Information

• External pin wakeup inputs, each of which is programmable as falling-edge, rising-
edge, or any change
• Wakeup inputs that are activated if enabled after MCU enters a low-leakage power
mode
• Optional digital filters provided to qualify an external pin detect and RESET pin
detect. When entering VLLS0, the filters are disabled and bypassed.
16.1.2 Modes of operation
The LLWU module becomes functional on entry into a low-leakage power mode. After
recovery from LLS, the LLWU is immediately disabled. After recovery from VLLS, the
LLWU continues to detect wakeup events until the user has acknowledged the wakeup
via a write to the PMC_REGSC[ACKISO] bit.
16.1.2.1 LLS mode
The LLWU module provides up to 16 external wakeup inputs and up to 8 internal module
wakeup inputs. An LLS reset event can be initiated via assertion of the RESET pin.
Wakeup events due to external wakeup inputs and internal module wakeup inputs result
in an interrupt flow when exiting LLS. A reset event due to RESET pin assertion results
in a reset flow when exiting LLS.
NOTE
The LLWU interrupt must not be masked by the interrupt
controller to avoid a scenario where the system does not fully
exit Stop mode on an LLS recovery.
16.1.2.2 VLLS modes
The LLWU module provides up to 16 external wakeup inputs and up to 8 internal module
wakeup inputs. A VLLS reset event can be initiated via assertion of the RESET pin. All
wakeup and reset events result in VLLS exit via a reset flow.
16.1.2.3 Non-low leakage modes
The LLWU is not active in all non-low leakage modes where detection and control logic
are in a static state. The LLWU registers are accessible in non-low leakage modes and are
available for configuring and reading status when bus transactions are possible.
Introduction
K20 Sub-Family Reference Manual, Rev. 2, Feb 2012
290 Freescale Semiconductor, Inc.