Clock Generator Module (CGM)
CGM Registers
MC68HC908AB32
—
Rev. 1.0
Technical Data
MOTOROLA
Clock Generator Module (CGM)
149
NOTE:
The multiplier select bits have built-in protection that prevents them from
being written when the PLL is on (PLLON = 1).
VRS[7:4] — VCO Range Select Bits
These read/write bits control the hardware center-of-range linear
multiplier L, which controls the hardware center-of-range frequency
f
VRS
9.6.1 PLL Control Register (PCTL)
when the PLLON bit in the PLL control register (PCTL) is set. (See
9.4.2.5 Special Programming Exceptions
VCO range select bits disables the PLL and clears the BCS bit in the
PCTL. (See
9.4.3 Base Clock Selector Circuit
and
for more information). Reset initializes
the bits to $6 to give a default range multiply value of 6.
NOTE:
The VCO range select bits have built-in protection that prevents them
from being written when the PLL is on (PLLON = 1) and prevents
selection of the VCO clock as the source of the base clock (BCS = 1) if
the VCO range select bits are all clear.
The VCO range select bits must be programmed correctly. Incorrect
programming may result in failure of the PLL to achieve lock.
Table 9-1. VCO Frequency Multiplier (N) Selection
MUL7:MUL6:MUL5:MUL4
VCO Frequency Multiplier (N)
0000
1
0001
1
0010
2
0011
3
1101
13
1110
14
1111
15
Summary of Contents for MC68HC908AB32
Page 1: ...MC68HC908AB32 D REV 1 0 MC68HC908AB32 HCMOS Microcontroller Unit TECHNICAL DATA ...
Page 2: ......
Page 68: ...FLASH Memory Technical Data MC68HC908AB32 Rev 1 0 68 FLASH Memory MOTOROLA ...
Page 84: ...EEPROM Technical Data MC68HC908AB32 Rev 1 0 84 EEPROM MOTOROLA ...
Page 390: ...Ordering Information Technical Data MC68HC908AB32 Rev 1 0 390 Ordering Information MOTOROLA ...
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