TC1796
System Units (Vol. 1 of 2)
Clock System and Control
User’s Manual 3-15 V2.0, 2007-07
Clock, V2.0
VCO Operating Range
The VCO can be selected for three operating ranges by programming the
PLL_CLC.VCOSEL bit field. Table 3-5 defines the min./max. f
VCO
frequency as well as
the VCO base frequency f
VCObase
. This is the base VCO frequency when no PLL input
clock f
P
is connected.
Table 3-5 VCO Operating Range Selection
Bit PLL_CLC.
VCOSEL
f
VCOmin
f
VCOmax
f
VCObase
1)
1) f
VCObase
is the free-running operation frequency of the PLL when no input clock is available.
f
OSCmin
2)
2) This is the minimum oscillator frequency to allow oscillator run detection to work properly.
Unit
00
B
400 500 approx. 140 - 320 1.5 MHz
01
B
500 600 approx. 150 - 400 1.75 MHz
10
B
3)
3) This is the default value after a power-on reset.
600 700 approx. 200 - 480 2 MHz
11
B
Reserved, do not use this combination