Allwinner A20 - 1.15. TP

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1.15. TP

1.15.1. Overview

The TP controller is a 4-wire resistive touch screen controller, including 12-bit resolution A/D

converter. Especially, it provides the ability of dual touch detection. The controller through the

implementation of the two A/D conversion has been identified by the location of the screen of single

touch, in addition to measurable increase in pressure on the touch screen.

It features:

 12-bit SAR type A/D converter

 4-wire I/F

 Dual touch detection

 Touch-pressure measurement (Support programmable threshold)

 Sampling frequency up to 2MHz

 Single-Ended conversion of touch screen inputs and ratiometric conversion of touch screen inputs

 TACQ up to 262ms

 Median and averaging filter to reduce noise

 Pen down detection, with programmable sensitivity

 Support X, Y change