Functional Description - NXP Semiconductors MKL27Z128VFM4 Reference Manual

Table of Contents

Pin Filter 2 was not a wakeup source

Pin Filter 2 was a wakeup source

Digital Filter On External Pin

Controls the digital filter options for the external pin detect.

Filter disabled

Filter posedge detect enabled

Filter negedge detect enabled

Filter any edge detect enabled

This field is reserved.

This read-only field is reserved and always has the value 0.

Filter Pin Select

Selects 1 out of the 16 wakeup pins to be muxed into the filter.

Select LLWU_P0 for filter

Select LLWU_P15 for filter

18.5 Functional description

Thie low-leakage wakeup unit (LLWU) module allows internal peripherals and external

input pins as a source of wakeup from low-leakage modes.

It is operational only in LLS and VLLSx modes.

The LLWU module contains pin enables for each external pin and internal module. For

each external pin, the user can disable or select the edge type for the wakeup with the

following options:

• Falling-edge

• Rising-edge

• Either-edge

When an external pin is enabled as a wakeup source, the pin must be configured as an

The LLWU implements optional 3-cycle glitch filters, based on the LPO clock. A

detected external pin is required to remain asserted until the enabled glitch filter times

out. Additional latency of up to 2 cycles is due to synchronization, which results in a total

of up to 5 cycles of delay before the detect circuit alerts the system to the wakeup or reset

event when the filter function is enabled. Two wakeup detect filters are available for

selected external pins. Glitch filtering is not provided on the internal modules.

Freescale Semiconductor, Inc.

LLWU_FILT2 field descriptions (continued)

KL27 Sub-Family Reference Manual , Rev. 5, 01/2016

Chapter 18 Low-Leakage Wakeup Unit (LLWU)