LVDS cable help

**Lucky13ESP** · 03-27-2008, 12:51 PM

I've got a bare panel (Sharp LQ10PX22) and a board Advantech PCM-9577 that both support LVDS. The Sharp monitor specifies "18(6xRGB)x2 bit parrallel data signals, four kinds of timing signals, and +5V DC supply voltage for TFT-LCD panel driving." The Advantech board's data sheet states it "supports 2 Channel (2 x 18bit) LVDS interface."

LCD Pinout
Mobo Pinout

First question, are these compatible?
Second question, what sort of cable do I use to connect it?

The sharp monitor uses a Japan Aviation Electronics Industry Ltd KX14-80K2D receptacle and the Advantech board uses a Hirose DF13A-20DP-1.25V receptacle. I think I've done all I can do

and now I'm in need of your expertise. Let me know if you need anything other specs (I found most of the data sheets). Thanks in advance.

**Rob Withey** · 03-27-2008, 01:45 PM

That LCD pinout doesn't look like LVDS. Why do you think it is LVDS?

**turbocad6** · 03-27-2008, 02:07 PM

yeah, that is not lvds display pinout, probably ttl I think...

**Lucky13ESP** · 03-27-2008, 02:11 PM

I guess I just kind of assumed it was since it matched the 2x18 of the LVDS of the mainboard. That is why I'm asking the community here which knows a lot more than me. Here is a link to the outputs available (i'm not including vga but it has a header too):

Available headers

**Rob Withey** · 03-27-2008, 02:13 PM

It can be made to work. I'm running an 18 bit TTL panel from an LVDS output using a Advantech PCM3540 LVDS receiver to interface it.

**Lucky13ESP** · 03-27-2008, 02:14 PM

Ok, if you two agree it isn't LVDS then it must not be

I think that explains why I couldn't figure out the conversion between the two pinouts. I'll take a look and see what I can figure out now. I'm sure I'll have more questions for you including what is the max length of a TTL "cable bundle" Thanks so much for your quick responses.

**Lucky13ESP** · 03-27-2008, 02:15 PM

Originally Posted by Rob Withey

It can be made to work. I'm running an 18 bit TTL panel from an LVDS output using a Advantech PCM3540 LVDS receiver to interface it.

Would it be better to the route described above or straight TTL to TTL. I'm guessing the straight shot would be best but I'll wait for the gurus to weigh in.

**benedums** · 03-27-2008, 02:19 PM

That LCD pin-out is most likely an 18bit TTL, at least that's what the signals would suggest.

If that's the case the the LCD and Controller would not be compatible.
The controller's pin-out is LVDS (Low Voltage Differential Signal).

You would need a controller that has an 18bit TTL output (to drive the LCD) and whatever input you are supplying from your PC (analog RGB (15-pin D-sub), DVI, or LVDS from your mother board).
The controller also has to support the native resolution of the LCD (the 18bit TTL output has to match the LCD resolution which is 1024x768 for the LQ10PX22).

There are two main types of display interfaces, LVDS and TTL. There are a few threads on here that describe the difference between the two if you're interested.

**Lucky13ESP** · 03-27-2008, 02:25 PM

Thanks for the info benedums.

I'm almost positive my board supports TTL as it has a pinout table that includes diagrams for:
16-bit DSTN
24-bit DSTN
18-bit TFT
24-bit TFT
36-bit TFT

In this case I'm guessing the TFT is equivalent to TTL. Is this a mistake on my part?

I'll defer to you guys again but I do believe my display is 36-bit as it includes RA(0-5) and RB(0-5) as well as GA, GB, BA, and BB. I'm just guessing here but 6x6 = 36 bit? Thanks again for all the help.

**benedums** · 03-27-2008, 02:36 PM

Originally Posted by Lucky13ESP

Thanks for the info benedums.

I'm almost positive my board supports TTL as it has a pinout table that includes diagrams for:
16-bit DSTN
24-bit DSTN
18-bit TFT
24-bit TFT
36-bit TFT

In this case I'm guessing the TFT is equivalent to TTL. Is this a mistake on my part?

TFT is the type of LCD (Thin Film Transistor) where TTL is the interface.
So TFT is not equal to TTL...

Most "new" motherboards that support LCD's (TFT, DSTN) do so with an LVDS interface, since that type of cable is less susceptible to EMI interference (TTL is more susceptible to interference).

There are several different formats of LVDS and TTL, each might include 16-bit thru 36-bit.
18-bit LVDS is not compatible with 18-bit TTL without a controller to convert it.

So it's likely that your MB only "directly" supports LVDS panels, unless you have a TTL connector on it, it probably only supports LVDS. Hence the need for a controller to convert the LVDS to TTL...