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???
10/27/06 14:46
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#127054 - Reconfiguration
Responding to: ???'s previous message
It has been a long time, but as I recall one of the frustrating things about the 8255 was that if you reconfigured one of the ports (if I remember correctly, Port B from input to output), all the other ports returned to their default state (Port C from output to input). Any outputs that were in a particular state just lost their status.

-Aubrey

List of 61 messages in thread
TopicAuthorDate
Any value to a fast 8255?            01/01/70 00:00      
   Fast 8255            01/01/70 00:00      
      8255 breakeven volume            01/01/70 00:00      
         there are a few things ...            01/01/70 00:00      
            8255 vs 6824            01/01/70 00:00      
               too many users failed            01/01/70 00:00      
            Reconfiguration            01/01/70 00:00      
               Yes, one had to know how the device behaved.            01/01/70 00:00      
               the 8255 was tough to learn, but in its crummy way            01/01/70 00:00      
   peaple would rather forget the 8255            01/01/70 00:00      
      Why do you suppose that is, Jez?            01/01/70 00:00      
   raison d'etre            01/01/70 00:00      
      Main reason, I think            01/01/70 00:00      
         There are other reasons, too.            01/01/70 00:00      
            Thanks for sharing your experience!            01/01/70 00:00      
      There's also a large replacement part market.            01/01/70 00:00      
         but for that you have to compste with Intersil            01/01/70 00:00      
            Intersil still only offers the \'80\'s technology            01/01/70 00:00      
               May be I am wrong, but...            01/01/70 00:00      
                  It hasn't got the same sort of ports as the 805x            01/01/70 00:00      
                     Yes, you are right            01/01/70 00:00      
                     8255            01/01/70 00:00      
                        Why would a novice build a PCB?            01/01/70 00:00      
                           Products and packages            01/01/70 00:00      
                              gee ... and I've never before heard of Tekmos ...            01/01/70 00:00      
   quick thoughts            01/01/70 00:00      
      You're on the right track, EXCEPT ...            01/01/70 00:00      
   on analogy...            01/01/70 00:00      
   8255 in India            01/01/70 00:00      
      It makes little sense to teach 8085, or does it?            01/01/70 00:00      
         I Agree            01/01/70 00:00      
            Do not attend            01/01/70 00:00      
               Every Collage            01/01/70 00:00      
               Not "College Think"            01/01/70 00:00      
      just had a thought - Lynn, Jez            01/01/70 00:00      
         Enhanced 8255            01/01/70 00:00      
            If all one could get is PLCC ...            01/01/70 00:00      
         well i have come up with a way.            01/01/70 00:00      
            There is a problem with FPGA\'s ...            01/01/70 00:00      
               nRD is needed in the 8255 as a clock            01/01/70 00:00      
                  Perhaps that\'s because they use latches            01/01/70 00:00      
                     on using undefined states            01/01/70 00:00      
                        grounding chip select is risky            01/01/70 00:00      
                           but what if it is grounded?            01/01/70 00:00      
               clinging to the past            01/01/70 00:00      
                  Don't forget the Maxim/Dallas parts, they use 5V0            01/01/70 00:00      
                     as usual apples and oranges            01/01/70 00:00      
                        you need to see it from Richard's viewpoint            01/01/70 00:00      
                           he has the right to his viewpoint ...            01/01/70 00:00      
                              There's room for disagreement on that ...            01/01/70 00:00      
                        "development" and "replacement" are different            01/01/70 00:00      
                           well, for the (in)famous "universal board"            01/01/70 00:00      
                              If there's a market, it would be for THE part            01/01/70 00:00      
                                 again mixing parametres            01/01/70 00:00      
                                    the value of an improved 8255 in legacy applicatio            01/01/70 00:00      
                                       I'm not so sure about that one ...            01/01/70 00:00      
                                          OK that was just one - bad - example...            01/01/70 00:00      
                                             My point and point of view, all along has been ...            01/01/70 00:00      
                                    let's clear up some misconceptions ...            01/01/70 00:00      
      8085?            01/01/70 00:00      
         RE:8085?            01/01/70 00:00      

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