R01UH0092EJ0110 Rev.1.10
Page 87 of 807
Jul 31, 2012
M16C/64C Group
8. Clock Generator
8.2.2
System Clock Control Register 0 (CM0)
Set the PRC0 bit in the PRCR register to 1 (write enabled) before rewriting this register.
See Table 9.3 “Clock-Related Bit Setting and Modes” to select a clock and mode.
CM01 and CM00 (Clock output function select bit) (b1-b0)
The CLKOUT pin outputs can be selected. These bits are enabled when the PCLK5 bit in the PCLKR
register is set to 0 in single-chip mode. When the PCLK5 bit is 1, set bits CM01 and CM00 to 00b. Table
8.4 lists CLKOUT Pin Functions in Single-Chip Mode.
Table 8.4
CLKOUT Pin Functions in Single-Chip Mode
PCLKR Register
CM0 Register
CLKOUT Pin Output
PCLK5 bit
CM01 bit
CM00 bit
0
0
0
I/O port
0
0
1
fC is output
0
1
0
f8 is output
0
1
1
f32 is output
1
0
0
f1 is output
Only set the combinations listed above.
b7 b6 b5 b4
b1
b2
b3
System Clock Control Register 0
Symbol
CM0
Address
0006h
Bit Symbol
Bit Name
RW
CM00
Reset Value
0100 1000b
RW
b0
Function
b1 b0
0 0 : I/O port
0 1 : Output fC
1 0 : Output f8
1 1 : Output f32
CM01
CM02
Wait mode peripheral
function clock stop bit
0 : Peripheral function clock f1 does not
stop in wait mode
1 : Peripheral function clock f1 stops in
wait mode
CM03
CM04
Port XC select bit
0 : I/O port
1 : XCIN-XCOUT oscillation function
CM05
Main clock stop bit
0 : On
1 : Off
CM06
Main clock division
select bit 0
System clock select bit
0 : Bits CM16 and CM17 in the CM1
register enabled
1 : Divide-by-8 mode
CM07
RW
RW
RW
RW
RW
RW
0 : Low
1 : High
XCIN-XCOUT drive capacity
select bit
Clock output function select
bit (enabled in single-chip
mode only)
0 : Main clock, PLL clock, or on-chip
oscillator clock
1 : Sub clock
Содержание M16C Series
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