ReA4091: SCSI2 on Zorro III for everyone!
 

Hi and welcome to the latest and greatest project by Chris Hooper and me: ReA4091.

All in all there were only two ZorroIII capable SCSI controllers ever made: The A4091/DKB4091 and the Phase5 Fastlane Z3. The Fastlane, by being a closed source fortress, is completely useless. It can not be repaired, or improved. But all GAL logic source code for the A4091 has been made available by Dave Haynie.

So on my first visit to Germany since the pandemic started, I was finally able to pick up a DKB4091 that I "won" on eBay. Back home in sunny California, a new project was born:

https://eab.abime.net/attachment.php...1&d=1637546337
https://eab.abime.net/attachment.php...1&d=1637546337

November 2021:
At the moment the project is in its Proto0 phase. Schematics and PCBs have been drawn and verified, and we had OK2FAB last week. Now waiting eagerly for the PCB delivery so that we can jump right into our board bringup late November / early December.

Of course there are countless ideas already:

• Move the GALs and other logic chips into a CPLD
• Use the additional space to add some RAM
• Since the NCR53C720/725 can also cope with the 68030 bus, they could be a potential upgrade path
• The card could be shortened to save cost
• Integrate SCSI2SD

Ideas, ideas, ideas, a dime a dozen. But for now the goal is to produce a working board that is as close as possible to the original (plus easter eggs of course)


January 2022:
The board is fully working.

February 2022:
Time to order the first small batch with a few minor cosmetic changes. Lunar New Year put a serious delay on us, as expected.

March 2022:
Building boards, making boxes, manuals, and got amazing brackets from Szymon Gosk

April 2022:
Interested in getting a board? Let us know about Pre-Order Interest so we can plan. There will also be a release of schematics / gerbers / BOM, but don't hesitate to fill out the form if that's what is interesting for you.


--
amiga.technology blog
Amiga Hardware Pics (Instagram)
Stefan's GitHub (Romy, 68060 adapter, etc)
Stefan's Twitter <-- follow for updates

This looks like an interesting project, I might get one to replace my Phase 5 Fastlane Z3 card.

Small update

http://eab.abime.net/attachment.php?...0&d=1638473293

I'm always amazed at what dedicated and knowledgeable Amiga fans can achieve! :great

For the future extra features it would be nice if the re-created controller could easily utilize the RaSCSCI solution.

Nice project. Do you intend to open source it?

I have wanted an A4091 for a very long time, great stuff!

Do you intend on selling pre-assembled cards, or PCBs? If the latter, I am up for one PCB :D

Still figuring the details of distribution out. First the card needs to be working. The hope is to open the design up, of course. Life is too short to waste it on closed source stuff.

Following!

Great to see this project! I don’t have a particular need for a 4091 right now, but I might in the future. If so, I’d be interested in a fully assembled card - I’m not skilled enough to assemble from parts.

I could assemble some card for others.

Shaf

Awesome work!

Nice. That is a huge zorro card!

Really great project, i am excited which way it will continue :cool

Unfortunately is RaSCSI way to slow for this card.

I need this in my life <3

True, but as one device of many it could be useful to include PI mounting holes in the area on the PCB where the HDD goes.

That's right, mounting holes for:Raspberry 2-4, Zero and SCS2SD 5 + 6 would be nice.

Really nice!!

Looking good:

http://eab.abime.net/attachment.php?...0&d=1638728521

http://eab.abime.net/attachment.php?...1&d=1638750366

Wow, outstanding work!

:bowdown :great

That looks like a lot of logic - can't those be consolidated?
Cool stuff!