Re: 1 MB image for VIC-20

From: MagerValp (
Date: 2001-02-15 17:02:45

>>>>> "MM" == =?ISO-8859-1?Q?Marko M=E4kel=E4?= <ISO-8859-1> writes:

MV> I haven't counted the number of Vic-20 ROMs out there, but in order
MV> to fit all of them in 1MB together with a menu program you'll
MV> probably have to compress them.

MM> Yep, if you remove the duplicates archived on funet, you'll get
MM> around 1,4 megabytes. When compressed with pucrunch, the whole lot
MM> takes about 8 kilobytes less than a megabyte.

Incidentally, that's just what you need for a little selection menu 8)

MM> There's no documentation on this particular project available.
MM> It's work in progress. The idea is to use a 1-megabyte ROM, maybe
MM> a MC 6821 PIA for bank switching, and some glue logic.

Is there a good way of getting the 6821 to a known default state on
powerup? If it's anything like the 6526 the PIA will be set to all
inputs and I guess you could just use a couple of pulldown resistors
to get them all to zero.

PS: if this projects gets to the stage where you make a couple of
    PCBs, I'd love to be in on it :)

    ___          .     .  .         .       . +  .         .      o   
  _|___|_   +   .  +     .     +         .   .  Per Olofsson, konstnär
    o-o    .      .     .   o         +
     -       +            +    .
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