Information

Chapter 16
Low-Leakage Wakeup Unit (LLWU)
16.1 Introduction
NOTE
For the chip-specific implementation details of this module's
instances see the chip configuration chapter.
The LLWU module allows the user to select up to 16 external pin sources and up to 8
internal modules as a wakeup source from low-leakage power modes. The input sources
are described in the device's chip configuration details. Each of the available wakeup
sources can be individually enabled.
The
RESET pin is an additional source for triggering an exit from low-leakage power
modes, and causes the MCU to exit both LLS and VLLS through a reset flow. The
LLWU_RST[LLRSTE] bit must be set to allow an exit from low-leakage modes via the
RESET pin. On a device where the RESET pin is shared with other functions, the explicit
port mux control register must be set for the RESET pin before the RESET pin can be
used as a low-leakage reset source.
The LLWU module also includes three optional digital pin filters: two for the external
wakeup pins and one for the RESET pin.
16.1.1 Features
The LLWU module features include:
• Support for up to 16 external input pins and up to 8 internal modules with individual
enable bits
• Input sources may be external pins or from internal peripherals capable of running in
LLS or VLLS. See the chip configuration information for wakeup input sources for
this device.
K20 Sub-Family Reference Manual, Rev. 2, Feb 2012
Freescale Semiconductor, Inc. 289