Date: 2002-10-02 18:07:36
On Wed, 02 Oct 2002 03:04:20 -0700 email@example.com wrote: >Hallo John, > >> Back in the old days, you'd use something like the 74LS682. > >or 688 > Ok I found it, it's exactly the chip I described that I wished I had, cool! The SN54/74LS682, 684, 688 are 8-bit magnitude comparators. These device types are designed to perform comparisons between two eight-bit binary or BCD words. All device types provide P = Q outputs and the LS682 and LS684 have P>Q outputs also. 8-BIT MAGNITUDE basically if the two 8bit numbers match, the q goes low. The other versions can do greater than as well. You could combine those of course for >= and <. So to answer my question, when both i/o1 and q are low your at the decoded address at $de00. But this is just a pulse and you would need a flipflop to toggle the LED on/off. Cool, I should try making it.. I think people could find some uses for this simple circuit.. of course with the user port this example is pointless right now. But you could add a chip like an ADC or ram and stuff. Get your free encrypted email at https://www.hushmail.com Message was sent through the cbm-hackers mailing list
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