MicroMac Performer Redux: Cloning a 68030 Accelerator for Compact Macs

[Trash80toHP_Mini]

This one is mine, it came as wonderful surprise in my Drexel 128K that had been upgraded to Plus and then to "4MB SE/30" status over the course its remarkably extended useful lifetime. Not one of the original, silk screened student versions we've come to appreciate, but a killer machine from the storied halls of Drexel University nonetheless. But that's another story

 

[Trash80toHP_Mini]

From the part number suffix, we'll assume my PGA 68030 powered Performer from 1994 is the 02 version representing an earlier generation of Performer.



Sometime in the 1994 timeframe, Micromac switched from the PGA Package to the SMT version of the 68030. The suffix appended to the same part number on the next example is 101A for what it's worth.

Can't say for sure, the designations may only represent which of the three connectors were installed for packaging/inventory purposes? If anyone has a Performer, posting pics or just the (c)date, part number, processor package and connector type would be much appreciated.

 

[Trash80toHP_Mini]

EvilCapitalist generously uploaded these images of the Performer he found as a nice surprise inside his Classic to the thread that started this all.

View attachment 21381

View attachment 21384

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[Trash80toHP_Mini]

The only apreciable differences between the CPU type versions I've spotted so far was a switch from discrete resistors to resistor packs on the SMT revision. Can anyone spot any other differences?

 

[Bolle]

Was going to post that one as well.

At least it made its way onto my desk now - will buzz out the connections once I can find some time.

 

[Trash80toHP_Mini]

Sweet! Are you buzzing that monster above or the simple little card I've made my project? Figured I'd put thruholes for my proposed PCIe 68030 PDS connector on my update of the Performer. Figured you might have something to plug into that someday. []

What do you think, will swapping a 50MHz crystal can for the 25MHz can on MicroMac's 16MHz accelerator card run the CPU at 33MHz?

 

[Trash80toHP_Mini]

I played around with connectors on perf board for a bit and decided my latest notion of using the 68030 PGA socket as a 68030 "PDS" expansion connector will work better than PCIe for adding a memory expansion shield or whatever.

Today was really good, my pair of 33MHz SMT 68030s arrived! [] Also sourced PLCC-20 thruhole sockets today, dougg3 said the SMT sockets he used were a bear to install. These should be a lot easier unless trace congestion should force use of SMT sockets after all. I may order both.

Do SMT PLCC sockets install easily using a hot air station?

 

[Trash80toHP_Mini]

Realized my verbal explanation of the 68030 PGA Socket interconnect wasn't at all clear and that one of my AI diagrams won't suffice, so:



This board handily illustrates what I'll be attempting to fit on my first 10cm x 10cm SEEED board. By dropping support for the Classic, the hole in the middle of the board for the A/B cable goes away.

The thruholes you see for its 68 pin socket interface (it's really more, but we'll say 68 for simplicity's sake) will become a three ring PGA array for a socketed 68030. That allows for testing both processor packages on my board.

A fifth GAL socket will be added to match the loadout of the Performer.

Visualize the SE's 68 pin EuroCard PDS connector (same as used for a NuBus card) added to the above card per the Performer config.

Space limitations will likely require dropping the 68000 socket to keep the prototype within the confines of an inexpensive board, but can be added to the final version as could the crazy form factor for Classic compatibility.

As a last resort, the FPU socket will be dropped from the prototype form factor to reclaim its PCB acreage. A purist I'm not.  [}]

 

[Trash80toHP_Mini]

edit: while in merciless KISS editing mode, I decided to replace the standard SE connector on the prototype with the right angled version. Testing with the card mounted vertically in the SE like an SE/30 expansion card in a Late SE or SE/30 chassis simplifies things remarkably well.

 

[Bolle]

You should leave space for a PDS passthrough :evil:

The PDS in the SE was not spec'd for more than one card but that must be because there are no slot IDs and IRQs for multiple slots.

In the SE/30 at least an accelerator does not use up a seperate slot ID, so possibly we can get away with let's say an accelerator and a network card maybe?

Anyone ever tried that?

 

[Trash80toHP_Mini]

That would definitely work as that's exactly what Radius did with VidCard connectors on their accelerators. Their Magic Bus Card is a passive PDS adapter for use when no Accelerator is available.

A much longer card would be necessary and we'd need to find the oddball connectors or harvest them from Magic Bus Cards. I've got one that's in the For Parts Only category.

The only NIC I've ever had was traded away, but was in the full size SE form factor which wouldn't fit up the SE/30 stovepipe. Any SE compliant PDS card of any sort could be converted for the use with a vertically mounted PerformerRedux in the late SE/SE/30 chassis. Replacing the standard  male "NuBus" type soldertail connector with a female wire wrap connector would do the trick. Soldertails would plug into the PDS and the accelerator would plug vertically into the hacked in EuroDin-96 Female wire wrap socket. Again, SE/30 type chassis required.

Haven't even looked at clearances for doing it any other way, baby steps for a change. :mellow:

 

[Trash80toHP_Mini]

 

[Trash80toHP_Mini]

 

[techknight]

The problem with cloning these guys is the hidden magic in the PAL/GALs, How do you get that? 

 

[Trash80toHP_Mini]

Pretty much the same way we (and I use that term very loosely) got ProtoCache1 up and running. joethezombie did the magical job of brute forcing the basic functions of his IIsi Adapter GAL. Then he and our resident wizard Bolle worked out equations to get that IIsi adaptation up and running. Bolle divined the function of the DiiMO adapter GAL, developed the equations (along with Joe?) and now that's up and running on Bolle's SE/30 DiiMO clone boards.

joe's on hiatus for a bit, real life tends to soak up development time. Hoping he'll play with my Performer's GALs upon his return. Bolle has a lot of applicable, open source information from the Amiga side of things and elsewhere for GAL equations needed to interface a 68030 accelerator with a 68000.

Me, I'm just playing at electron plumbing again, figured this was as good a time as any to get into the email order PCB game.

Did a rough pasteup at work just for you and Bolle. It would have to have a really screwed up PDS pinout though.

  View attachment 21423

Gals look smaller because they're surface mounted rather than socketed, needed the real estate. That's not a PDS passthru, but maybe it's enough pins to support something the likes of the Daughtercard on Bolle's Quesse/Gemini accelerator.

 

[Trash80toHP_Mini]

I'm going to start pulling together information scattered hither, thither and yon.

Bolle: PowerBook 100 Accelerator Insanity thread:

Those equations usually are pretty basic. There existed a DIY project from german c't magazine that was about building a 030 accelerator for 68000 machines. They had GAL sets for the Amiga as well as the Mac. All the documentation on those is found on the web somewhere. Pretty sure if you compare the GAL connections on their board and on most of the commercial accelerators you will see that they all have a lot in common.

Your Micromac should always work in 030 mode even without the INIT - at least all my 030 accelerators for the SE and Classic do. Disabling the 68000 is done the same way as the onboard 030 is disabled on 030 PDS/Cache upgrades. Pretty sure you won't need a 68000 at all for the upgrades to work.

The logic can be done in a modern PLD. Just look up the TerribleFire. That thing actually should not be too hard to be modified to work in a Mac - minus the onboard DRAM which is software activated on the Amiga I think. SRAM could be implemented with some cache logic instead to speed things up. How cache is hooked up to the 030 bus is also well documented on the net somewhere, including needed GAL code and everything... I have it backed up somewhere in my 030 accelerator folder that is hiding somewhere.

Bunsen came up with some great info in a post that seems difficult to quote.

Link to a description of the C't accelerator he provided. THX, B!

 

[Bolle]

That would definitely work as that's exactly what Radius did with VidCard connectors on their accelerators.

Should I take your word on that? :evil:

Prepared something but are a little bit scared to actually plug it in

 

[Trash80toHP_Mini]

edit: UNPLUG THAT MEMORY BOARD FIRST!!!!!!!

hOW THE HECK DID YOU GET THAT CENTER ROW SOLDERED? pASTE/hOT aIR?????

edit3: (*&#$ cAPSlOCK! Tricky tricky: double row then single row!

I can buzz the connections on the Magic Bus Card if you'd like. [}]

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Flights of fancy and a 10cm x 10cm PCB to design after I tear my Performer down to the bone. []



How many pins are on your Memory Card interface?

edit: forgot to switch back to sockets for the GALs in this layout. Also might drop the FPU for a 68030 PGA Socket for the prototyping stage. SMT GAL sockets free up a lot of acreage on the solder side and should fit on the component side with little problem. Dunno, images are still spinning around in the noggin. Condensing the prototype down to 10cm x 10cm Accelerator/VMem inclusive board for the SE PDS sans FPU is probably the sane thing to do. Implementing the FPU subset of the PGA CPU socket down to an FPU socket after the SMT CPU config is finalized will be child's play.

 

[Trash80toHP_Mini]

KISS - Bad to the bone! Orange is on you, buddy!