Casio 5 inch LCD (from gamecube screen)

[ptm]

Hi guys. I have this Casio LCD which I got for dirt cheap (just a couple bucks). Maybe beyond the scope of what most people on this forum do, but I figured I'd give you guys a try anyway.

I've got a programmable logic device and a RAM chip hooked up to this thing acting as a framebuffer, so I can do whatever I want with it rather than just hooking it up to a gutted console that already has video generation circuitry onboard.
I'm pretty sure I've got the sync and memory timing right at this point, but the colors are quite dark.
I copied the binary-weighted DAC from a working VGA circuit (http://digilentinc.com/Products/Detail. ... Prod=NXVGA" onclick="window.open(this.href);return false;), which assumes 75 ohm termination and roughly 0.7V for max signal. I'm pretty sure that should be correct.

Does anybody happen to know why the colors might be so dark?

Cheers,

ptm

[ptm]

Well, in case anybody is interested, it seems to be that the analog inputs on this thing are not actually 0.7V peak to peak.
I looked at a datasheet of a very similar module (couldn't find one for this exact one) and the values were 0.7V minimum, 1.4 typical, and 2.0 max.
So I halved all of my resistor values on the DAC to roughly double the ouput, and got a considerably brighter picture.

Cheers.. I'll keep lurking here from time to time probably.

ptm

[andrewdorsey]

Can you post a picture?