On 3/16/06, James Richard Tyrer <[EMAIL PROTECTED]> wrote:
> Getting back to the RAMDAC.
>
> I can't find any that are not intended for TV use -- although I might
> look some more if I have time.
>
> So, if we want to implement this, I would suggest that we have the SRAM
> in the FPGA.  Therefore, the only circuit requirement would be that ALL
> the DAC inputs be connected to the FPGA then the implementation could be
>   done however we want by just changing the FPGA programing.

I guess I forgot to mention this.  The FPGA has gobs of RAM in it. 
There will definitely be three LUTs for video.  There's not a lot we
can do to get MORE than 8 bits out, although we can temporally
modulate it to trick the eye into seeing more shades.

>
> Do consider using the less expensive DAC which is made for this specific
> use and has RS-170 buffers already built in.

The 330MHz DAC isn't that bad, is it?  We're not populating the highspeed ones.

> Note that if we do go with the design, I should point out that the black
> voltage for RS-170 is NOT 0 volts but rather 0.095 volts so a slight
> bias is needed for the video out buffers.  Perhaps this would be enough
> so that they could be run with single supply if we used a different amp
> that was designed for single supply.

Isn't there only an amp for the highspeed DAC?  Still, it's important
that we get this right too.
_______________________________________________
Open-graphics mailing list
[email protected]
http://lists.duskglow.com/mailman/listinfo/open-graphics
List service provided by Duskglow Consulting, LLC (www.duskglow.com)

Reply via email to