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Information on the resistive touch panel

Hello,

I am looking for information regarding the resistive touch panel for the DT043BTFT-TS.  The documenations that I found for this model, doesn't discuss the resistive touch panel at all.  I am assuming I need to connect PINS 40-43 to an IC-Touch Screen Controller but am unsure if it is a straight path connection or if there is other circuitry that needs to be included in my design.  I would appreciate any information that you can provide.  

Thank you,

Gary

Replies

engineering_seacomp's picture
engineering_seacomp
January 29, 2020

Hi Gary,

Resistive touch screen technology has been around for decades, and is very well documented via our friend Google. 

There are 2 ways to interface to a resistive touch screen.

1) Interfaced to a microcontroller directly with 4 pins (2 analogs, 2 digital)

2) or use a digitizer such as Microchip AR1021

Calibration is required with all resistive touch, but it's pretty simple.

Here are some hints on how to implement.

Please see:

https://www.dropbox.com/s/6jv2nh0g401r2b4/MAX11802_TouchScreen_Calibration_AN5296.pdf?dl=0

The calibration is really about displaying a dot on the screen at a particular location  (X,Y), then measuring the reported value (Cx,Cy) , then adjusting by that much (X'=X-Cx,Y'=Y-Cy).  With this method, you get accurate touches.  

Show a dot in each of the four quadrants at the factory as a one time calibration, and then store the values in NVM, forever.