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Re: RFC : SOME IDEAS FOR THE APPLE II FPGA'ers

mdj wrote:

Michael J. Mahon wrote:



Ack!  I'm sorry to hear that, because I've had a Checkmate for years,
and have been thinking about trying out an RGB monitor with it.  ;-(



As I recall, back in the day Applied Engineering had a patent on the
technique they used in the RamWorks to avoid the screen flicker, and
were obviously unprepared to license it for a reasonable amount.


When, exactly, does the flicker occur?  When the computer switches
to another RAM bank?


Possible--but surely you aren't worried about scarcity or durability
of 74LS chips...



No. PALS, GALS and ASICS on the other hand...


I guess that's where I think that reverse-engineering is quite a
viable path to replacement, and could be done piecemeal as needed.

However, I do concede that this would maintain a "chip sprawl" that
is quite unnecessary and needlessly confining.  I get your point.


When some preservation solution becomes necessary (and it probably
won't in my lifetime), there will be even better tools and techniques,
and the solution will be both simpler and more elegant than it would
be this year.



Oh sure, but by then all of us will have expired as well ;-) Seems to
me it would be good to contribute to the legacy our own ideas and
improvements, otherwise they may be forever lost.



Ironically, it basically uses an FPGA!  ;-)


(As Mark noted, my typing got ahead of my brain on this one--
I should have just typed "programmable logic". ;-)


That, is exactly my point.


But the semiconductor world we live in practically predestines
"overkill" in solutions.  The simplest programmable chips are
very complex compared to the needs of most peripheral cards.

Before long, we'll have programmable-universal 74-series DIPs
because it will be cheaper than stocking a lot of SSI chips!  ;-)

Computing the "intrinsic efficiency" of an implementation based
on transistor wasteage is going to be quite hard to justify for
any older system.

BTW, I do see where you're coming from, and I respect what you
want to do.  I'm just worried that all that I love best about the
Apple II will disappear in the process, and what will result is
just a "hardware emulation" of an Apple II that doesn't emulate
the hardware interfaces.

I see that you have the same concern.


Efficiency is a peculiar measure for a nostalgic labor of love...



Is it? labour of love or not, it's still an engineering exercise ;-)
The end result is what counts, ie. the nostalgic
recreation/restoration. If you think disturbing as little of the
original hardware as possible is a worthwhile goal, fair enough, but
I'm unconvinced that there's a lot more than can be done, improvement
wise, whilst doing that.


Yes, we are very much on the same page regarding engineering aesthetics.
My remark was a cheap shot.  ;-)

My big concern is that I continue to be able to sit down at a machine
that looks and feels like an Apple II, and open its case, and plug in
cards, etc.  If I had to give that up to get a 200MHz processor, I'd
consider it a bad trade.


It's worth a lot to me to keep the case, keyboard, and all the chips
when I take off the top.  ;-)



Cool. All I want to see when I lift off the lid is the 7 slots,
populated with whatever nostalgic device I so choose. I'm prepared to
trade the original board for that.


Good--that's great, as long as the game port, cassette port(s), and the
venerable speaker is also perserved.  ;-)


Careful--this way lies madness!  ;-)

Remember, I'm motivated by *constrained* resources, and feel that
"limitless" design environments are corrupting.  You don't have to
look far to see what I mean...



LOL! I'm with you on this one, believe me. I just like the idea of
surrounding that constrained environment with mod-cons, much like
adding a CFFA board does, except more.

People have invested countless hours of effort in adding modern
storage, modern networking et al. to the Apple II. Countless hours have
been spent on this forum extolling wacky new additions. All I propose
is an environment where these dreams can become reality, which to me is
a side benefit, as my primary goal is simply recreating my favorite
platform, plus my favorite third-party additions in a more reliable,
obtainable, and accessible way.


Yep--we're in "violent agreement".  ;-)


So what you really need is a virtualization of a 5.25" disk that lives
on a ProDOS hard drive.  RAM disk isn't much of a speed winner against
a hard drive, even with a Zip Chip.



Yes, I'd love to have this functionality. It could be achieved with a
peripheral card that replaced the Disk II controller, something I've
considered as a project. But really, building a bunch of different
add-ons using FPGA's seems like a ridiculous waste of effort, when you
could replace the motherboard instead, and have all the hardware you're
ever going to need for this, that or the other wacky add-on.


Actually, I was thinking more along the lines of a software emulation,
like DOSMASTER, though I realize that it would be no replacement for
the occasional Disk ][ grinding.  ;-)

You see, listening to protected games boot was fun, but I consider it
relatively inessential.  Deprotecting games was always a lot more fun
for me than playing them, anyway, and once they are deprotected, then
a software virtualization scheme like DOSMASTER works fine for most
purposes.  Then there's the real Disk ][ when it's needed...


The way things are going, no one will be able to *afford* to dispose of
a CRT monitor in another decade--anyone attempting to get rid of one
will be prosecuted as an environmental terrorist!



There is that aspect, for sure. An additional issue for me personally,
is that those displays are in much greater supply in the US than they
are here, we being a PAL country (btw, my IIe has a US motherboard
fitted, as the PAL compatibility of the Euro style boards is a hack at
best, and not having physical access to slot 3 bothers me)


Interesting.  I supposed that many of the high-quality monitors were
universal, but you are in a position to know.

As I've said before, I would like to be able to use a VGA monitor, as
long as it looks *just* like a hi-res NTSC-scan RGB monitor connected
to an Apple II.  This seemingly straightforward functionality is
apparently hard to come by, for a variety of reasons.  With your
approach, it could be done perfectly.


That approach illustrates the discipline required for a modular
design--good luck on recruiting Apple-oriented contributors, though.



Indeed. I think at a minimum though, anyone who's already contributing
to the Apple II arena with actual hardware has the discipline required.


I agree--and, unfortunately, that illustrates the point.  ;-(


I think that's debatable.  If you look at what people were fantasizing
about six or seven years ago, there is very little cumulative progress
toward a result.  And, I think, there is a potential downside if all the
fantasizing about the "perfect" detracts from individual contributors
going off and making "good" things that are real and very useful--like
CFFA cards.

Then, of course, there is the standard problem that if there are five
people discussing, there will be ten or more ideas of what "perfect" is.
;-)



All true. Although the device I'm promoting does create an environment
in which the barrier to producing these useful things drops
considerably, and provides the means by which we can tell the
fantasisers to just shut up and do it. win-win again ;-)


Nice!  ;-)


Although unless *I* actually shut up and do it, it seems unlikely we'll
ever get there :-)


ROTFL!

Go for it, Matt--you clearly understand the issues.  Now that I see
what you want to do, I'll be cheering for you all the way--and I'll buy
a couple when you've got it!

-michael

Music synthesis for 8-bit Apple II's!
Home page:  http://members.aol.com/MJMahon/

"The wastebasket is our most important design
tool--and it is seriously underused."