How hard is it to design and build a Zorro II or III card?

[marcfrick2112]

Hello all, knowing I know only a little about electronics, in layman's terms, what is required to build a working Zorro II/III Card? A simple project to start?

[jasonsbeer]

A very open ended question...here are some ramblings...Z2 is simpler than Z3. If you know little about Amiga and Motorola architectures, Z2 is where you start. They are both parallel buses (not serial). Z3 is multiplexed and I understand the timing is very sensitive. Good references are the Amiga Hardware Guide and the A500/A2000 technical reference manual. Both should be easy to find with a search of the internets.

Where to start...

1) Understand the 680x0 bus
2) Understand AUTOCONFIG
3) Learn to program CPLDs and/or FPGAs to handle the interface between your hardware and the Amiga

The simplest project I can imagine is simply getting AUTOCONFIG to work. Your card doesn't actually have to offer any real features to be recognized. Set it up as an I/O device with a made up manufacturer number (or borrow one for exploration). If it shows up in the devices list, you were successful.

The next simplest project would be anything that does not require ROMs or drivers. A memory card would fit that description.

[grelbfarlk]

It's easy, super easy. If commodork wasn't so inept they would have made lots of Zorro cards. What do you want in a Zorro card? RAM? An HDD controller? A Neutrino radio with SANA-II drivers?

[marcfrick2112]

Thanks, I was just curious.

[qz3fwd]

Originally Posted by grelbfarlk

It's easy, super easy. If commodork wasn't so inept they would have made lots of Zorro cards. What do you want in a Zorro card? RAM? An HDD controller? A Neutrino radio with SANA-II drivers?

Perhaps they just didn’t have the money and/or resources? Trying to give them the benefit of the doubt here. OTOH Commodore barely evolved the architecture from 85 to their demise so……..

Additionally since they rolled their own architecture and had a minuscule market penetration they did not really benefit from the huge pool of manufacturers producing add in cards to the PC ecosystem, though you did see some PC technology grafted to the Zorro standard.

[Daedalus]

For its time, Zorro was a pretty decent standard, and Zorro-III is a massive step up from Zorro-II, so it's not like they didn't make any upgrades during that time. To use PC commodity cards at the time meant using an ISA bus, which is a lot more work to graft onto the 68000 bus, a lot more primitive and a lot less user friendly. Autoconfig was streets ahead of manually configuring ISA cards, which was a massive pain in the hoop that was only overcome with the introduction of PCI (which itself is quite similar in many ways to Zorro-III).

The Zorro standards were, and still are, well documented for anyone who wanted to develop their own cards. Some good information can be found in the Hardware Reference Manual. As was said, the first step as a project would be to get Autoconfig working, which can be achieved with a fairly basic CPLD.

[NevadaTech]

Does anyone know of a generic/open source Zorro II card for bread boarding/testing/building? Ideally a full sized card with the basic edge connectors. Hopefully, the edge connectors trace up to the main area of the card where 'through holes' are available for power/signals/bus tapping.



Mind you, I do not consider this a hijack since it contributes directly to the OP.

[grelbfarlk]

I'm trying to remember what it was called. There's a link to the thing I think I was thinking of, but it redirects to amiga.org.ru, so I think some link hijacking took place:
https://eab.abime.net/showthread.php?t=69913