sx8639 Semtech Corporation, sx8639 Datasheet - Page 31

no-image

sx8639

Manufacturer Part Number
sx8639
Description
Low Power, Capacitive Button And Wheel Touch Controller 8 Sensors With Enhanced Led Drivers And Proximity Sensing
Manufacturer
Semtech Corporation
Datasheet
SX8639
Low Power, Capacitive Button and Wheel Touch Controller
(8 sensors) with Enhanced LED Drivers and Proximity Sensing
ADVANCED COMMUNICATIONS & SENSING
DATASHEET
3.17 Smart Wake Up
The SX8639 offers a smart wake up mechanism (up to 6 keys) which allows waking-up from the Doze low power
mode to the Active mode in a secure/controlled way and not by any unintentional sensor activation.
Until the full correct wake-up sequence is entered, the SX8639 will remain in Doze mode. Any wrong key implies
the whole sequence to be entered again.
Please note that each key touch must be followed by a release to be validated.
Hence if a proximity sensor and a touch button part of the wake-up sequence are interleaved on the PCB (ie if you
cannot touch the button without triggering proximity detection) the smart wake up feature cannot be used since
the proximity sensor is not “released” before the buttons are touched. In this case the smart wakeup sequence
must be turned OFF.
The smart wake-up mechanism can also be disabled which implies that Doze mode can hence only be exited
from GPI or I2C command.
Revision 7_8, September 10
© 2010 Semtech Corp.
www.semtech.com
31

Related parts for sx8639