Thread: Successful LVDS LCD installations?

Here's an example of the LVDS pinouts required for the motherboard (Commell LV-671) and LCD (EVD084S01-DT from eVisiondisplays.com, aka AUO B084SN01 w/enhancements) that I have chosen for my WRX CarPC project.


The document shows three things:

1. The LCD Type number table, used to set the LCD Type in the BIOS.
2. The LVDS connector pinouts on the motherboard.
3. The LVDS pinouts on the LCD panel.

The LCD I chose is an 18-bit panel at 800x600, and is a single-channel model, so the appropriate LCD Type setting in the BIOS would be number 2, which is highlighted in Bold.

If the LCD was different, I would have to pick a different type, such as a 1024x768 24-bit Single Channel panel - the appropriate LCD Type would be 8.

What's the difference between an 18-bit panel and a 24-bit panel?

An 18-bit panel can display about 262K colors, and a 24-bit panel can display 16 Million. Most smaller LVDS LCD panels will only be 18-bit, as most 24-bit panels are larger and have a higher resolution.


For the 18-bit 800x600 single-channel LCD I chose, the pins I would need to connect to on the motherboard are highlighted in bold - there are a total of 18 pins, to match the 18 of 20 pins on the LCD panel connector.

The LVDS data is transmitted on the ATX0-2 +/- pairs, and each pair carries 6-bit's worth of data, so for an 18-bit single-channel panel, I would need to use the first three ATX pairs. For a 24-bit single-channel, I would need to use the first 4 ATX pairs.

You may notice similar pairs named BTX0-3 - those are for the 2nd channel, if you needed a dual-channel connection. For an 18-bit dual-channel, you would use ATX0-2 (3 pairs), and BTX0-2 (3 pairs). For 24-bit dual-channel, you would use ATX0-3 (4 pairs) and BTX0-3 (4 pairs).


The transmitted data is kept in sync by the ATXCK (clock) pairs - for a dual channel LCD, you would use both clocks, and possibly the PANELCLK and PANELDATA pins.


One remaining thing I have to verify is the polarity of the +/- pairs.

That is, whether the - on one end goes to the + on the other, or whether it's a same-to-same connection, like - to - and + to +.

I think it's same-to-same, but I have to verify that.

Originally Posted by Yuriy

Hehe, well, I got lucky and actually extended my laptop cable to about 2 meters (6 feet).
Works great with just a little interference (barely noticable).
That's some good info though, the LVDS sure sound like an option. You'd need pinouts and connectors tho, as I would guess..

Actually, this had me thinking...

Do you know what the model number of the LCD panel is?

And what kind of cabling/wire did you use?


There's a possibility that your LCD panel is LVDS.. and if you extended it to 6 feet with little interference, that's a good sign.

Originally Posted by Yuriy

The LCD is Toshiba LTM12C263, it came with the Compaq LTE 5300 laptop (all 5xxx series have the same connectors except for 5250).

This LCD model is not LVDS, but TTL/CMOS - I'm amazed you managed to get a good signal with a cable that long, as everything I've read has indicated otherwise.

Pinouts found here:
http://physio.phys.szote.u-szeged.hu.../ltm12c263.htm

The first two columns show the pins for the LCD-side connector.

The signals R0-R5, G0-G5, and B0-B5 indicate that this is a 18-bit (6+6+6) TTL/CMOS panel.

Originally Posted by Yuriy

I do not have the pinout, but it's approximately 24 pins in a row (similar to the ones you have) on the LCD side and 2 rows of approx. 12 pins on the motherboard side. But! The same LCD used on the Armada laptop only has about 6-8 wires (excluding the inverter) that connect it to the motherboard!

Oh yeah, the one in the Armada is a slightly different LCD with the LTM12C283 and it has a resolution of 1024x768 instead of 800x600 that my LCDs have. The connectors that go into the LCD itself are exactly the same.
http://www.mp3car.com/vbulletin/atta...achmentid=3462

The specs linked above for the *63 LCD say 30 pins, so ~26 pins might be right..

Originally Posted by Yuriy

One more thing I noticed is that when you connect an LCD with a lower resolution (I have some with 640x480) to a laptop that outputs 800x600 you will still get the image but it will be moved 160 pixels to the right and 120 down, just like the black "frame" you always seem to notice around higher resolution screens running at lower res then native. The image was chopped off but otherwise was pretty clear. I bet it could be fixed with the right software.

I have a few thoughts on that - it might be solved with using only the Least Significant Bits of each channel, like R0-R4 instead of R0-R5, for example, but I think that has more to do with color depth.. maybe..

Got any part numbers for those 640x480 LCD's?
I'll see if I can find specs and take a look..

Originally Posted by Yuriy

Anyway, you got me thinking too, seems like we are one step closer to connecting a laptop LCD to a PC
I am thinking about sending you one of my LCDs and see if you can connect it, and then if you succeed we would all benefit from it

Sure!

PM or e-mail me a list of the LCD's you've got, and part numbers, and we'll see.

I do have an old Compaq Presario laptop with a perfectly working LCD, so I'll see if I can dig that out and check the specs on it.. I think it's a 14.1", but if it's LVDS, it'll be good for testing.

In any case, I probably won't have my motherboard for another month or two, depending on my free spending cash at the time..

Have any of you managed to find an LCD comparable to the Xenarc at a reasonable price? 7" 800x600.