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1-25
Mitsubishi microcomputers
M30240 Group
SINGLE-CHIP 16-BIT CMOS MICROCOMPUTER
Preliminary Specifications REV. E
Specifications in this manual are tentative and subject to change
Clock Control
2.8.3 Peripheral function clock
2.8.3.1 f1, f8, f32
The clock for the peripheral devices is derived from the main clock or by dividing it by 8 or 32. The
peripheral function clock is stopped by stopping the main clock or by setting the WAIT peripheral func-
tion clock stop bit (bit 2 at 0006
16
) to “1” and then executing a WAIT instruction.
2.8.3.2 fAD
This clock has the same frequency as the main clock and is used for A-D conversion.
2.8.4 Clock Output
In single-chip mode, the clock output function select bits (bits 0 and 1 at address 0006
16
) enable f8 or
f32 to be output from the P37/CLKOUT pin. When the WAIT peripheral function clock stop bit (bit 2 at
address 0006
16
) is set to “1”, the output of f8 and f32 stops when a WAIT instruction is executed.
Figure 1.13 shows the system clock control registers 0 and 1.
Figure 1.13: System clock control registers 0 and 1
Note 1: Set bit 0 of the protect register (address 000A
16
) to “1”
before writing to this register.
Note 2: Changes to “1” when shifting to stop mode.
Note 3: Can be selected when bit 6 of system clock control
register 0 (address 0006
16
) is “0”. If “1”, division mode if fixed at 8.
System clock control register 0 (Note 1)
b7
b6
b5
b4
b3
b2
b1
b0
Note 1: Set bit 0 of the protect register (address 000A
16
) to “1” before writing
to this register.
Note 2: Changes to “1” when shifting to stop mode.
System clock control register 1 (Note 1)
Symbol
CM1
Address
0007
16
When reset
20
16
Bit name
Function
Bit symbol
CM10
b7
b6
b5
b4
0
b3
0
b2
0
b1
0
b0
All clock stop control bit
0 : Clock on
1 : All clocks off (stop mode)
CM15
IN
-X
OUT
drive capacity
X
0 : LOW
W
R
CM16
CM17
Reserved bit
Always set to
“0”
Reserved bit
Always set to
“0”
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
Reserved bit
Always set to
“0”
Reserved bit
Always set to
“0”
Symbol
CM0
Address
0006
16
When reset
48
16
Bit name
Function
Bit symbol
0 0 : I/O port P3
7
0 1 : Invalid
1 0 : f
8
output
1 1 : f
32
output
0 : Do not stop f
1
, f
, f
in wait mode
1 : Stop f
1
, f
8
, f
32
in wait mode
b1 b0
CM01
CM02
CM00
Clock output function
select bit
WAIT peripheral function
clock stop bit
W
R
CM06
Main clock division select
bit 0 (Note 2)
0 : CM16 and CM17 valid
1 : Division by 8 mode
Reserved bit
Always set to "1"
Reserved bit
Always set to "0"
Reserved bit
Always set to "0"
Reserved bit
Always set to "0"