Information

14.4.2.2 Stop mode exit sequence
Exit from a low-power stop mode is initiated either by a reset or an interrupt event. The
following sequence then executes to restore the system to a run mode (RUN or VLPR):
1. The on-chip regulator in the PMC and internal power switches are restored.
2. Clock generators are enabled in the MCG.
3. System and bus clocks are enabled to all masters and slaves.
4. The CPU clock is enabled and the CPU begins servicing the reset or interrupt that
initiated the exit from the low-power stop mode.
14.4.2.3 Aborted stop mode entry
If an interrupt or a reset occurs during a stop entry sequence, the SMC can abort the
transition early and return to RUN mode without completely entering the stop mode. An
aborted entry is possible only if the reset or interrupt occurs before the PMC begins the
transition to stop mode regulation. After this point, the interrupt or reset is ignored until
the PMC has completed its transition to stop mode regulation. When an aborted stop
mode entry sequence occurs, the SMC's PMCTRL[STOPA] is set to 1.
Restriction
Aborted entry to a stop mode is not supported when an interrupt
occurs during a transition from VLPR mode to any stop mode.
14.4.2.4 Transition to wait modes
For wait modes (WAIT and VLPW), the CPU clock is gated off while all other clocking
continues, as in RUN and VLPR mode operation. Some modules that support stop-in-
wait functionality have their clocks disabled in these configurations.
14.4.2.5 Transition from stop modes to Debug mode
The debugger module supports a transition from STOP, WAIT, VLPS, and VLPW back
to a Halted state when the debugger has been enabled, that is, ENBDM is 1. As part of
this transition, system clocking is re-established and is equivalent to the normal RUN and
VLPR mode clocking configuration.
Chapter 14 System Mode Controller
K20 Sub-Family Reference Manual, Rev. 2, Feb 2012
Freescale Semiconductor, Inc. 273