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Using a 7" TFT

Posted: Sat Aug 25, 2012 6:48 am
by recantha
Hi all.
I've picked up a used Portable DVD player with a 7" TFT screen. I'd love to be able to use it with the Pi but am a bit stuck trying to convert it or interface it. I've taken some pics of what comes off the screen - can anyone offer some advice?

Those letters/numbers on the ribbon are "LCA 0523"

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Re: Using a 7" TFT

Posted: Sat Aug 25, 2012 12:12 pm
by kaos
I suspect that patching into the display at that point may be an uphill battle. You will have to find out what protocol the panel uses, what is the pinout of the connector, find a matching connector (maybe you can salvage it from the player) and find some method of connecting to one of the Raspi display outputs (if your'e lucky the upcoming DSI interface board may be of help).

On the other hand, it is possible that lurking somewhere in the player is a standard composite video line, which you could plug straight into the Raspi video out connector. I've seen a hack doing that somewhere, although I've lost the link. In that case a portable DVD player was being hacked as a display for a digital camera, but the principle is the same. Note though, that the internal architecture of these players can vary, and there is nothing that says that the signal must at some point be converted to composite video.

--
Best regards, Kári.

Re: Using a 7" TFT

Posted: Sat Aug 25, 2012 2:59 pm
by recantha
Thanks for replying!

I have actually got the entire of the player. I've disassembled it and the boards I have are:
* The one with the power inlet (ribbon glued from that into...)
* The main board (with data and power connectors to...)
* The interface board (with ribbon cable to the display as per picture)
* The little sound card (I assume it is, it's marked TDK).

I _think_ I should be able to just get another interface board with composite in, or something but I'm a bit lost with all the different kinds...

Here's some more pics of the other bits (from above) - I'm using someone else's pics, but it's a virtually identical model.

Main board (next 3)
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Sound card
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Video interface card
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Power board:
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Re: Using a 7" TFT

Posted: Mon Aug 27, 2012 9:01 pm
by FalconXY
What you call the TDK sound card, is a high voltage drive for the LCD backlight.

From the pictures it seems mostly difficult to use that screen with the Pi.

I have bought a used 7" TFT with VGA input from ebay for about 50 Euros.
It's much easier. I only needed a HDMI to VGA active adapter and it works great.

Better not waste your time on that DVD screen.

Re: Using a 7" TFT

Posted: Mon Aug 27, 2012 9:17 pm
by magno23
i have found this datasheet for the VP77 chip, the one in your board is the VP77-LF but since this was the only one i could find i figure they are probably not so different.
http://www.datasheet.co.kr/datasheet-ht ... C.pdf.html

Re: Using a 7" TFT

Posted: Mon Aug 27, 2012 9:44 pm
by FalconXY
The PDF states that your LCD seems to be a low res display with ...x234 lines resolution.

Good enough for videos but bad for computers.
My 7" TFT is 800x600 (native) and can show up to 1024x768.

I would not recommend that you are trying more with your LCD.

Re: Using a 7" TFT

Posted: Tue Aug 28, 2012 7:33 am
by recantha
Right'o. Tis probably a dead horse that needs no flogging. :-)

What make/model is your 7" display?

Re: Using a 7" TFT

Posted: Tue Aug 28, 2012 2:17 pm
by FalconXY
Sorry, it seems to be a NoName-Touchscreen from 2006.
I have not tried the Touchscreen function with the Pi.

Re: Using a 7" TFT

Posted: Mon May 27, 2013 5:45 pm
by samspeed
Hey,

have anyone get screen with VP77-LF to work with RasPi ?
I got one screen with that processor, it was old in-dash dvd player
(Audiovox vme 9312ts).
It would be great to get at least picture to the screen.