Need your comment on a portable D display connection design.

einzeln · ‎05-15-2012

I need to design a TX/RX pair which functions like a HDMI 1.4 3D, for a proprietary HUD. The source signals are 2 distinct TFT output in RGB, and the sinks are also two separate TFTs, and a stereo audio also need to be transferred in the same cable, but is on a lower priority.

The purpose is to reduce pin count of the cable connector.

LVDS signals on Xilinx spartan 6 could be transferred in meaning as GTP(PCIe) or SelectIO(TM) through IOB. The bandwidth estimation is about 600Mb/s in XVGA(single line).

Should i build a SerDes to bundle DVI(HDMI)signal in PCIe, or build something from scratch.

Thanks for your reading and your comment is valuable.

eteam00 · ‎07-21-2009

It would be good if you could focus your interests a bit more. Your initial post spans so many technologies and buzzwords, your "problem description" seems vague and 'random', and it is unclear what you are trying to accomplish.

-- Bob Elkind

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gszakacs · ‎08-14-2007

It's not clear to me how you want to use this link. Are you saying that you'll

have a Spartan 6 at each end of the link? How far does it need to run?

Someting like a headset cable (maybe 60cm?)

I would not suggest using PCIe, just because of the protocol overhead. Something

like Fiber Channel or serial FPDP would be simpler if you decide to use a GTP.

On the other hand, if each TFT only needs about 600 Mbps, then a couple pairs of

LVDS would be enough. 300 MHz DDR should be easy enough to accomplish

with general purpose LVDS I/O. One pair would transfer up to 600 Mbps using

whatever protocol you add to it. The tough part with general purpose LVDS is

clock recovery. You could use another LVDS pair to send a clock ala Channel-Link

(very common usage for industrial video - look up Camera Link). That clock could

also serve as the word frame if the cable skew is low enough. That's really the

tough part about Camera Link cabling and the reason it needs to be so thick.

Another odea may be to use one of the newer industrial video standards like

CoaxPress.

-- Gabor

einzeln · ‎05-15-2012

i'm building a embedded device running linux by a ARM SOC chip, nothing fancy, except the display is not a conventional TFT LCD which drived by pixcel, line, and frame sync clock and 3*8bit RGB color signal, but TWO, to implement stereo display (actually two small OLED fitting in a gaugle).

The idea is to drive this Head-Up Display over a cable, of course 3D HDMI is an option, but implement it is such a huge task and i don't know something handy, so i need to do it somehow quirky, to reduce the wire required for the hud.

my idea is roughly to put two fpgas on each side of the cable, and convert raw LCD drive signal into DVI or something like to reduce wire count.

thank you for your advice of posting.

eteam00 · ‎07-21-2009

Some thoughts to consider:

LCDs are rarely 8-bit (per R|G|B) devices. Almost always they are 6-bit, using temporal dithering to approximate finer tonal gradations.

Ignore the LCD frame rate. What frame rate is needed for your image content? For example, cinema is almost always captured at ~24FPS, but displayed at higher frame rates. Do you have motion content which demands a higher frame rate than 24FPS?

Consider other data compression techniques, such as temporal data compression, transmitting frame-to-frame differences.

DVI/HDMI/VGA signal formats all transmit H and V blanking intervals. Audio is embedded in the blanking intervals, but doesn't come close to filling up the data space. You can reduce bit rate considerably by not bothering to send H,V blanking interval data.

DVI/HDMI is both a signal format and an electrical interface specification. You should distinguish these aspects when you reference DVI/HDMI. For example, both HDMI and DVI-D use TMDS-33 signal levels for video -- plus I2C in the out-of-band channel for EDID.

-- Bob Elkind

SIGNATURE:
README for newbies is here: http://forums.xilinx.com/t5/New-Users-Forum/README-first-Help-for-new-users/td-p/219369

Summary:
1. Read the manual or user guide. Have you read the manual? Can you find the manual?
2. Search the forums (and search the web) for similar topics.
3. Do not post the same question on multiple forums.
4. Do not post a new topic or question on someone else's thread, start a new thread!
5. Students: Copying code is not the same as learning to design.
6 "It does not work" is not a question which can be answered. Provide useful details (with webpage, datasheet links, please).
7. You are not charged extra fees for comments in your code.
8. I am not paid for forum posts. If I write a good post, then I have been good for nothing.

ccon67 · ‎01-21-2011

If I heard you right you may want to reduce the wire counts.... referenced to the already exist 3D -HDMI ?

What is the number of wires you think may reduce to ?

Sound like you gonna invent something better than 3D -HDMI ?

einzeln · ‎05-15-2012

My data sheet has specified RGB 4:4:4 is a 8*3 input.

Thanks for your advice. After searching for solutions I found a micro-USB port physical compatible interface named MHL, it's a DVI aggregation ideal for my application.