Re: Software 6502-on-6502, decoding address

From: John (
Date: 2002-10-02 10:12:59 writes:

>A question: how would one construct a circuit to toggle an LED everytime
>$dfdf was accessed?

Back in the old days, you'd use something like the 74LS682.  Feed it two
8-bit numbers, and it would tell you if they are equal.  There was
another that matched 12 bits (or was it more?) against a constant.
Quite clever - rearrange the bits so that all of the ones are at one
end, then just tell it how many there are.  But I can't remember the
number, and can't find it anywhere.

These days, the answer to just about every digital design question is
either a GAL (or other programmable logic), or a microcontroller.


       Message was sent through the cbm-hackers mailing list

Archive generated by hypermail 2.1.4.