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


Michael J. Mahon wrote:

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

Yeah, when the softswitch gets hit. In practice, it doesn't matter
*that* much I spose, but copying a 3.5" disk using the expansion RAM
results in several of these glitches that I'd rather do without.

It's only since using the US motherboard that I've been able to use any
card other than a RamWorks III anyway; the RamWorks II and III are
identical electrically, but the III uses a more compact board layout so
it'll fit in the awkwardly placed Euro IIe slot location.

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.

Agreed. I'm using efficiency to refer to the complexity of the proposed
solutions; to me the simpler the design the easier it is to build, the
more likely it'll happen. Poor choice of language to illustrate my
point, but it's inefficient to my thinking to expend a large effort
(plus a lot of rather useful programmable gates) on only solving
individual problems, when it can be done once, for similar effort/cost
and be reusable.

But I see that we actually agree on this so I'll get off my high horse
now ;-)

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.

And pointless. software emulators already provide this as has been
mentioned many times.

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

Every single connector sans auxiliary slot, and slot zero. I'd provide
both keyboard encoders so the board can be fitted to either a Apple
II/II+ or IIe, although people using the original chassis might have to
desolder the 9-pin game port from the board.

Funnily, I consider it a bit 'wrong' to use the original chassis. My
II+ sits in a cupboard and never gets turned on. I pull it out
occasionally to show an interested party the funky made-in-ireland disk
]['s plus the marvel that is the one-man-effort motherboard inside. My
original generation gear is sort of a 'shrine' if you like ;-)

IIe's do practically everything the original machine does, have nicer
keyboards, weigh less, break less, do more. It's my favorite machine
ever made by any company, and I continue to use it frequently. I have
no problem at all popping it's motherbard + some of it's slightly more
exotic components out in favour of a replacement.

Of course, what I would do, is transfer my IIe to the 'shrine' with the
II+, grab one of the other platinum chassis I have lying around, and
replace it's empty accessible motherboard. They are still dime a dozen,
make sure you have spare cases ;-)

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

Yay!

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. ;-)

Hmm, you could always sample the sounds, chuck em on the FPGA, and have
it emulate the noises :-) That would be cute. I'd rather just pull out
a real one now and again - the sound of the disk ][ 'scraping' bits of
the disk is music to my ears, particularly when it's caught in some
wierd synchronised quarter track mode.

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...

I feel the same way about the protection schemes, and actually think
the ingenuity of them deserves preserving. The deprotected titles are
more convenient, when you're using physical disks, but a lot still
don't lend themselves to DOSMASTER style software since although they
restore the standard DOS sector format and are easily duplicated, they
often don't use DOS3.3 as an OS at all. Consider something like Prince
of Persia, which was to my mind, the absolutely pinnacle of 8-bit Apple
II entertainment titles. Did anyone ever get around to imaging the 3.5"
version of that? It would surely be very simple to hack, as it worked
just fine on the UniDisk 3.5" and must employ a very simplistic
protection scheme, if any at all.

Also, the vast majority of hacked versions out there are needlessly
"graffiti'd" and it's probably less effort to virtualise the disk ][
and use Copy II+ to rearchive them all from originals than it is to
rehack everything cleanly.

I find the hack screens a bit offensive nowadays, unworthy of my
'archival' grade ideas of preservation.

And yes, in the end it's a fairly superfluous 'enhancement' - but one I
picked as a potential use case for my vapourware motherboard :-)

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

To be honest I haven't looked at many as yet, you might be right. I'm
getting environmental enough these days that I'd rather not collect
them if I can avoid it. I've found 5-10 year old CTV's with SCART
connectors useful replacements for the interim assuming you use RGB,
but I'd rather ditch those as well!

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.

Yes. If you used a high enough scan rate, you could recreate the
grainy, blurry, NTSC signal quite well, plus the slightly more refined
RGB versions, and throw in amber/green mono for good measure. Make it
possible to have scanlines 'visible' or not. Skies the limit.

My favorite wish to be able to overide the DHR mode picked by software
that just assumed everyone was using a composite display, as it often
got it wrong.

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!

Thanks. I'm still a ways from commiting to the idea enough to see it
through. It's a big enough thing that I'd not bother with it if only I
was interested in the end result, and after all, the cost of
development is appreciable in a monetary sense, not just time and
effort. Having people within the community support the idea in concept,
plus expressing the desire to actually have one themselves is very much
appreciated.

Matt

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