Re: VIC-20 Mikro Assembler

From: MagerValp (
Date: 2002-06-12 10:41:07

>>>>> "B" == john/lori  <> writes:

RB> May I suggest to have a look at:

B> piggy-backing also lets you put ram where the VIC can see it.

B> (I think Magervalp has this written up some where, doesn't he?)

In C= Hacking issue 20 I describe how to piggyback 16K internally.
Ruud was kind enough to send me some 2114 RAM so I started an article
on adding 3K visible for the VIC. Unfortunately I killed the 74LS133
while desoldering. There's something wrong with my VIC chip too, and I
haven't really had the time to fix it (anyone have a spare PAL mother-

From my notes:

To add 3K internally you piggyback 6 2114 on top of the internal ones
(UE2 + UD2 for the first K, UE3 + UD3 for the second, etc), use /RAM1
- /RAM3 (pins 1-3 on UC4) as chip selects, and cut /RAM1 - /RAM3 on
the 74LS133 (pins 4-6 on UD9).

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

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