Re: New vector hardware

>Don't know if anybody read all of my previous post, but I was inquiring
>about the possibility of getting back to figuring out what it would take to
>build a vector generator card that we could slip into a computer.
>
>I remember there were some concerns on vector length vs. intensity and what
>the best way was to draw diagonal (or off diagonal) lines.

I was doing this a couple years ago. What I had was two 12-bit paralle
DACs, fed by two CPLDs. The CPLD's took a fixed-point decimal rise/run
value and a length and then added the value into large(r) accumulators which
fed the higher order bits to the DACs. The draw rate was constant and
brightness was predictable. A separate set of latches made a 15 bit (5R,
5G, 5B) color value. In front of the CPLD's were two NEC field memories (a
dual-port video memory) with independant read and write ports. The PC would
write a list of lines and their colors (a display list) to the memory, then
flip a "go" bit. The CPLD's would then take off, reading the memories and
interpreting the displaylist and making the DACs and color latches do their
thing.

The problems were:

1) It was ISA, and Al would guilt me constantly about not doing PCI for the
Mac people. ;-)
2) The field memories for $15/ea and were obsolete.

If I were to try it again, I'd just use a PLX chip for the PIC interface,
and then put a XCS05 or XCS10 FPGA on the other side. The FPGA would hold
the display list and drive the DACs and latch the colors the same as the
CPLD's/'273s did before, but in one component.

There's probably 1000+ different ways to do it-- I just liked the all
digital approach instead of a Cinemat or Atari AVG-like system.

(For something "non-PC" driven, a Sega G-80 Vector Generator with more
precision in an FPGA with linear-scaling added to the outputs would be
really cool to program on. Not sure how useful it'd be for emulation.)

-Clay
_________________________________________________________________________
Get Your Private, Free E-mail from MSN Hotmail at http://www.hotmail.com.

Share information about yourself, create your own public profile at
http://profiles.msn.com.

---------------------------------------------------------------------------
** To UNSUBSCRIBE from vectorlist, send a message with "UNSUBSCRIBE" in the
** message body to vectorlist-request@synthcom.com. Please direct other
** questions, comments, or problems to neil@synthcom.com.
Received on Wed Oct 11 17:00:06 2000