GSed Props?

davidsaunders

As I near the completion of the MuAmi, I am looking beyond that to something that I can really enjoy.
My next thought, is to clone the Apple IIgs. In my life there have been 5 computers that I have truly enjoyed, the Apple IIgs, the Commodore 64C, the Atari ST, the Atari TT, and the Amiga. Of these the most enjoyable all a round IS the Apple IIgs, becouse it is the most hackable, the least limited, and the best documented. It does help that WDC is still around so I can still buy 65C816 CPUs.

I ask every one who may be interested in this topic:
What has already been done towards the IIgs HW emulation/replacement with the Propeller? AND What do you think would be the areas best suited to the Propeller as far as IIgs components, and peripherals?

I am looking forward to doing the best Apple IIgs clone yet seen as soon as I finish the MuAmi. The MuAmi has shown me the face of amiga users that I did not know about (and is fairly ugly), unfortunately most of them are proclaiming that they do not want to see another 68K Amiga.

potatohead

Well, I was always partial to the 6502 Apples myself. The GS is a nice machine though.

I've a //e platinum waiting on a good power supply. Frankly, I think it would be interesting to:

1. Use our 6502 core to emulate the ][ series.

2. Stuff a prop on a card for the ][ / GS, which is why I got the Apple in the first place, along with having a emulation reference.

davidsaunders

For your idea of emulating an earlier generation Apple II, I like it. I have always been partial to the GS as IIs go though. could I recommend getting a WDC65C02S and building around that, so that you can have more Prop left to do the heavy lifting?

potatohead

Well, there is this:

http://www.parallax.com/tabid/708/Default.aspx

I stocked up to build it, and just never did. On that one, the Prop is wrapped around the 6502, clocking it, etc... You might find that work very relevant.

For me, the idea of building to some other CPU to clone a retro-computer just doesn't appeal much. Guess that's why I never built the 6502 board. It's much more interesting to have it all on the Prop, even if it takes a coupla props. Programming the Prop is a lot of fun! I can program 6502, 6809 (which is still pretty damn fun), and a few others, but... I don't want to do anything other than glue / interface type stuff on those, because the Prop is where the relevancy and fun is.

That's just me though! Don't let me get in the way. I really was just riffing a little because you said, "Apple", LOL!!

A area of current interest is interfacing. The way I see it, the Apple ][ has a nice 1Mhz bus that's tolerant, and that is extremely well documented, and with the right kinds of signals to learn on. Of all the older 8 bitters, I think it's probably the most open, and I really did a lot on the things back in the day, so the machine itself isn't a significant obstacle.

Apple ][ machines were actually fairly serious computers, limited as they were. First step is to get the Apple running, and some basic software, meaning some DOS and utility disks to load programs via serial, and to use the disk for a coupla minor boot strapping things. Then, build out a prototyping area to do said interfacing. Where it goes from there, who knows? I get to put my collection to use. Scope, temp controlled solder station, etc... Maybe I'll end up with a nice little dev station. I think I'll want to build up a Prop logic analyzer too. The base clock in those things is 14Mhz, and that seems within reach of a Prop.

davidsaunders

I never much used the early generation A2s, though I do not see where the limit is in up to 8MB RAM, expandable video, up to 8GB SCSI, etc, all in a system from 1991 (the IIGS).

potatohead

The limit was on the 6502 / 65C02 machines. The GS was considerably more powerful with it's 8/16 CPU. Never used a GS. At that time, I was still using a ][ for a lot of stuff, and I had a nice one! Was stuffed with a nice batch of cards, and I sold it for a few hundred bucks. Kind of wish I hadn't, but the //e platinum I just scored has the basics. Super serial, disk card, built in 80 columns, and some reasonable on board graphics, if needed for data display. It can still be stripped down to just the monitor and basic, if I want to. So that and a CoCo 3, were my programming / learning computers, and a fairly crappy PC clone was the work machine, doing some CAD and telecommunications. I actually did a fair amount of writing on the //e, and probably will knock out some stuff on this one, just because I really like the machine for that particular task.

So I missed the entire "cool" 16 bit era, making money on IBM PC clones, and "playing" on 8 bitters. It wasn't but a year or two, and I had ditched all the 8 bit machines, keeping the PC, and was into IRIX for serious, higher-end computing. I go through cycles, it seems, because I gave away a very solid IRIX collection, much like I did the 8 bitters. For now though, the stuff is cheap, so it can all come full-circle for not a lot of money. Mostly scrounging

Anyway, rock on. Will be interesting to see where you get to on the GS project.

Cluso99

I am interested, but currently a lack of time for all my prop projects. I am with potatohead in that I want to use the prop for the emulation as well. But that does not stop us from making the rest of the machine with the prop and then we could substitute a prop for your 65816 processor. I threw out my Apple //e's and Apple //c (Apple gave me the //c preproduction unit with a plaque - I could cry) and most of the disks. However, I discovered I did keep a couple of books and a few ProDos disks. I have an unused prototype card. I built comms pcbs to connect the Apple to IBM mainframes that go inside the Apple //e & the replacement which was canned and later evolved into the gs. It was a fun time back then.

potatohead

I would be very interested in that prototype card, and disks, which would save me fetching them over serial to make masters. Is a deal possible??

Cluso99

Wondering how I can read or copy the disks. Was it possible to copy on a PC with 1.2MB floppy drives??

potatohead

I don't think so. The disk write format was unique to the Apple, and done in software, soft sectored. I can always setup to fetch images from the net with ADT, over the serial port. Will have to try that with the Prop as well.

ctwardell

Here is an Apple 1 (yes 1), that uses a Prop to do the video.

http://www.brielcomputers.com/wordpress/?cat=4

Quote from the page: "Improved video display using Parallax Propeller (works with most TV’s and monitors)"

C.W.

davidsaunders

Cluso99:
You can use ADTPro, borrow an Apple //E or better Apple II, hook it to the PC through null modem cables, and copy your heart away. Sorry I can not help as my Apple IIGS only has a 3.5 inch 800K floppy drive, a CDR drive, and a 40GB HDD for drives.

davidsaunders

Cluso99:
Do you really think that a Propeller could emulate a 65816 at 12MHz? I would like to figure out how to get this kind of speed out of a emulated CPU on the Propeller, I have been playing around with trying to get a subset of the 68000 up to speed (so far I have got a 68000 subset running equivalent to a 2MHz real 68000, only accessing hub mem).

Cluso99

david: No I don't think a Prop could emulate a 65816 @ 12MHz. However, IIRC 6502 does a divide by 4 from the xtal and then there are multiple cycles from there. So, it may go close.

I do not have an Apple any more so unless I can read on a pc - I kept an old 1.2MB 5 1/4" floppy drive - I would have to find someone to copy the disks.

davidsaunders

Cluso99 wrote:

I do not have an Apple any more :frown: so unless I can read on a pc - I kept an old 1.2MB 5 1/4" floppy drive - I would have to find someone to copy the disks.

Cluso99:
If you know some who has an Apple II in your area, you may be able to ask them to lend it to you. If I had a 5 1/4" floppy drive for my Apple IIgs I would be glad to do so (unfortunately I do not [never needed one]). The PC can NOT read the Apple Prodos and DOS 3.3 disks. The sectoring is quite non standard, and the controller will not allow you to read the sectoring correctly. This has nothing to do with the drives themselves, it is an issue of the Controllers used in PCs. On the other hand if you have a 68k, or PPC Macintosh or Amiga with a 5 1/4" floppy drive you can read them no problem.

Cluso99

Thanks David. I thought I recalled years ago someone did a program that read apple disks on the pc - I must be confused with something else.