mcf5282 Freescale Semiconductor, Inc, mcf5282 Datasheet - Page 186

• Manufacturer Part Number: mcf5282
• Manufacturer: Freescale Semiconductor, Inc

Clock Module
A special loss-of-clock condition occurs when both the reference and the PLL fail. The failures may be
simultaneous, or the PLL may fail first. In either case, the reference clock failure takes priority and the
PLL attempts to operate in SCM. If successful, the PLL remains in SCM until the next reset. If the PLL
cannot operate in SCM, the system remains static until the next reset. Both the reference and the PLL must
be functioning properly to exit reset.
9.7.4.11 Loss of Clock in Stop Mode
Table 9-10
by the various clocking methods.
9-16
EXT
NRM
NRM
MODE
In
shows the resulting actions for a loss of clock in Stop Mode when the device is being clocked
X X X X
0 0 0 Off Off 0 Lose lock,
X 0 0 Off Off 1 Lose lock,
X
MCF5282 and MCF5216 ColdFire Microcontroller User’s Manual, Rev. 3
X
Table 9-10. Stop Mode Operation (Sheet 1 of 5)
f.b. clock,
reference
clock
f.b. clock,
reference
clock
Expected
Action at
Stop
PLL
—
Lose reference
clock
Regain
No regain
Regain clocks, but
don’t regain lock
No reference
clock regain
No f.b. clock
regain
During Stop
PLL Action
—
EXT
Stuck
NRM
Stuck
SCM–>
unstable
NRM
SCM–>
Stuck
MODE
Out
0
‘LK
0–>‘L
K
0–>
—
—
—
0
1
0–>
1
0–>
—
—
—
0
‘LC
1–>‘L
C
1–>
—
—
—
Freescale Semiconductor
Block LOCS and
LOCKS until
clock and lock
respectively
regain; enter
SCM regardless
of LOCEN bit
until reference
regained
Block LOCS and
LOCKS until
clock and lock
respectively
regain; enter
SCM regardless
of LOCEN bit
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