Datasheet

Section 5 Clock Pulse Generators
Rev. 1.50 Sep. 18, 2007 Page 73 of 584
REJ09B0240-0150
5.2.1 RC Control Register (RCCR)
RCCR controls the on-chip oscillator.
Bit Bit Name
Initial
Value R/W Description
7 RCSTP 0 R/W On-Chip Oscillator Standby
The on-chip oscillator standby state is entered by setting
this bit to 1.
6 FSEL 1 R/W Frequency Select for On-Chip Oscillator
The system clock is generated by dividing this clock while
this clock is supplied to timer RC or timer RD (φ
40M
).
0: 32MHz
1: 40MHz
5 VCLSEL 0 R/W Power Supply Select for On-Chip Oscillator
0: Selects VBGR
1: Selects VCL
When VCL is selected, the accuracy of the on-chip
oscillator frequency cannot be guaranteed.
4 to 2  All 0  Reserved
These bits are always read as 0.
1
0
RCPSC1
RCPSC0
1
0
R/W
R/W
Division Ratio Select for On-Chip Oscillator
These bits select the operating clock frequency in active
mode or sleep mode when the on-chip oscillator is in use.
The division ratio for dividing R
OSC
changes right after
rewriting this bit.
These bits can only be written to when the CKSTA bit in
CKCSR is 0.
0X: R
OSC
/2
10: R
OSC
/4
11: R
OSC
/8
[Legend]
X: Don't care