Spartan-3 LVDS driving TFT LCD panel..?

(sometimes called Panel-link

up to - I saw a mention

immediately see any

Look at

It's not for TFT panels but for their TX side, they serialize 10 bits by using a 5x clock and DDR flips flops with a differential output.

but LVDS needs 2.5v,

useful degree

Well, on lower end board, the trace might not be routed as differential anyway. The Avnet spartan 3 board (the PCI one) I have has 4 LVDS pairs connected on 2.5v rail.

That's definitly something I'd like to do. I might try it soon with an old laptop scree if I find the doc for it.

Sylvain

(sometimes called Panel-link

up to - I saw a mention

immediately see any

but LVDS needs 2.5v,

useful degree

Funny you should mention this - I am working on exactly this at work right now.

It's not working right now, but the basics are in place. clock runs and I see data coming out of the fpga, but I think I might be shifting bits in the wrong place. Panel stuff is annoying in that the data streams are organized in 7-bit chunks which means you have to do some trickery to do shifting via the DDR registers.

The DDR trick is nice, otherwise you end up doing a fair bit of monkeying with RLOC attributes if you want to run an s3 -4 speed grade part at 200+ Mhz.

Our board has a selectable 2.5V/3.3V bank for doing either LVTTL or LVDS panel stuff.

I assume you know about the TTL to LVDS chips made for this from National and others?

(sometimes called Panel-link

up to - I saw a mention

immediately see any

but LVDS needs 2.5v,

any useful degree

What frequency/display format are you aiming for ?

Yes - I bought a couple to play with after messing with a ttl (parallel) style interface, but I was wondering how possible it would be without..

(sometimes called Panel-link

up to - I saw a mention

immediately see any

but LVDS needs 2.5v,

any useful degree

TFT panel docs are a bit scarce but from what I've seen, they are all very similar to each other within any given resolution. If you have the whole laptop lid, you will have the cable/flexi which will help identify the connections. Here are some links to tft pinouts and data I found a while ago. Most concern ttl-style panels but even the LVDS ones are based on this, so give a starting point for experimenting with timings etc. Some LVDS panels have an identifiable LVDS-to-TTL converter chip, so the pinouts can be derived by beeping out the pins.

We should have something for you in Raggedstone1 when it launches if you want to play with this.

John Adair Enterpoint Ltd. - Home of Broaddown2. The Ultimate Spartan3 Development Board.