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Interfacing an LCD display to the Pi

Posted: Sun Jun 17, 2018 2:32 pm
by FruityNutPi
I have here a broken photoframe with an intact 7in LCD, LG Philips - LB070WV1 (TD)(03). Its an excellent high contrast display so it occurred to me that it might be useful for one of my projects on the Raspberry Pi. Having had a look at the hardware however, the ribbon cable that attaches to the main board in the photo frame is wider and has differently spaced connectors so is not a direct fit for the interface on the Pi. It is, however a matching fit for the ribbon connector on the controller board to the rear of the 3.5in Pi display that I have and the connector spacing is identical.

I have yet to install the driver for the 3.5in LCD display and test it, but I was wondering, once I get the 3.5in display working, whether connecting the 7in display to this board is this likely to work? If it does, then is it possible to obtain the controller boards separately?

Re: Interfacing an LCD display to the Pi

Posted: Sun Jun 17, 2018 3:56 pm
by HawaiianPi
LCD controller boards are usually panel specific. So the controller for one likely won't work on another (unless the 2 panels have nearly identical specs). You can find controller boards on ebay and other sites, but you'll need to find one that is compatible with your specific display panel.

Re: Interfacing an LCD display to the Pi

Posted: Sun Jun 17, 2018 6:14 pm
by FruityNutPi
HawaiianPi, I did wonder about whether they were specific to the LCD so thanks for confirming that. I didn't know whether there are particular cabling or data bus standards on the panels themselves. I am struggling to find any separate controller boards on eBay so maybe I have not hit upon the correct search terms, but there are plenty of complete assemblies. I know that this panel is 7in and 800x600 and the model number so I have some clues so apart from physical resemblance and screen resolution I guess it would be tricky to be sure whether a particular controller would work. Its a shame as it has a very nice sharp display.

Re: Interfacing an LCD display to the Pi

Posted: Mon Jun 18, 2018 11:59 am
by pksato
Hi,
I found this datasheet of some LB070WV1 panel.
It use a LVTTL (3v3) parallel interface, can be connected to Raspberry Pi DPI (Parallel Display Interface).
Also, need to provide the backlight power (can be removed from original circuit).
Using DPI you lost most of GPIO pins.

Re: Interfacing an LCD display to the Pi

Posted: Mon Jun 18, 2018 1:46 pm
by FruityNutPi
Thank you for finding this datasheet, which is very helpful. Also I I am grateful that you have confirmed that it can be connected to the Pi DPI interface, although as you point out, means that one loses more than half of the GPIO pins. Backlight power should not be a problem as the power supply is on a separate daughterboard which can easily be removed.

It seems that the driver software contains options for 3.5, 4, 5 an 7in displays with a resolution of 800x480 which is the resolution of this panel. It remains to be seen whether the controller hardware will drive it to that resolution though.

It would ne interesting to get the datasheet for the panel on this WaveShare screen and compare the pinout. The display is stuck to the back of the PCB. I am rather worried about pulling them apart in case I damage the LCD display!

Re: Interfacing an LCD display to the Pi

Posted: Tue Jun 19, 2018 12:43 pm
by willharwell
I have three of these that I use: https://www.ebay.com/itm/M-NT68676-2A-H ... 0977522562

Near the bottom of the page you will find a list of supported displays. Before purchasing email them the model number of your display and they'll send you the correct board.

Re: Interfacing an LCD display to the Pi

Posted: Wed Jun 20, 2018 1:52 pm
by FruityNutPi
Thanks. I have contacted them with a request for my LCD display.

Re: Interfacing an LCD display to the Pi

Posted: Thu Jun 21, 2018 10:07 am
by FruityNutPi
They have replied overnight an apparently they can't help me with this display....
Back to the drawing board !
Thanks for the suggestion anyway. I twas worth a try.

BTW, I also tried the display on the controller board that I mentioned earlier that came with the 3.5in display, but, perhaps not surprisingly, it did not work.