
R8C/14 Group, R8C/15 Group 9. Clock Generation Circuit
Rev.2.10 Jan 19, 2006 Page 41 of 253
REJ09B0164-0210
Figure 9.3 CM1 Register
System Clock Control Register 1
(1)
Symbol Address After Reset
CM1
0007h 20h
Bit Symbol Bit Name Function RW
NOTES :
1.
2.
3.
4.
5.
6.
7.
8.
When entering stop mode from high or middle speed mode, this bit is set to “1” (drive capacity HIGH).
Set the PRC0 bit in the PRCR register to “1” (write enable) before rewriting to this register.
b7 b6 b5 b4 b3 b2 b1 b0
00
CM10
All Clock Stop Control Bit
(4,7,8)
0 : Oscillates clock
1 : Stops all Clocks (stop mode)
RW
—
(b1)
Reserved Bit Set to “0”
RW
—
(b2)
Reserved Bit Set to “0”
RW
CM13
Port XIN-XOUT Sw itch Bit
(7)
0 : Input port P4_6, P4_7
1 : XIN-XOUT Pin
RW
CM14
Low-Speed On-Chip Oscillation Stop
Bit
(5,6,8)
0 : Low -speed on-chip oscillator on
1 : Low -speed on-chip oscillator off
RW
CM15
XIN-XOUT Drive Capacity Select Bit
(2)
0 : LOW
1 : HIGH
RW
CM17 RW
b7 b6
0 0 : No division mode
0 1 : Divide-by-2 mode
1 0 : Divide-by-4 mode
1 1 : Divide-by-16 mode
System Clock Division Select Bit 1
(3)
CM16 RW
When the CM10 bit is set to “1” (stop mode) or the CM05 bit in the CM0 register to “1” (main clock stops) and the
CM13 bit is set to “1” (XIN-XOUT pin), the XOUT (P4_7) pin becomes “H”.
When the CM13 bit is set to “0” (input ports, P4_6, P4_7), the P4_7 (XOUT) enters input mode.
In count source protect mode (Refer to
12.2 Count Source Protect Mode
), the value remains unchanged even if
the CM10 and CM14 bits are set.
When the CM06 bit is set to “0” (CM16, CM17 bits enabled), this bit becomes enabled.
If the CM10 bit is “1” (stop mode), the internal feedback resistor becomes disabled.
When the OCD2 bit is set to “0” (selects main clock), the CM14 bit is set to “1” (stops low-speed
on-chip oscillator). When the OCD2 bit is set to “1” (selects on-chip oscillator clock), the CM14 bit is set to “0”
(low -speed on-chip oscillator on). It remains unchanged even if it is set to “1”.
When using the voltage detection interrupt, CM14 bit is set to “0” (low-speed on-chip oscillator on).
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