Datasheet

Section 5 Clock Pulse Generator
Rev. 3.00 Sep. 10, 2007 Page 76 of 528
REJ09B0216-0300
5.2.4 Clock Control/Status Register (CKCSR)
CKCSR selects the port C function, controls switching the system clocks, and indicates the system
clock state.
Bit Bit Name
Initial
Value
R/W Description
Port C Function Select 1 and 2
PMRC1 PMRC0 PC1 PC0
0 0 I/O I/O
1 0 CLKOUT I/O
0 1 (Open) OSC1 (external
clock input)
1 1 OSC2 OSC1
7
6
PMRC1
PMRC0
0
0
R/W
R/W
5 OSCBAKE 0 R/W External Clock Backup Enable
0: External clock backup disabled
1: External clock backup enabled
The external oscillation detecting circuit is enabled when
this bit is 1. When the external oscillator halt is detected
while this LSI operates on the external input signal, the
system clock source is automatically switched to the on-
chip oscillator regardless of the value of bit 4 in this
register.
Note: The external oscillation detecting circuit operates
on the on-chip oscillator clock. When this bit is set
to 1, do not set the on-chip oscillator to the standby
mode by the RCSTP bit in RCCR.