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

Quote: 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

Quote: 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...

Lucky13ESP · 03-27-2008, 02:47 PM

This page is from the user manual of the mobo. Available Headers

They appear to be different from the LVDS header.

benedums · 03-27-2008, 02:52 PM

what are the pin assignments of CN23 & CN18?

Lucky13ESP · 03-27-2008, 02:59 PM

Header	Pin #	Description
CN23	1	VDDSAFE5 (+5v output)
CN23	2	VDDSAFE5 (+5v output)
CN23	3	GND
CN23	4	GND
CN23	5	VDDSAFE3 (+3.3v output)
CN23	6	VDDSAFE3 (+3.3v output)
CN23	7	NC
CN23	8	GND
CN23	9	R00
CN23	10	R10
CN23	11	R01
CN23	12	R11
CN23	13	R02
CN23	14	R12
CN23	15	R03
CN23	16	R13
CN23	17	R04
CN23	18	R14
CN23	19	R05
CN23	20	R15
CN23	21	G00
CN23	22	G10
CN23	23	G01
CN23	24	G11
CN23	25	G02
CN23	26	G12
CN23	27	G03
CN23	28	G13
CN23	29	G04
CN23	30	G14
CN23	31	G05
CN23	32	G15
CN23	33	GND
CN23	34	GND
CN23	35	SHFCLK
CN23	36	FLM
CN23	37	M/DE
CN23	38	LP
CN23	39	NC
CN23	40	ENAVEE
CN18	1	GND
CN18	2	GND
CN18	3	B00
CN18	4	B10
CN18	5	B01
CN18	6	B11
CN18	7	B02
CN18	8	B12
CN18	9	B03
CN18	10	B13
CN18	11	B04
CN18	12	B14
CN18	13	B05
CN18	14	B15
CN18	15	GND
CN18	16	GND
CN18	17	NC
CN18	18	NC
CN18	19	NC
CN18	20	NC

Lucky13ESP · 03-27-2008, 03:10 PM

In the case that this is a 36 bit TTL output i've started matching up pinouts

I'm matching like so:

RA0 = R00
RA1 = R01

RB0 = R10
RB1 = R11

now for the trick part. I have these labels left over

On the LCD
CK (Dot Clock?)
Hsync (Latch Pulse?)
Vsync (First Line Marker?)
OHP-
ENAB

On the mobo
SHFCLK (Shift Clock?)
FLM (First Line Marker?)
M/DE (Display Enable?)
LP (Latch Pulse?)
ENAVEE

Let the matching game begin

Again, thanks for the help, I'm learning, albeit slowly

benedums · 03-27-2008, 03:56 PM

So is that from a motherboard or a controller board?

It looks like they split up the TTL interface between two connectors CN23 & CN18 which is a bit odd... none the less since the LCD is +5V you will not need to use the +3.3V... The ENAB on the LCD is probably the ENAVEE, CK could be SHFCLK, not sure where the Hsync and Vsync will mate to on the controller. and NC = No Connect...

I would be very surprised if this worked and didn't fry the controller or the LCD or both, so tread carefully.

It's best to find a controller that you know is compatible with the LCD...

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