 (32 kHz stopped)
CM3=1 (XCOUT drivability
High)
Middle-speed mode
(
φ=788 kHz)
CM7=0 Middle-speed mode
CM6=1 6.3 MHz selected
CM5=0 (XIN oscillating)
CM4=0 (32 kHz stopped)
CM3=1 (XCOUT drivability
High)
Double-speed mode
(
φ=6.3 MHz)
CM7=1 Double-speed mode
CM6=1 6.3 MHz selected
CM5=0 (XIN oscillating)
CM4=0 (32 kHz stopped)
CM3=1 (XCOUT drivability
High)
Middle-speed mode
(
φ=788 kHz)
CM7=0 Middle-speed mode
CM6=1 6.3 MHz selected
CM5=0 (XIN oscillating)
CM4=1 (32 kHz oscillating)
CM3=1 (XCOUT drivability
High)
Double-speed mode
(
φ=6.3 MHz)
CM7=1 Double-speed mode
CM6=1 6.3 MHz selected
CM5=0 (XIN oscillating)
CM4=1 (32 kHz oscillating)
CM3=1 (XCOUT drivability
High)
High-speed mode
(
φ=3.15 MHz)
CM7=0
High-speed mode
CM6=0
6.3 MHz selected
CM5=0 (XIN oscillating)
CM4=1 (32 kHz oscillating)
CM3=1 (XCOUT drivability
High)
Low-speed mode (
φ=16 kHz)
CM7=1
Low-speed mode
CM6=0
32 kHz selected
CM5=0 (XIN oscillating)
CM4=1 (32 kHz oscillating)
CM3=0 (XCOUT drivability
Low)
Low-speed mode (
φ=16 kHz)
CM7=1
Low-speed mode
CM6=0
32 kHz selected
CM5=0 (XIN oscillating)
CM4=1 (32 kHz oscillating)
CM3=1 (XCOUT drivability
High)
Low-speed mode (
φ=16 kHz)
CM7=1
Low consumption
mode
CM6=0
32 kHz selected
CM5=1 (XIN stopped)
CM4=1 (32 kHz oscillating)
CM3=0 (XCOUT drivability
Low)
CM3 : XCOUT drivability selection bit
0 : Low
1 : High
CM4 : Port Xc switch bit
0 : I/O port function
1 : XCIN-XCOUT oscillating function
CM5 : Main clock (XIN- XOUT) stop bit
0 : Oscillating
1 : Stopped
CM7,CM6 : Main clock division ratio selection bits
CM7 CM6
0
0 :
φ=f(XIN)/2 (high-speed mode)
0
1 :
φ=f(XIN)/8 (middle-speed mode)
1
0 :
φ=f(XCIN)/2 (low-speed mode)
1
1 :
φ=f(XIN)
(double-speed mode)
CPU mode register
(CPUM: address 003B 16)
CM
3
“0”
←→
“1”
CM
5
“0”
←→
“1”
CM
5
“1”
←→
“0”
CM3
“0”
←→“1”
CM
6
“0”
←
“1”
“0”
←→
“1”
CM
7
“1”
←→
“0”
←→“1”
CM7
“0”
←→“1”
CM7
“0”
←→“1”
CM6
“0”
←→“1”
“0”
←→
“1”
CM
7
“1”
←→
“0”
CM
7
“0”
←→
“1”
“0”
←→
“1”
CM
7
“1”
←→
“0”
←→
“1”
CM
4
“1”
←→
“0”
CM
7
“0”
←→
“1”
CM
7
CM
4
“0”
←→
“1”
CM
4
“1”
←→
“0”
CM
4
“1”
←→
“0”
CM
4
“1”
←→
“0”
CM7
“0”
←→“1”
CM6
“0”
←→“1”
“0”
←→“1”
CM7
“0”
←→“1”
CM
4
“1”
←→
“0”
CM
0
“0”
←→
“1”
“0”
←→
“1”
CM
6
CM
4
“0”
←→
“1”
b7
b0
CM6
CM
6
CM
3
CM
6
CM
3