Re: Vector Games - Theory of operation??

Mark C. Spaeth wrote:
> ed_h <ehenciak@xxxxxxxxx> wrote:
> : Just curious,
> :
> : How is emulation "crap"? I recently played the Williams multigame
> : at a rest area in Ohio and was amazed at how perfect gameplay both
> : looked and sounded. Moreover, the horizontal Sinistar was sweet (try
> : pulling that off in hardware).
>
> Yeah, sinistar is just SO fun without a 49-way stick.

It is...it's fine. Played both "real" and "emulated" recently and
gameplay is pretty much the same. True the 49-way joystick adds a
little, but the fact that many other games are on the PCB makes the
overall package that much more fun.

>
> : Also, the fpgaarcade version of Asteroids Deluxe is nothing short of
> : amazing. Try loading it up and playing it on a VGA monitor. Sound is
> : virtually dead on using a simple one bit dac.
>
> All high end audio uses 1 bit dacs and oversampling for the perfect
> linearity, since audio is so ridiculously low frequency. Try having
> a clue.
>

WOW! Impressive, big words like linearity...cool! And insults like
"try having a clue"....wow, that's good!!! I mean, an insult derived
from the 1980s "Get a clue" here on a message board that is geared
towards 80s arcade games...did you plan that, cause I found that to be
funny...really funny.

As always, the condescending attitude you have displayed over the years
clearly demonstrates a complete insecurity from which you suffer. I
wish you well in your career...you'll really need to fix that problem
you have if you want to achieve any lofty goals someone like you is
capable of achieving.

What I was getting at is that the DAC is pretty much embedded in the
FPGA. All you need to do is run the simple 8-bit pulse width modulated
value thru a simple low pass filter and you get very good to
outstanding "8-bit gaming quality" audio for pennies. You know
that....others may not.

All you need is an 8 bit counter, an 8 bit comparitor, and some
passives. Some people wishing to make their own PCBs might make the
mistake of laying down a bunch of 8 bit DACs and subsequent mixing
circuitry when most of this can be done for a lot less in a PLD. A
"reproduction" of the Sega Star Trek Universal Audio board would come
to mind! Someone using old parts might feel the need to lay down a
motherload of obscure, parallel, 8 bit DACs on a PCB when the same
results can be achieved using modern methods at a much lower cost.

"High end" audio is done using other conversion techniques (again, as
YOU know, but the rest of us mortals may not know that) that, in the
end, are one bit DACs similar in functionaly to what I describe.
However, using the simple technique one may use in an FPGA, you'd need
a clock rate of 3.22THz (not a typo) to reproduce 24 bit audio @
192KHz. Again, you obviously know this....however, others may not.

In my experience, the best, low area DAC you're getting out of todays
FPGAs is about 13 bits of resolution @ 24KHz assuming you have an
FPGA/PLD that is capable of runnning at 200MHz. I whipped together a
simple Nios-MP3-player-in-an-FPGA and that was the best I could do if
memory serves.

> In any case. reimplementing hardware with accurate CPU cores in an FPGA
> isn't emulation, now is it?
>

Um, yes, it is 'hardware' emulation. What is the difference between
using one processor to emulate another processor and dropping a
cycle-for-cycle accurate core into programmable logic? Nothing as far
as I am concerned...therefore, they are both emulation solutions.
That's the point I am getting at. If all the ones and zeroes line up
as they should, who the hell cares how they got there?!?!?!

> : Quite frankly, I think making PCBs with 30 year old parts on them
> : and pawning them off as new is "crap".
>
> Who's using 30 year old parts? Just because TTL part EXISTED 30 years
> ago doesn't mean the parts being used are 30 years old.
>

What I was getting at is why would one design something new, today,
with TTL logic, when the same design could be made using newer
technology at a fraction of the cost. I know that a part that has been
around for 30 years was more than likely fabricated recently (except
for those damn UDN7180As I can never find at a reasonable cost)!

Suppose I wanted to do a run of new Asteroids boards. I'd be nuts to
lay down the 30 year old parts and make the (now) insanely large PCB.
For small runs or homebrew projects where cost is not an issue, I
totally understand. If you are trying to reproduce the PCB much like
one reproduces game artwork, I understand!

However, making something new where the primary goal is functionality
and in some relativly high quantity (like 100 pieces), why would you
use old, thru-hole TTL parts??? Once you add up the time it takes to
assemble each PCB, the size of the PCB, and procurement of virtually
obselete parts, your cost goes through the roof. Toady, even in low
quantity, I can have the boards assembled and tested automatically at a
cost far less than doing it manually assuming you charge money for your
time.

> : There are better solutions at lower cost using modern technology.
> : Dismissing emulation of classics as "crap" is rather, well, stupid in
> : my opinion. Any PCB you get is a black box stuffed to the brim with
> : ways to mutate ones and zeroes. Aside from collectors, who the hell
> : cares if you are playing the game on either the original or replacement
> : medium.
>
> ...because the original can be repaired, and black box emulation crap
> is throwaway when it dies.
>

So what? The cost to have a typical PCB repaired is around $100 +
parts. For $400 I get the same "virtual" PCB with more games on it.
So what if I cannot repair it! Odds are the more modern board is going
to cost far less to manufacture and will probably outlast any NMOS or
TTL based ICs out there!

Moreover, why does it need to be thrown away...plenty of places out
there will fix SMT boards at a very reasonable price....probably for
far less than the cost of a typical PCB repair! If the part is BGA you
probably run into cost issues for repair, but give it a few years and I
assure you it'll drop down to a reasonable price.

Look, from a purist, collector standpoint, I understand your "crap"
argument. There is a huge cost associated with that though and I happen
to believe that newer technology solves the cost issue. Emulating the
game provides identical results at a fraction of the cost. From a
technolgy standpoint, calling it "crap" is rather lame. A lot of hard
work goes into those products and, quite frankly, who the hell else is
making replacement PCBs? I know you do Berzerk/Frenzy MPU replacements
and there are 5 or 6 flavors of replacement Bally pinball MPUs...but
for video games, you are SOL if you are looking for a more reliable
Williams Defender PCB and the like.

You can fire away with all the insults you'd like, but at the end of
the day, nobody is going to pay what it would take to "reproduce"
Asteroids or any other 80s PCB for that matter.

Just curious, what would people be willing to pay for a "new" Asteroids
board that is not original-looking (in terms of the PCB) in any way,
but plays, acts, sounds, and behaves exactly like one?

Ed


> --
> Mark Spaeth mspaeth@xxxxxxxxxxx
> 50 Vassar St., #38.265 mspaeth@xxxxxxx
> Cambridge, MA 02139
> (617) 452-2354 http://rgvac.978.org/~mspaeth

.

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