MC68HC708XL36 FREESCALE [Freescale Semiconductor, Inc], MC68HC708XL36 Datasheet - Page 93

• Manufacturer Part Number: MC68HC708XL36
• Description: HCMOS Microcontroller Unit
• Manufacturer: FREESCALE [Freescale Semiconductor, Inc]

Special
Programming
Exceptions
11-cgm1m_a
MOTOROLA
NOTE:
For proper operation,
Exceeding the recommended maximum bus frequency or VCO
frequency can crash the MCU.
6. Using the value 4.9152 MHz for f
7. Calculate the VCO center-of-range frequency, f
8. Program the PLL registers accordingly:
The programming method described in
page 92 does not account for two possible exceptions. A value of 0
for N or L is meaningless when used in the equations given. To
account for these exceptions:
•
•
Freescale Semiconductor, Inc.
For More Information On This Product,
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.
a. In the upper four bits of the PLL programming register (PPG),
b. In the lower four bits of the PLL programming register (PPG),
A 0 value for N is interpreted the same as a value of 1.
A 0 value for L disables the PLL and prevents its selection as the
source for the base clock. (See
page 94.)
program the binary equivalent of N.
program the binary equivalent of L.
Go to: www.freescale.com
Example: f
Example:
CGM
vrs
L
= 7
f
vrs
f
=
vrs
L
–
round
=
= L
f
4.9152 MHz = 34.4 MHz
vclk
------------------------------- -
4.9152 MHz
32 MHz
Base Clock Selector Circuit
f
nom
nom
--------- -
f
f
f
------------- -
nom
vclk
nom
2
Programming the PLL
, calculate the VCO linear
=
7
Functional Description
vrs
. The
MC68HC708XL36
on
CGM
on
93