M16C Datasheet, PDF (41/262 Pages) Mitsubishi Electric Semiconductor – SINGLE-CHIP 16-BIT CMOS MICROCOMPUTER

Preliminary Specifications REV.B
Mitsubishi microcomputers
Specifications in this manual are tentative and subject to change.
M16C / 6N Group
SINGLE-CHIP 16-BIT CMOS MICROCOMPUTER
Clock Generating Circuit
Figure 5-4 shows the system clock control registers 0 and 1.
System clock control register 0 (Note 1)
b7 b6 b5 b4 b3 b2 b1 b0
Symbol
CM0
Address
000616
When reset
4816
Bit symbol
CM00
CM01
CM02
CM03
Bit name
Clock output function
select bit
WAIT peripheral function
clock stop bit
XCIN-XCOUT drive capacity
select bit (Note 2)
Function
b1 b0
0 0 : I/O port P57
0 1 : fC output
1 0 : f8 output
1 1 : f32 output
0 : Do not stop f2, f8, f32 in wait mode
1 : Stop f2, f8, f32 in wait mode
0 : LOW
1 : HIGH
RW
CM04
CM05
Port XC select bit
Main clock (XIN-XOUT)
stop bit (Note 3, 4 and 5)
0 : I/O port
1 : XCIN-XCOUT generation
0 : On
1 : Off
CM06
Main clock division select 0 : CM16 and CM17 valid
bit 0 (Note 2)
1 : Division by 8 mode
CM07
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: When entering power saving mode, main clock stops using this bit. When returning from stop
mode and operating with XIN, set this bit to “0”. When main clock oscillation is operating by
itself, set 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 ON, so XIN turns pulled
up to XOUT ("H") via the feedback resistor.
Note 6: Set port Xc select bit (CM04) to “1” before writing to this bit. The both bits can not be written at
the same time.
System clock control register 1 (Note 1)
b7 b6 b5 b4 b3 b2 b1 b0
0 00 0
Symbol
CM1
Address
000716
When reset
2016
Bit symbol
Bit name
CM10
All clock stop control bit
(Note 4)
Reserved bit
Function
0 : Clock on
1 : All clocks off (stop mode)
Always set to “0”
RW
Reserved bit
Always set to “0”
Reserved bit
Always set to “0”
Reserved bit
Always set to “0”
CM15
CM16
CM17
XIN-XOUT drive capacity
select bit (Note 2)
Main clock division
select bit 1 (Note 3)
0 : LOW
1 : HIGH
b7 b6
0 0 : No division mode
0 1 : Division by 2 mode
1 0 : Division by 4 mode
1 1 : Division by 16 mode
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: 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 turns null.
Figure 5-4. Clock control registers 0 and 1
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