XC908AS60ACFU Motorola Semiconductor Products, XC908AS60ACFU Datasheet - Page 178

• Manufacturer Part Number: XC908AS60ACFU
• Description: MC68HC908AZ60A, MC68HC908AS60A Hcmos Microcontroller Unit Technical Data
• Manufacturer: Motorola Semiconductor Products

Clock Generator Module (CGM)
Technical Data
178
NOTE:
For proper operation,
Exceeding the recommended maximum bus frequency or VCO
frequency can crash the MCU.
5. Calculate the bus frequency, f
6. If the calculated f
7. Using the value 4.9152 MHz for f
8. Calculate the VCO center-of-range frequency, f
9. Program the PLL registers accordingly:
f
application, select another f
range multiplier, L. The linear range multiplier controls the
frequency range of the PLL.
center-of-range frequency is the midpoint between the minimum
and maximum frequencies attainable by the PLL.
BUSDES
a. In the upper four bits of the PLL programming register (PPG),
b. In the lower four bits of the PLL programming register (PPG),
Clock Generator Module (CGM)
Example: f
program the binary equivalent of N.
program the binary equivalent of L.
Example:
.
Example:
CGMVRS
f
BUS
f
f
bus
CGMVRS
f
BUS
L
CGMVRS
L
=
is not within the tolerance limits of your
=
=
=
------------------------------- -
4.9152 MHz
round
= 7 × 4.9152 MHz = 34.4 MHz
f
----------------------- -
32 MHz
------------------- -
CGMVCLK
32 MHz
–
= L × f
4
f
4
BUSDES
CGMVCLK


BUS
f
----------------------- -
CGMVCLK
f
=
NOM
NOM
NOM
, and compare f
8 MHz
or another f
=
, calculate the VCO linear
≤
MC68HC908AZ60A — Rev 2.0
7
f
--------------- -


NOM
2
RCLK
CGMVRS
.
BUS
.
with
MOTOROLA
. The