LCD touch panel and FPGA

Question

Hi,

I wanted to ask if I could interface a touch panel LCD with FPGA without using microcontrollers.

I've tried searching the internet for usefull info regarding this kind of interface but from what I saw, I need a microcontroller. Is it true (I have the DE1 board and I want to connect LCD to it)?

And another quick question: can anyone point me to some tutor of how to get the position of the drawing made on the touch screen?

I want to buy a touch screen LCD, but I want some kind I could interface with fpga using VHDL and read the coordinates.

Thanks,

Roy

altera_forum · Answer

You can use external ADC and FPGA io pins for apply voltage to matrix. (resestive matrix). Apply 0 to X, +3.3v to X'. Measure voltage at Y or Y'. Then set X and X' to input, Y to 0 and Y' to +3.3v. Measure voltage at X or X'.

http://en.wikipedia.org/wiki/resistive_touchscreen

altera_forum · Answer

Hi,

Ok, I see.

Can you refer me to some tutor regarding X and X'?

I lost you on this one...

And if, for instance, i'll buy this LCD:

http://cgi.ebay.com/3-2-tft-lcd-module-display-touch-panel-pcb-adapter-/200475566068?cmd=viewitem&pt=lh_defaultdomain_0&hash=item2ead465ff4

will I need also an external ADC?

Thanks,

Roy

altera_forum · Answer

First, you need to find the documentation for your LCD panel.

Only then you can know what you need to interface with it.

AFAIK, most nowadays have completly digital interfaces.

And yes, you can use a FPGA.

altera_forum · Answer

--- Quote Start ---

Hi,

Ok, I see.

Can you refer me to some tutor regarding X and X'?

I lost you on this one...

And if, for instance, i'll buy this LCD:

http://cgi.ebay.com/3-2-tft-lcd-module-display-touch-panel-pcb-adapter-/200475566068?cmd=viewitem&pt=lh_defaultdomain_0&hash=item2ead465ff4

will I need also an external ADC?

--- Quote End ---

Yes.

X and X'

http://www.divshare.com/download/11463401-4a9

320qvt-SPEC.pdf

Page 3

TOUCH PANEL X_LEFT

TOUCH PANEL X_RIGHT

For Y and Y'

TOUCH PANEL Y_DOWN

TOUCH PANEL Y_UP

looks like you panel have analog interface.

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LCD touch panel and FPGA

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