Dual Serial Cart Mk I

[CommodoreZ]

Howdy folks. Not long ago, I got struck with the notion to build a faster serial interface for the VIC. Next thing I know, I've got a working card with two serial ports.

You can find more information here:
https://www.commodorez.com/vicserial.html

Or watch a demonstration of it in action here:
https://www.youtube.com/watch?v=bPr6GPhOzXw

[Mike]

Nice!

The photograph is somewhat small ... do you use a 6551 ACIA or some other serial chip for this? (Edit: on your website I see these are two 6850, actually) Those two ceramic ICs are for sure quite expensive.

One small suggestion: you should rename both JP1 and its options ("IO Block Select", "BLK 2" and "BLK 3"), maybe into "I/Ox Select", "I/O2" and "I/O3". Otherwise people might confuse this jumper with the BLK2 and BLK3 select lines on the cartridge port which refer to the address ranges $4000..$5FFF and $6000..$7FFF, respectively.

Greetings,

Michael

[CommodoreZ]

The photograph is somewhat small.

Here, these are much bigger:


I borrowed the old ceramic parts for these out of other projects since they look so beautiful. Pretty chips should be useful as well as ornamental.


I've not had great luck with 6551's (both older NOS varieties and new WDC models), so I opted for a chip I knew, and could get NOS without much trouble, hence the 6850s.

One small suggestion: you should rename both JP1 and its options ("IO Block Select", "BLK 2" and "BLK 3"), maybe into "I/Ox Select", "I/O2" and "I/O3". Otherwise people might confuse this jumper with the BLK2 and BLK3 select lines on the cartridge port which refer to the address ranges $4000..$5FFF and $6000..$7FFF, respectively.

I will take that into consideration.

I ended up building 2 of them, plus an original prototype which I won't post here because it's virtually indistinguishable and had a few signals swizzled.

Here's from when I was testing that two of them wouldn't conflict when plugged in together.

[mingle]

It would be nice to have one of the ports as a DB-25 to make it a bit simpler to connect stuff without the need for an adaptor?