Microchip Technology AC320007, Руководство пользователя

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2. Overview
2.1 maXTouch
®
Capacitive Touchscreen Controller
The module touch screen interface is based on the Atmel maXTouch mXT336U Touch Controller and operates on the
touch sensor at connector J4. The touch controller scans the touch sensor and signals the host with an active-low
interrupt signal (~MXT_CHG on J2 & J3) when a new touch data is available. Data communication with the
maXTouch controller is performed over the I
2
C interface (on J2 & J3). The I
2
C address of the touch controller is fixed
at 0 x 4A, and is not configurable.
Note: The maXTouch has pull-up resistors on the I
2
C SCL (R17) and SDA (R16) lines. A pull-up resistor for the
maXTouch ~CHG interrupt signal is located at R18 (10k).
2.2 maXTouch
®
Controller Interface
Details of the maXTouch communication protocol are beyond the scope of this document. This module is pre-loaded
with a configuration already optimized for the maXTouch touch sensor and panel, hence the developer will only focus
on interfacing with the device. When developing the maXTouch controller interface during evaluation and host
development, care should be taken to avoid changing the maXTouch configuration or committing changes to NV
storage on the maXTouch controller. To start with host interface development, users need to leverage the existing
code available from MPLAB
®
Harmony, which is available at https://www.microchip.com/mplab/mplab-harmony .
For additional information regarding the maXTouch devices, refer to http://www.microchip.com .
Overview
©
2020 Microchip Technology Inc.
DS70005414B-page 4