MMCCMB2107 Freescale, MMCCMB2107 Datasheet - Page 237

• Manufacturer Part Number: MMCCMB2107
• Manufacturer: Freescale

Specifications of MMCCMB2107

• Lead Free Status / RoHS Status: Not Compliant

MMC2107 – Rev. 2.0
MOTOROLA
WITH TIGHT LOCK
CRITERIA
START
NUMBER OF FEEDBACK
REFERENCE CYCLES
CYCLES ELAPSED
After lock is detected, the lock circuit continues to monitor the reference
and feedback frequencies using the alternate count and compare
process. If the counters do not match at any comparison time, then the
LOCK flag is cleared to indicate that the PLL has lost lock. At this point,
the lock criteria is tightened and the lock detect process is repeated.
The alternate count sequences prevent false lock detects due to
frequency aliasing while the PLL tries to lock. Alternating between tight
and relaxed lock criteria prevents the lock detect function from randomly
toggling between locked and non-locked status due to phase
sensitivities.
non-locked conditions.
In external clock mode, the PLL is disabled and cannot lock.
AND COMPARE
COUNT N
Freescale Semiconductor, Inc.
For More Information On This Product,
Figure 10-6. Lock Detect Sequence
REFERENCE COUNT
FEEDBACK COUNT
Go to: www.freescale.com
Figure 10-6
IN SAME COUNT/COMPARE SEQUENCE
Clock Module
CONDITION AND NOTIFY
FEEDBACK COUNT = N
REFERENCE COUNT =
AND NOTIFY SYSTEM OF LOSS
SET RELAXED LOCK
LOCK DETECTED.
SYSTEM OF LOCK
SET TIGHT LOCK CRITERIA
LOSS OF LOCK DETECTED
OF LOCK CONDITION
CONDITION
shows the sequence for detecting locked and
REFERENCE COUNT =
FEEDBACK COUNT = N + K
IN SAME COUNT/COMPARE SEQUENCE
AND COMPARE NUMBER
REFERENCE COUNT
OF FEEDBACK CYCLES
REFERENCE CYCLES
FEEDBACK COUNT
COUNT N + K
ELAPSED
Functional Description
Technical Data
Clock Module
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