Clock Generator Module (CGMC)
Technical Data
MC68HC908GP32
•
MC68HC08GP32
—
Rev. 6
126
Clock Generator Module (CGMC)
MOTOROLA
AUTO — Automatic Bandwidth Control Bit
This read/write bit selects automatic or manual bandwidth control.
When initializing the PLL for manual operation (AUTO = 0), clear the
ACQ bit before turning on the PLL. Reset clears the AUTO bit.
1 = Automatic bandwidth control
0 = Manual bandwidth control
LOCK — Lock Indicator Bit
When the AUTO bit is set, LOCK is a read-only bit that becomes set
when the VCO clock, CGMVCLK, is locked (running at the
programmed frequency). When the AUTO bit is clear, LOCK reads as
logic 0 and has no meaning. The write one function of this bit is
reserved for test, so this bit must
always
be written a 0. Reset clears
the LOCK bit.
1 = VCO frequency correct or locked
0 = VCO frequency incorrect or unlocked
ACQ — Acquisition Mode Bit
When the AUTO bit is set, ACQ is a read-only bit that indicates
whether the PLL is in acquisition mode or tracking mode. When the
AUTO bit is clear, ACQ is a read/write bit that controls whether the
PLL is in acquisition or tracking mode.
In automatic bandwidth control mode (AUTO = 1), the last-written
value from manual operation is stored in a temporary location and is
recovered when manual operation resumes. Reset clears this bit,
enabling acquisition mode.
1 = Tracking mode
0 = Acquisition mode
Address:
$0037
Bit 7
6
5
4
3
2
1
Bit 0
Read:
AUTO
LOCK
ACQ
0
0
0
0
R
Write:
Reset:
0
0
0
0
0
0
0
0
= Unimplemented
R
= Reserved
Figure 7-5. PLL Bandwidth Control Register (PBWC)
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Freescale Semiconductor, Inc.
For More Information On This Product,
Go to: www.freescale.com
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