How much of the 128K/512K hardware has been reverse engineered?

[Trash80toG4]

Wondering how far off "reloading" a board with reverse engineered hardware might be?

Thinking in terms of a new build 128K/512K hybrid board that can go either way at boot, depending upon which side of the repurposed programmer's switch is held down.

Has the Integrated Wozniak Machine been reversed?

So far out of my depth here it isn't even funny, but curious as all get out nonetheless.

 

[jajan547]

About to upload the Whole binder right now, five minutes and you all will be able to see.

 

[Trash80toG4]

Wow, that was quick, jj!

 

[Trash80toG4]

https://tinkerdifferent.com/resources/apple-service-technical-procedures-volume-six.78/

Nice, but not what I was asking. How much proprietary silicon remains to be reversed in order to do a New Build vs. Reloaded board with "knockoff components" in place of OEM silicon?

IOW, how close have we come/how far are we away from producing a 128K/512K Macintosh Clone?

 

[jajan547]

Sorry I meant to post this in my post on the mod I found, My apologies .

 

[jajan547]

Here's all I've been able to find schematics wise.

 

[trag]

Wondering how far off "reloading" a board with reverse engineered hardware might be?

I think the logic equations for the PLDs (PALs?) are out there. Maybe published in Mactech at some point.

I don't know about the IWM. I saw someone claim that Kai had reproduced the SWIM, but I haven't seen any such announcement -- which doesn't mean much given my chronic absence lately.

Also, it seems like the RTC (real time clock) would also be an issue. And does it also contain the PRAM static RAM?

Sound chips? Too early?

 

[jajan547]

Actually I’ve found a drop in replacement for the RTC I have in in a 512k board right now let me get the link for that chip.

 

[jajan547]

This is what I used, LINK. I've also attached the exact pinout of this chip below, which is an exact match to the original chip's pinout.

Here's a photo of the same chip in my 512k board:

 

[bakkus]

This is what I used, LINK. I've also attached the exact pinout of this chip below, which is an exact match to the original chip's pinout.

View attachment 7078
Here's a photo of the same chip in my 512k board:
View attachment 7079

That's a good find!
Could this also be compatible with other versions of the mac? Or just the 128k/512k?

 

[jajan547]

Well my original clock chip was very rusty, it worked but I didn't trust it so resorted to that and I've had no issues. As far as compatibility I don't know if that same chip was implemented on the Macintosh Plus I'd have to take both Machines apart to see.


Edit: The Macintosh Plus Real Time Clock is different from the 128k/512k.

 

[Trash80toG4]

I don't know about the IWM. I saw someone claim that Kai had reproduced the SWIM, but I haven't seen any such announcement -- which doesn't mean much given my chronic absence lately.

SWIM is a superset of IWM or 100% incompatible? If the former, might make for some great playtime.
Will the 128K boot from 512Ke ROM?

 

[jajan547]

128k will boot on a 512k, 512ke, and plus ROM.

 

[Patrick]

Will the 128K boot from 512Ke ROM?

yeah. the 512ke ROM is basically a plus rom.

if you install a romminator in a 128k you basically use plus roms when you do that.

you can also just drop in plus roms into a 128k and then you can use 800k drives.

 

[Trash80toG4]

Nice, thanks for the info on that.

@Kai Robinson what's the story on SWIM? How different is it from IWM and might it be dropped in as a replacement if nobody takes on the IWM challenge?

Does anyone have really high res pics of the 128K board to upload here? I'd like to set up the flow of the schematic on top of the board's layout of components so I can color code proprietary Apple silicon against stock ICs, what's reversed at present and what would be required for a doing the equivalent of Repro1. Coding what's available/not, reversed/not etc.

If nothing else it'll make for some interesting illustrations I think.

< wonders about CNC routed clear plexi layers . . . edge lit in a picture frame . . . >

 

[jajan547]

Hey if you can wait about 3 hours I’ll take some photos

 

[Trash80toG4]

Thanks, no rush at all, heading off to work in a couple of hours. If you could take a few at lower resolutions as well that'll be better for templates in Illustrator. High res would be for reference material here in thread.

Maybe post the pics in thumbnail mode with resolutions and component/solder side notation of CMP/SDR in the titles? That'll keep page load times under control?

 

[jajan547]

Sure thing I’ll see about it here in a bit, need the 512k too?

 

[Trash80toG4]

Sure thing, comparison will be fun.

Wondering how close we might get to 4MB Plus config starting out from original board design? 128K/512K upgrades are something I find fascinating. ISTR a memory upgrade developer releasing all over at the MLA at some point. It'll be interesting to see what a bootlegged clone for the DTP industry might have looked like.

Was it Argentina that cloned the Mac or was that the A2? Smuggling a bad**s clone into NYC would have been great fun in the day.

 

[Kai Robinson]

Nice, thanks for the info on that.

@Kai Robinson what's the story on SWIM? How different is it from IWM and might it be dropped in as a replacement if nobody takes on the IWM challenge?

Does anyone have really high res pics of the 128K board to upload here? I'd like to set up the flow of the schematic on top of the board's layout of components so I can color code proprietary Apple silicon against stock ICs, what's reversed at present and what would be required for a doing the equivalent of Repro1. Coding what's available/not, reversed/not etc.

If nothing else it'll make for some interesting illustrations I think.

< wonders about CNC routed clear plexi layers . . . edge lit in a picture frame . . . >

The SWIM chip is totally different from the IWM - however, the SWIM *contains* an IWM, and there's a crossbar switch that selects the relevant hardware inside the chip.

The IWM is essentially a consolidated Apple Disk II controller card this is well documented. Anyone that knows CPLD's, such as the Atmel ATF15xx series, should be able to shrink that into a 44-pin TQFP CPLD that can then be put on a carrier, slotted into the IWM socket. The SWIM, while well documented, might be harder to implement. Perhaps a Lattice iCE40 FPGA - with 26 I/O's in the BGA-36 package, they're available with 1248 LE's and fit into less than 1cm square.