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-   -   Zorro slot on A600? (http://eab.abime.net/showthread.php?t=98212)

lord of time 25 July 2019 05:46

Zorro slot on A600?
 
I was wondering if a zorro slot could be added to a 600 via the memory expansion bay port? it could be usefull if posible

Jope 25 July 2019 06:58

No, you would have to get the signals from various points on the motherboard. Many are available on the CPU.

Locutus 25 July 2019 10:01

exactly where would you leave the card itself? most Zorro cards are larger then a A600.....

AmigaHope 01 August 2019 08:37

I will eternally curse Commodore for not including a Zorro 1 connector (A1000/A500 sidecar slot) on the A600. =( They provided no way to get at the signals other than the damn CPU socket.

I think the CPU socket has all the pins you need though -- so could use the PLCC-socket-on-top-of-68000 trick and maybe need to solder one or two more bodge wires on, then you could run a ribbon cable out the side to a Z2 backplane. Can get away with ribbon cable since Z2 is pretty tolerant of line lengths.

The question is -- why? A500s are plentiful and much easier to convert to support Z2, and you lose to compactness benefit of the A600 once you hook it up to a Z2 enclosure (or hack it into a tower).

Daedalus 01 August 2019 09:57

The A600 didn't really need it. It was fitted with expansion capabilities that suited its role as a small, integrated computer. The main use of the sidecar slot on the A500 was for hard drives, and the A600 added that capability internally for much cheaper and neater expansion. Most other things could be added with PCMCIA - fast RAM and SCSI being the two main uses.

It wasn't intended to be heavily expanded, hence no facility for CPU upgrading. It was entry-level, to fit the market for unexpanded A500s, with the A1200 being the more expandable one with a dedicated CPU expansion slot. Yes, it could be added by tapping the required signals from various places on the board (not possible from the trapdoor connector), but it would likely need to be buffered to run it to a serious length. Zorro-II is tolerant of lengths, but it's always buffered in the A2000 (as is Zorro-III in the 3000 and 4000).

Indeed, I do have to wonder why?

themamboman 01 August 2019 15:32

Someone was working on a custom one, see his posts and pictures here:

http://www.amibay.com/showthread.php...l=1#post484768
http://www.amibay.com/showthread.php...l=1#post496387
http://www.amibay.com/showthread.php...l=1#post496597
http://www.amibay.com/showthread.php...l=1#post722269
http://www.amibay.com/showthread.php...l=1#post880129

Daedalus 01 August 2019 16:42

Cripes, that's an impressive project!

AmigaHope 02 August 2019 22:07

Quote:

Originally Posted by Daedalus (Post 1335706)
The A600 didn't really need it. It was fitted with expansion capabilities that suited its role as a small, integrated computer. The main use of the sidecar slot on the A500 was for hard drives, and the A600 added that capability internally for much cheaper and neater expansion. Most other things could be added with PCMCIA - fast RAM and SCSI being the two main uses.

It wasn't intended to be heavily expanded, hence no facility for CPU upgrading. It was entry-level, to fit the market for unexpanded A500s, with the A1200 being the more expandable one with a dedicated CPU expansion slot. Yes, it could be added by tapping the required signals from various places on the board (not possible from the trapdoor connector), but it would likely need to be buffered to run it to a serious length. Zorro-II is tolerant of lengths, but it's always buffered in the A2000 (as is Zorro-III in the 3000 and 4000).

Indeed, I do have to wonder why?

I'd argue that the A600 would have been way better off including a SIMM slot for the extra 1M chip RAM expansion, and had the trapdoor slot carry the CPU bus instead of the ECS bus. That would open the door to proper expansions. They had years and years of real world demonstrations of how creatively people could expand the A1000 and A500 given proper access to the needed lines.

Including Zorro 1 edge connector would have been a less elegant way to do this, but would have the advantage of allowing compatibility with the literal hundreds of expansions that already existed for the A500/A1000.

Moreover they could see that the A500's trapdoor slot was used for almost nothing except RAM expansions (though there were a few clever hacks like an IBM PC-compatible card).

Why create what's essentially a proprietary RAM expansion port when SIMM slots already existed as a cheaper way to use commodity hardware? It wouldn't really increase sales of expansions for Commodore since third parties could (and did) easily make cheaper A601 clones.

Matt_H 02 August 2019 22:55

Quote:

Originally Posted by AmigaHope (Post 1336089)
Why create what's essentially a proprietary RAM expansion port when SIMM slots already existed as a cheaper way to use commodity hardware?


Simple: SIMM slots cost extra money; exposed contacts on the PCB don't. Plus they'd still need a way to allow users to add an RTC to the system.


Remember, C= engineering intended the A300 A600 to be positioned below the A500 in the marketplace. It was supposed to be *really* cheap.

Mick 04 August 2019 20:48

Reverse engineer the A600 board and try to squeeze in a DIP socket rather than PLCC? that would seem like the easiest way to open an A600 up to existing expansions assuming you can fit the socket in a location that won't be physically blocked.

Or maybe you can already get something like the A500 re-locator that clips on the PLCC CPU?


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