HD64F3687GHV Datasheet, PDF (110/566 Pages) Renesas Technology Corp – Old Company Name in Catalogs and Other Documents

Section 5 Clock Pulse Generator
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.
Initial
Bit
Bit Name Value R/W Description
7
PMRC1 0
R/W Port C Function Select 1 and 2
6
PMRC0 0
R/W
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
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.
Rev. 3.00 Sep. 10, 2007 Page 76 of 528
REJ09B0216-0300