Under
development
Tentative Specifications REV.E1
Specifications in this manual are tentative and subject to change.
Mitsubishi microcomputers
M30100/M30102 Group
SINGLE-CHIP 16-BIT CMOS MICROCOMPUTER
22
System clock control register 0 (Note 1)
Symbol
Address
When reset
CM0
000616
4816
Bit name
Function
Bit symbol
b7
b6
b5
b4 b3
b2
b1
b0
CM07
CM05
CM04
CM03
CM02
CM06
Reserved bit
WAIT peripheral function
clock stop bit
0 : Do not stop peripheral function clock in wait mode
1 : Stop peripheral function clock in wait mode (Note 8)
XCIN-XCOUT drive capacity
select bit (Note 2)
0 : LOW
1 : HIGH
Port XC select bit
0 : I/O port
1 : XCIN-XCOUT generation
Main clock (XIN-XOUT)
stop bit (Note 3,4,5)
0 : On
1 : Off
Main clock division select
bit 0 (Note 7)
0 : CM16 and CM17 valid
1 : Division by 8 mode
System clock select bit
(Note 6)
0 : XIN, XOUT
1 : XCIN, XCOUT
Note 1: Set bit 0 of the protect register (address 000A16) to “1” before writing to this register.
Note 2: Changes to “1” when shifting to stop mode.
Note 3: This bit is used to stop the main clock when placing the device in a low-power mode. If you want to operate with XIN
after exiting from the stop mode, set this bit to “0”. When operating with a self-excited oscillator, set the system clock
select bit (CM07) to “1” before setting this bit to “1”.
Note 4: When inputting external clock, only clock oscillation buffer is stopped and clock input is acceptable.
Note 5: If this bit is set to “1”, XOUT turns “H”. The built-in feedback resistor remains being ON, so XIN turns pulled up to
XOUT (“H”) via the feedback resistor.
Note 6: Set port Xc select bit (CM04) to “1” before setting this bit to “1”. Can not write to both bits at the same time.
Note 7: This bit changes to “1” when shifting from high-speed/medium-speed mode to stop mode and at a reset. When shifting from
low-speed/low power dissipation mode to stop mode, the value before stop mode is retained.
Note 8: fc32 is not included. Do not set to “1” when using low-speed, low power dissipation or ring oscillator mode.
System clock control register 1 (Note 1)
Symbol
Address
When reset
CM1
000716
2016
Bit name
Function
Bit symbol
b7
b6
b5
b4 b3
b2
b1
b0
CM10
All clock stop control bit
(Note 4)
0 : Clock on
1 : All clocks off (stop mode)
CM15
XIN-XOUT drive capacity
select bit (Note 2)
0 : LOW
1 : HIGH
W
R
W
R
CM16
CM17
Reserved bit
Always set to
“0”
Ring oscillation stop bit
0 : Oscillation enabled
1 : Oscillation stopped (Note 5)
Main clock division
select bit 1 (Note 3)
0 0 : No division mode
0 1 : Division by 2 mode
1 0 : Division by 4 mode
1 1 : Division by 16 mode
b7 b6
0
Reserved bit
0 : Ceramic oscillation or crystal oscillation
1 : RC oscillation
XIN oscillation select bit
Always set to
“0”
0
Note 1: Set bit 0 of the protect register (address 000A16) to “1” before writing to this register.
Note 2: This bit changes to “1” when shifting from high-speed/middle-speed mode to stop mode or at reset. When shifting from
low-speed/low power dissipation mode to stop mode, the value before stop mode is retained.
Note 3: Can be selected when bit 6 of the system clock control register 0 (address 000616) is “0”. If “1”, division mode is fixed at 8.
Note 4: If this bit is set to “1”, XOUT turns “H”, and the built-in feedback resistor is ineffective. The mode of power control cannot
be shifted to the stop mode directly from the oscillator mode.
Note 5: This bit can be set to “1” only when both the main clock switch bit (CM22) and clock monitor bit (CM23) are set to “0” .
Moreover, this bit is automatically set to “0” if the main clock switch bit (CM22) is set to “1”.
Always set to
“0”
00
CM13
CM14
Clock Generating Circuit
Figure 1.8.4. System clock control registers 0 and 1