Regular PDS Cards in Compact Macs

[PotatoFi]

I've been watching eBay for Asante ethernet cards just for fun, and I've noticed quite a few cheap "PDS cards" that I think are for other Macs. It makes me wonder if these can be adapted with a simple cable to be used in a compact Macintosh, like my Macintosh SE FDHD. There's quite a bit of available space in there, especially if the hard drive has been removed, and with the advent of 3d printing, it seems like making some brackets to hold different cards would be possible.

If they're electrically compatible, and it's just a formfactor thing, then it seems like a short ribbon cable could be used to connect them to the PDS slot on a compact Macintosh. Obviously, finding a suitable cable could be problematic, but there's gotta be *something* that would work.

If a suitable ribbon cable could be fashioned, and if mounts could be 3d printed... is there any reason why a standard PDS card wouldn't be used in a compact Macintosh?

 

[joethezombie]

It's an interesting proposition I've had on the back burner for quite a while.  Be careful of those Asante cards, they are predominately for the SE/30.  You can find pinouts for the SE PDS slot, SE/30 PDS slot, and LC PDS slot in the 3rd edition of Designing Cards and Drivers for the Macintosh Family (PDF available online).  They're all completely different pinouts, but the majority of the signals are the same, at least in name and description.   I've been meaning to grab a bunch of jumpers and connect the like-to-like signals from my SE to an LC ethernet card.  That would be the hardware portion.  Not sure how the software side of things would turn out.

 

[Bolle]

The SE does not work with the slot manager concept, so adapting a card that does might not be too easy.

I would start by looking if the address space for slot E is even free on the SE, otherwies you will need to swap around some address lines so the decoder logic on the network card still works.

We have talked about doing this with the SE/30 before. You will have to invert one of the address lines there to move LC PDS cards from slot space E to A. The card will still think it’s in slot E but the SE/30 will talk to slot A instead.

 

[Trash80toHP_Mini]

You will have to invert one of the address lines there to move LC PDS cards from slot space E to A. The card will still think it’s in slot E but the SE/30 will talk to slot A instead.

What will the driver think about that? Are you depending on an SE/30 driver to be available for the NIC? I think my PDS NICs are from Focus Enhancements, did they ever do a NuBus or SE/30 version/driver?

 

[Bolle]

The driver just talks to slot A and won’t think much I guess.

Still have this on the backburner and will try it someday.

 

[Trash80toHP_Mini]

I guess that might work if the driver is set up properly to work with the Slot Manager, but it doesn't need to be that way. The LC doesn't need to decode where the DeclROM is located because it can only be in Slot E. By inverting the addressing you'll have it popping its head up in Slot A, so the driver will need to be able to deal with that. Sticking to brands that made cards for LC and SE/30 may be a thing. By the time the LC Slot Macs shipped the SE/30 was an obsolescent, very expensive top tier Mac. Given the market penetration of the Low Cost Color Macs, Johnnie come lately NIC producers may have jumped in at that point and never having done or ever doing an 030 PDS or NuBus NIC. Heck, they never even needed to upgrade their LC NICs to the LCIII extended PDS.

Sorry, gotta ask 'em when they pop into the noggin. :/

 

[Bolle]

The host machine isn't decoding anything but the card has to listen to the address lines and wake up once it knows that the host is talking to it.

LC cards are hardwired to listen only to the address range of slot E.

The driver on the SE/30 won't even notice it is there though because slot interrupts and address lines are wired up to match slot A. Translation will be transparent to either side of the game.

Of course you will have to use some brand of card that has real SE/30 drivers. Drivers for LC only cards won't know what to do on the SE/30 (or the SE)

 

[Trash80toHP_Mini]

Yep, sticking to brands with SE/30 versions of the LC NIC in play was exactly THE THING I had mentioned. :approve:

 

[SE30_Neal]

Would it not be easier to copy the circuit of an se nic card and get them printed up in china? 

 

[Trash80toHP_Mini]

Components, firmware and drivers are needed, the PCB itself is a negligible cost. Someone it developing drivers for a new SE/30 board he designed with his hardware/PCB desiger partner. Somebody will post a link to the project.

 

[PotatoFi]

Someone it developing drivers for a new SE/30 board he designed with his hardware/PCB desiger partner.

It kinda sounds like that route has more merit than using a physical adapter for other PDS cards. I didn't realize there were so many differences, I had hoped it was physical only.

 

[Trash80toHP_Mini]

Practicality isn't an issue, joe and Bolle are backburnering it for the kick out of getting such a kluge to work and the learning experiences involved. Cool hacks have their own merit.

 

[SE30_Neal]

I knew someone would be doing something along those lines. Theres some clever and resourceful people on here, the clear case is a case in point! so I imagine someone will be knocking together a few accessories in a basement somewhere in the usa. If someone could now just develop an SE/30 accelerator card for around £100 that would to awesome as those things are not only rare as rocking horse poop but 4 times the price!

 

[maceffects]

If there is an adapter we can make, I’d be quite keen on looking into making them. I have 2,600 brand new LC PDS cards, and would love to make them more useful for other machines. 

 

[SE30_Neal]

There seem to be more LC PDS cards than LC’s on this planet!! How donyou end up with 2600 of them!!!! 

 

[Trash80toHP_Mini]

When this came up I mentioned to joe that he'd need something like the logic on this LC 68020 PDS card to SE 68000 bus adapter for that adaptation. This one adapts a VidCard made for connecting to 68020 SE accelerators to run directly off the SE PDS.

View attachment 25937

Bollie said one line goes to a signal that's tri-stated on the 020 bus. The Pal is connected to several Address lines I've mapped out and who know what else at this point? Unfortunately, that PAL isn't among the small set of PALs and GALs we can currently read when the security fuse is blown.

Going from 020 PDS to 030 PDS would be a lot easier. The keeping within one family of NICs thing for driver compatibility across platforms will be key. What brand are your LC NICs and did they make a NuBus, 68030 PDS and or an SE PDS version of that card?

 

[PotatoFi]

So I know I said "my Macintosh SE FDHD"... but if practicality limits this to the SE/30, so be it. I'm just glad to see discussion happening. Seems like getting something working on the SE/30 first is the way to go. Figuring out if there's a card that could work with the SE could always come later.

 

[maceffects]

Mine are Farallon EtherMac the driver disks that come with say they are for both NuBus and LC.  I purchased these in a lot, and if they can work for other Macs I’m sure I won’t be sitting on them too long. If memory serves they had SE and SE/30 cards too

 

[Trash80toHP_Mini]

It's all one big ball of twine tying the direct buses together from 68000<->68020<->68030<->68040<->PPC with the end trailing off into NuBus. Researching LC PDS NIC mfrs relationships between NICs they may or may not have made would be the first step in any of this I would think. If somebody does that kind of legwork that would be a big help to the sorcerer's guild.