Re: ISA Vector card already done...

 Look, I've only been following this discussion in a very cursory manner,
but there is NO WAY you need 144 MHz anything to generate the vector stuff
for one of these games. Consider: the game boards have roughly 10 MHz
clocks... these boards use D/As.. and slow-ass ram, etc etc... so I guess
I better read these designs being flung around a little closer because
that 144 MHz rate is ridiculous!

                                Just spouting off,
                                Mitch

On Wed, 25 Mar 1998, Zonn wrote:

> On Tue, 24 Mar 1998 17:02:56 -0800, Clay Cowgill <ClayC@diamondmm.com> wrote:
>
> >...well, sorta. ;-)
> >
> >http://www.rtsys.com/rt02003.htm
> >
> >Has basically what I've been talking about. (an ADSP-2181 I/O mapped
> >into a PC ISA slot.) They have a connector for hooking up CODECs for
> >two-channel audio. I was going to buy one until I saw that the cards
> >are $500. :-( Too rich for my blood. I should be able to do one for
> >1/4th that much, maybe less...
> >
> >It turns out that Eric Crabill (haven't heard from him in a LONG time)
> >did kinda-sort the same thing a couple years back in school. He used an
> >ADSP-2111 and a couple 16-bit D/A's hooked up to an Amiga. (The 2111
> >has a pre-cursor of the 2181's IDMA port on it.) Eric sent me his source
> >code for drawing lines (which he got from an older Analog Devices book)
> >so the project just got simpler. ;-)
> >
> >I currently like the AD7249 D/A for the output stage. Dual Voltage
> >output, 12-bit serial, glueless interface to the DSP. Kinda spendy ($18
> >singles), but I'm in "screw the price, make it *DO* something" mode
> >now...
>
> And the serial update is fast enough? I remember looking at serial D/A and for
> a 6mhz update needed for an asteroids speed display (all from memory -- maybe it
> was 3mhz?) for a dual channel 12 bit port you needed a 144mhz data clock going
> into the thing. Does the AD7249 really operate that fast? Or am I missing
> something -- which could easily be the case...
>
> -Zonn
>
> <><><><><><><><><><><><><><><><><><><><><><><><><><><><
>
> ------ ___ Member of A.A.C.S.:
> |---- | ( ) Association for Artistically
> / / ( () ) Challenged Signatures
> / / //\\ // (__)
> / ---/ // \\ //\\ // zonn @ zonn . com
> -------| // \\/
>
Received on Wed Mar 25 13:05:23 1998