This application note describes ways to reduce system
current consumption with the use of the Ultra
Low-power Wake-up (ULPWU) module. The
PIC16F684 and PIC16F88X are examples of devices
with this feature.
The primary use of this module is as an ULPWU timer,
but its functionality can be expanded to function as a
temperature sensor and/or a low-voltage detector. The
main and expanded functions of this module are
explained in this document.
Many low-power applications require that the
microprocessor wake-up from a Sleep state on a
periodic basis to check the status of some signal. It can
then react based on a measurement of that signal and
go back to Sleep until the next timed wake-up. This is
a widely used method for reducing overall system AN879
Using the Microchip Ultra Low-Power Wake-Up Module
current consumption. These types of applications
Authors: Ruan Lourens require a low-power periodic wake-up and can be
Jose Benevides accomplished by activating a low-power timer prior to
Jonathan Dillon placing the device in a Sleep mode. Upon rollover, the
Microchip Technology Inc. timer interrupt can then wake-up the part after some
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