R8C/1A Group, R8C/1B Group
10. Clock Generation Circuit
Rev.1.30
Dec 08, 2006
Page 63 of 315
REJ09B0252-0130
Figure 10.5
HRA0 Register
High-Speed On-Chip Oscillator Control Register 0
(1)
Symbol
Address
After Reset
HRA0
0020h
00h
Bit Symbol
Bit Name
Function
RW
NOTES :
1. Set the PRC0 bit in the PRCR register to 1 (w rite enable) before rew riting the HRA0 register.
2.
3.
Change the HRA01 bit under the follow ing conditions.
• HRA00 = 1 (high-speed on-chip oscillation)
• The CM14 bit in the CM1 register = 0 (low -speed on-chip oscillator on)
When setting the HRA01 bit to 0 (low -speed on-chip oscillator selected), do not set the HRA00 bit to 0 (high-speed
on-chip oscillator off) at the same time.
Set the HRA00 bit to 0 after setting the HRA01 bit to 0.
—
(b7-b2)
Reserved bits
Set to 0.
RW
HRA00
RW
HRA01
RW
High-speed on-chip oscillator enable
bit
0 : High-speed on-chip oscillator off
1 : High-speed on-chip oscillator on
High-speed on-chip oscillator select
bit
(2)
0 : Selects low -speed on-chip oscillator.
(3)
1 : Selects high-speed on-chip oscillator.
0 0
0 0 0 0
b3 b2 b1 b0
b7 b6 b5 b4
