3 Slot Expansion Card Comments Requested

[brain]

Trying to fill a small gap, I'm working on a 3 slot expansion port solution ala EX-3 or FB-EX3.  Here is a first cut of the PCB design:

http://www.jbrain.com/vicug/gallery/xpansion/ext3_d

Comments are appreciated.  Some things I'm curious about:

• Is the switch location OK, or do people need them off to the side?
  
• Does anyone want a top slot for the 3rd slot?  or is the back entry desired?
  
• Any other features besides the existing ones that are desired?
  

Jim

[commodorejohn]

A back-facing slot is nice for large or unusually-shaped cartridges like the Commodore REUs or the Sound Expander, at least in my opinion.

[Mark Smith]

I posted a reply over at retrohackers ... but let me post here as well ....


Cool!

I'd say move the jumpers and DIP switches off to one side, most people are lazy (ok well maybe just me ..) and would not remove the carts from the board while trying to fiddle with the jumpers and DIP switches this runs the risk of over stressing a cart in it's slot.

Also put in the BIGGEST switches you can, nothing worse than fiddling with DIP switches with the end of a pen (ala back of 1541-II drives) .. plus all us "enthusiasts" are getting older

Being able to swap the IO1/2 lines is a good feature of the Fotios board.

The ability to easily (and completely) disconnect a board from the bus without removing it would be handy so that if you have 2 board that don't play nice together you can turn off one slot ... one big button per slot ?

And how about an option ROM socket ? Maybe taking up a pseudo "slot 4" with a bank select for the larger EPROMS ?

One other thing ... I've read that the C128 has a "noisy" bus ... is this noise something that could be cleaned up or filtered by some cleverness on the expansion port ?

Anyway .. whatever you make will be nice

Regards

Mark

[redrumloa]

Great to see you making this! I would *much* prefer the 3rd slot to be back entry. Switch locations don't bother me as long as the switches are through hole and not surface mount, as I'd be relocating them in my tower.

For extra features, only thing I could think of is maybe a clock port to plug in things like a Silver Surfer or MP3@64? That may be asking too much :-)

[RobertB]

I'd say move the jumpers and DIP switches off to one side...
Also put in the BIGGEST switches you can...

Being able to swap the IO1/2 lines is a good feature of the Fotios board.

I agree with the above points.

The ability to easily (and completely) disconnect a board from the bus without removing it would be handy so that if you have 2 board that don't play nice together you can turn off one slot ... one big button per slot ?

And how about an option ROM socket ? Maybe taking up a pseudo "slot 4" with a bank select for the larger EPROMS ?

These too would be nice but are not mandatory.

Truly,
Robert Bernardo
Fresno Commodore User Group
http://videocam.net.au/fcug

[Hydrophilic]

I think the rear/3rd slot design is fine for reasons mentioned above.  Also as said, switches should be moved to the edge for easy accessibility.

I think a pin header would be nice for hardware hackers... plus it should be realitively cheap and easy.