Re: VIC-20 "smart" expansion port idea

From: Ethan Dicks <>
Date: Mon, 11 Jan 2016 15:16:07 -0500
Message-ID: <>
On Mon, Jan 11, 2016 at 2:56 PM, Marko Mäkelä <> wrote:
> So far, nobody seemed to answer my question about Vic-20 cartridges that use
> I/O2 or I/O3.

I built a one-off on a protoboard - a Motorola 6821 to give me 2 more
8-bit ports, wired into a DEC single-slot backplane socket to make a
board tester.

Do any of the VIC-20 IEEE cartridges use I/O2 or I/O3?

> I know only one such cartridge: the tape fastloader Vic Rabbit
> maps 4KiB of ROM there.

I had the PET Rabbit (just a 2532 in an empty ROM socket), but not the
VIC Rabbit.  Interesting to hear it had a non-standard ROM select.


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Received on 2016-01-11 21:00:51

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