mc9s12c32mpb16 Freescale Semiconductor, Inc, mc9s12c32mpb16 Datasheet - Page 656

• Manufacturer Part Number: mc9s12c32mpb16
• Description: Hcs12 Microcontrollers
• Manufacturer: Freescale Semiconductor, Inc

Appendix A Electrical Characteristics
A.4.3
The oscillator provides the reference clock for the PLL. The PLL´s Voltage Controlled Oscillator (VCO)
is also the system clock source in self clock mode.
A.4.3.1
This section describes the selection of the XFC components to achieve a good filter characteristics.
The following procedure can be used to calculate the resistance and capacitance values using typical values
for K
The grey boxes show the calculation for f
for f
The VCO Gain at the desired VCO frequency is approximated by:
The phase detector relationship is given by:
i
656
ch
is the current in tracking mode.
OSC
1
, f
1
= 4MHz and a 25MHz bus clock.
f
and i
osc
Phase Locked Loop
XFC Component Selection
ch
from
refdv+1
K
V
1
Table
=
K
K
Φ
A-17.
f
ref
1
=
Figure A-2. Basic PLL Functional Diagram
⋅
V
e
DDPLL
–
(
---------------------- -
f
K
MC9S12C-Family / MC9S12GC-Family
i
1
ch
1
–
⋅
D
f
1V
VCO
f
vco
⋅
cmp
K
Cp
=
)
Cs
V
= 50MHz and f
–
Detector
Loop Divider
Phase
Rev 01.23
100
synr+1
KF
R
1
⋅
e
= 316.7Hz/Ω
(
--------------------- -
60 50
–
100
–
ref
= 1MHz. E.g., these frequencies are used
XFC Pin
)
= -90.48MHz/V
1
2
VCO
KV
Freescale Semiconductor
f
vco