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.
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