EA FAQs

How to use the touch panel on EA DOGXL160-7 ?

How to use the touch panel on EA DOGXL160-7 ?

Frage:
I just purchased the EA DOGXL160-7 display and a touch panel. I am looking for data sheets on the above-mentioned product. The only thing I could
find on your website is the application example for the touch panel which shows how to connect the touch panel to an ATmega AVR processor and nothing else. This application example does not provide any information on how the touch panel works.

Antwort:
The touch panel EA TOUCH160-1 (which matches the EA DOGXL160-7) is an analogue, 4-wire, resistive touch display.
As you see, the 4 wires are connected to the 4 edges on the touch panel.

When

you press on it, there will be an electrical contact between the two

layers of the touch panel. Your ATmega will do something like this:

(1) connect 5V to the upper edge and 0V to the lower edge.
(2) read the voltage on the right/left edge

(3) connect 5V to left edge and 0V to the left edge
(4) read the voltag on the upper/lower edge

Example:
(2) read 2.5V and (4) reads 1V

This

2.5V reading tells you that the 'key press' was on a horizontal line

which is in the mid of the panel. And the second reading 1.0V indicates

the 'key press' on a vertical line near the right edge.
The 'key' was pressed on the coordinates where both lines intersect.

There's an interesting application note #341 on Atmel's web site:

www.atmel.com/dyn/resources/prod_documents/doc8091.pdf

The code that goes with it is here, if you search on 341:

www.atmel.com/dyn/products/app_notes.asp 

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