P+ driving a recycled junked laptop LCD


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Alvie and I just got some HDMI prototype wings in the mail and it is on our task list to validate them as soon as possible. Once they are proven we will initiate a batch for sale in the store. In the meantime you can probably cut the end off an old HDMI cable and wire it directly to the Papilio to get started with... The original Xilinx app notes for HDMI testing did that and were able to get good results at lower resolutions.



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I was thinking over the weekend that it might be a really cool idea to make a MegaWing that had HDMI input that would then use that input to drive salvaged LVDS laptop monitors...


There are boards that do exactly this for $10-$20 depending on features, just do a search for universal TFT driver on greedbay. They use a commodity ASIC rather than FPGA so there's a lot less hacking potential, but if all you want to do is turn a salvaged TFT into a monitor there's no need to reinvent the wheel.


I do like the idea of being able to drive a TFT panel directly from the FPGA to display its own content though.

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  • 4 years later...
On 2012. 9. 27. at 3:23 PM, alex said:

I had a broken laptop that was given to me and after it sat there gathering dust for a long time I decided to take the LCD apart since I had nothing to lose if nothing came of it. Once I exposed the LCD panel, I was pleasantly surprised to find a datasheet online with electrical, timing specs, even a pinout for the LCD panel, a QD15TL02 type which is a 15" panel with 1280x800 pixel native resolution.

The panel requires about 10V (5W) for the CCFL inverter and 3.3V (1.4W) for the logic, you can see below a 3.3V linear regulator I found in my junkbox bolted to a heatsink which I'm using currently do bring up the LCD panel. Additionally the panel is driven with four LVDS differential pairs, three for data and one for clock.


Currently I have all the signals soldered to a small perfboard with a header that plugs into wing slots BH and AL. The reason I chose these slots is because I need differential signal pins and no single wing alone provides these.

Eventually I plan to make a small circuit board with a switch mode regulator that will fit in the corner seen in the picture above (the three screw holes). The PCB will have a barrel connector for power, a small pot for adjusting the brightness and a HDMI connector for the signals. Below is an eagle board I submitted to Batchpcb the other day. The LCD panel is not HDMI capable but the HDMI connector is ubiquitous and ideally suited for passing the high frequency data signals required.


On the right hand side above is a Pap wing with an HDMI connector which I plan to use to connect to the LCD panel but by reprogramming the FPGA to talk TMDS, that wing should be able to be used with any proper HDMI sink. I can't wait to use that wing to try out Mike's Dvid_test on my HDMI monitor.

The ground planes in the picture above have not been rendered for clarity. I've already received the components from Digikey (in less than 2 days no less) but Batchpcb has been having issues for the last few days and I only just today managed to buy my design, now a few weeks waiting for boards to turn up :(


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Dear alex

It's been a so long time, But I do want to implement HDMI to my FPGA.

But I need your HDMI PCB file, Can you send me a HDMI PCB files?


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Carter Lee,

Here is the latest design that we have for an HDMI wing. We have confirmed that it works, and I actually manufactured 100 of these, and Alvie has this working with the ZPUino soft processor. But sadly, we never found the time to properly release this wing so it is just sitting around. I mentioned in another post that if you send us your shipping information at support@gadgetfactory.net I will send you one of these wings to play with for free.



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