LCD connection

The datasheet maybe mentioned the panel had VGA _resolution_ (640x480), but the panel is a 18(?)-bit TFT LCD, which requires parallel digital colour signals for each pixel. Get a different panel. Robb.

Or work out how to do video A/D work and timing synchronistaion. Unless the panel already has a more normal connector via a cable, the panel probably has a tiny connector that will provide more problems than the electronics.

Too many panels from the same manufacturer have different connectors on different models, for the same type of input.

-- Paul Carpenter | snipped-for-privacy@pcserv.demon.co.uk Main Site GNU H8 & mailing list info. For those web sites you hate.

What is the SBC? Does it have a parallel LCD output as well?

single

TFT

It is a SBC based on national geod GX1 processor with CS5530A companion chip. The CS5530A does have 18 bits flat pannel support. But looks like the board didn't provide connector for those pins.

This is a good idea.

don't quite understand what you meant here.

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pins,

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Oh boy. I know the chipset very well. Well, first have a look for unpopulated connectors - maybe they did run the lines to pads someplace..

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I tried check the connectors, but the board is 7 layer PCB, it's hard to see where it runs to . Do you think it's feasible that if i build a A/D converter to convert VGA signal into 18 bits digital ?

Basically LCD panels especially for graphics, are mainly laptop/mobile applications orientated, made for short periods of time. Then new models come out and my experience with several manufacturers is they all claim to use standard connectors, but it depends on what the standard was when the panel came out.

I have seen many manafacturers, with different models at same resolution have completely different connectors to connect your 18bit digital signals upto.

These connectors are nearly always 0.5mm pitch or LESS!

The amount of adapter cable designs I have had to go through is unbelievable. Quite often in a short period of time. I tend to design interfaces for digital interface outputs that use a 0.1" connector then adapter cable to the particular panel in use at the time.

If you cannot find the digital outputs or where to add the connector to get the digital outputs, the YES you will need a circuit with a TRIPLE A/D. Also you will need some form of circuit to control the digitisation and clock locking to digitise the signal.

I would suggest you think about the evaluation board for the Averlogic AL300 (digital video to LCD controller) or even just their AL875 (triple A/D) Both are quite cheap and as soon as you move away from VGA resolution, you can sometimes have problems with sync polarity interfacing.

Last time I used that panel was four years ago and it is relatively easy to get going, watch for getting your clock right and enable signal correct. I was doing RGB 50Hz and standards conversion in real time to the LCD, I doubt you will have the standards conversion issue.

Hi paul: Thank you for the input. yesterday I was looking for triple 6 bits A/D, but turned out nobody has it instock (or nobody would buy it). looks like I have to do some PCB design, big challenge for me. Too bad the board designer didn't populate the FP support in cs5530A chip. sigh!

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correct.

There's a lot more to it than that. You need to synthesize a dot clock, for one thing. And the analog issues involved are definitely non-trivial. If you're an analog guru and have positively shamanic powers of hand-prototyping high-speed analog circuits, maybe you can consider it.

I would suggest it is much easier to spend $120 on eBay on a 14" LCD monitor with analog VGA inputs.

you could look for one of the chips they use in LCD monitors to do the analog VGA to LCD conversion. IIRC they are fairly simple and cheap, but you would probably have to do a PCB design. Of course you could just buy an LCD monitor and rip the board and panel out and mount it how you like if this is just onesy-twosy stuff.