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olePigeon

QXGA LCD Panels now cheap ... good enough for variable resolutions?

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One thing I'm having a lot of trouble finding is a generic LVDS/TTL LCD controller board, with the usual VGA/DVI/AV/etc inputs, that can do the following:

  • Arbitrary resolutions and scan rates for the target LCD, programmable by the user not the seller
  • Scaling or pixel-doubling

If anyone has any leads in such a thing I would be incredibly grateful.

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LOL! I suggested checking for a controller board from the PiVerse yesterday, but I was only thinking about looking on eBay. Checking in with what's been going on in the Raspberry Pi community might be a better idea. @Bunsen that may be a good place widen your search. Who knows, if there isn't a board available, somebody might have figured out how to turn a Pi into one?

 

Quick check later:

Pi 4 has a Display Serial Interface (DSI) on board and there's a howto for hooking Pi/DSI up to a panel:

https://core-electronics.com.au/tutorials/how-to-use-a-screen-display-with-raspberry-pi.html

 

Wondering if oddball Mac Video output resolutions/timings might be fed to GPIO, the data massaged on Pi 4 and pushed through the DSI output? Pi might to be able to scale/embed whatever the input resolution/timing in a  might be letterboxed full resolution QXGA (or other) output frame a/o scale it to multiples between input and DSI->LVDS output limitations?

 

Was looking for info on converting DSI to olde schoole LVDS (if necessary) and came up with:

 
WAG here is that Pi4 and a shield or two might become a general purpose converter from any given VGA output to any given panel's LVDS input? Dunno about this stuff, but crazy notions come up and I toss 'em back out, but something along the lines of this might sound like an idea worth researching to somebody?
 
 
 
edit: wondering if ancient LCD outputs from Luggable thru the last non-LVDS PowerBook panel might be handled in the same fashion? [}:)]
 
Edited by Trash80toHP_Mini

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3 hours ago, Bunsen said:

Arbitrary resolutions and scan rates for the target LCD, programmable by the user not the seller

I recently bought a super-cheap LCD/Scaler combo that uses a Realtek-based scaler chip that's ridiculously widespread in the cheap boards. I've done digging on the "RovaTool" software mentioned a lot in this guy's posts and I have been wondering if it's worth trying to tweak it, since its out of the box configuration is less than optimal. I don't have the link handy, but there's actually a tool out there that can program the board without a separate programmer if the board has a VGA port wired according to the reference design. (It can pass SPI through the DDC channel.)

 

That said, these tools are *extremely* user unfriendly, and are mostly for getting the board to work with specific panels. I haven't found anything on how to tweak the input parameters, which is also a thing I'd like to do. It may not be possible with this chip; it seems to be a very TV-centric device.

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...Well I finally received the LCD controller for my IAQX10S from China. Doesn't work. :(

While the backlight lit, nothing displayed on screen, and according to the EDID info the controller is set with a max resolution of 1440x900 (aka typical "we didn't even bother configuring this LCD controller" resolution).

DumpEDID v1.07
Copyright (c) 2006 - 2018 Nir Sofer
Web site: http://www.nirsoft.net
*****************************************************************
Active                   : Yes
Registry Key             : DISPLAY\AGO0001\5&11ec779c&0&UID1048849
Manufacture Week         : 45 / 2013
ManufacturerID           : 61188 (0xEF04)
ProductID                : 1 (0x0001)
Serial Number (Numeric)  : 1129197617 (0x434E3031)
EDID Version             : 1.3
Display Gamma            : 1.97
Image Size               : 81.8 X 107.3 cm (53.1 Inch)
Maximum Image Size       : 30 X 23 cm (14.9 Inch)
Maximum Resolution       : 1440 X 900
Support Standby Mode     : Yes
Support Suspend Mode     : Yes
Support Low-Power Mode   : Yes
Support Default GTF      : No
Digital                  : Yes

Supported Display Modes  :
    1024 X  768  60 Hz
    1280 X  720  60 Hz
    1280 X  720  120 Hz
    1280 X  800  60 Hz
    1280 X  960  60 Hz
    1440 X  900  60 Hz
    1440 X  900  75 Hz
    1280 X 1024  60 Hz
    1280 X 1024  85 Hz
*****************************************************************

I bought it from this AliExpress seller, best stay away from it. :(

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1 hour ago, lameboyadvance said:

I bought it from this AliExpress seller, best stay away from it. :(

Yuck.

 

Something I didn't mention about that cheap-o LCD/Scaler board combo I bought on eBay: the eBay listing I ordered *that* from proclaimed it was "NEW", all-caps. Actually, no, the LCD panel I received with it has the worst burn-in I've ever seen. It looks like it might have been harvested from some sort of in-flight entertainment system or something, no idea because reading Chinese isn't a skill I possess, but if I *could* read Chinese then I'd have no problem whatsoever telling you what was statically displayed on it for probably *years* straight.

 

The seller pretended to be very apologetic and there is a replacement in the mail, but I have this feeling that when it arrives and I discover it's just as ruined as the last one I'll be filing an "Item not as described". Watch yourselves out there, kids.

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