Expansion cards

[benchoff]

What's the possibility of putting an expansion card header on the board to break out the address, data, and interrupt lines?

With luck, this thing might take off, and it would be a shame if it can't be upgraded with additional hardware (maybe a homebrew SCSI card?)

[simon]

I think this is a good idea. I once had bus connectors in the design but dropped them when I was thinking about adding drivers or saving board space.
Maybe I just add some (one or two) edge-connectors (like for ISA cards) without drivers as compromise. Then it is up to the user to add drivers for an add-on card if needed.

Simon

[benchoff]

If I could make one small suggestion, use a DIN 41612 connector. Looks like this:

http://www.mouser.com/ProductDetail/TE-Connectivity-AMP/535032-4/?qs=sGAEpiMZZMvkWeVFEbAjO8SozB4AR3wtBEWhHTCVqOY%3d

Yeah, we finally have a use for all those old Nubus cards...

[Brian]

I personally don't see a problem with expecting the user or designer to supply their own driver for an expansion card, although building in support for cards that everyone uses (for example, a Blinkenlights front panel module) might be nice. However, the base system has so much already built in that anyone expanding the system can fully document their expansion and provide a sample "driver" or ROM modifications and take the heat away from the core development team. I do feel that expansion capability becomes necessary, though, because someone will eventually find a use for the machine in which they need 8 serial ports or the ability to interface to an old IEEE488 system.

[simon]

If I could make one small suggestion, use a DIN 41612 connector. Looks like this:

http://www.mouser.com/ProductDetail/TE- ... HTCVqOY%3d

Yeah, we finally have a use for all those old Nubus cards...

Nubus... I don't have any of these cards. And even ISA cards are getting hard to find. Shouldn't we go with an simple proprietary connector? That way we don't need to fiddle around with achieving compatibility.

I personally don't see a problem with expecting the user or designer to supply their own driver for an expansion card, although building in support for cards that everyone uses (for example, a Blinkenlights front panel module) might be nice. However, the base system has so much already built in that anyone expanding the system can fully document their expansion and provide a sample "driver" or ROM modifications and take the heat away from the core development team. I do feel that expansion capability becomes necessary, though, because someone will eventually find a use for the machine in which they need 8 serial ports or the ability to interface to an old IEEE488 system.

Uhm well, I hope ther will be a core developer team.

As for the blinken lights one could use some free port lines for driving LEDs. For example a programmable power LED like done in the Amiga.

Simon