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???
10/04/07 20:06
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 		 #145422 - more details please
Responding to: ???'s previous message
Richard Erlacher said:
I've observed that ALE, nRD, nPSEN, and, worst of all, nWR continue to occur after RESET is asserted on the two, (Dallas, and Philips) MCU's that I was using, though I did not pursue the matter at the time.

I in http://www.8052.com/forum/read.phtml?id=145271 said:
Oh, this is that first experiment you conducted I assume. I always wanted to hear more details about that (and, I would like you to ask you to try a couple of things, if you want to go back to this case).
But, first, you say that you "observed MCU activity during RESET asserted", does this mean that you had tied up a scope both to RESET and some of the RAM signals (say, the most interesting, /CS and/or /WE), and/or VCC; and recorded this activity? Any pictures, perhaps?




Richard Erlacher said:
I'm not sure what I could safely have done to "stop" anything from operating once RESET was asserted.
You can use the RESET signal to gate /CS of course, but, first of all, it is suspicious that the mcu did not stop memory access upon RESET, so that should be investigated first. Also the memory should be insensitive to any activity below its stated threshold - that's why are you using that very expensive sort of memory at all, isn't it. I'd suspect at first hearing that you don't supply the BBRAM and '1232 from the same supply branch as the mcu - but that's of course only a wild guess without seing the actual circuit. Can you please post schematics here?


Richard Erlacher said:
The only external logic components were two latches (HCT573) and an 'HCT00, along with that DS1232. The 'HCT00 produced the select and enable strobes to the two BBRAMs.

I don't understand what the purpose of the 'HCT00 gates are. Can you please post schematics of that part, too?

JW




List of 189 messages in thread
TopicAuthorDate
Reset Accuracy            01/01/70 00:00      
   Read This            01/01/70 00:00      
   throw it away!            01/01/70 00:00      
   That is the nature of RC resets!            01/01/70 00:00      
   Inhereted design            01/01/70 00:00      
   1st Lesson            01/01/70 00:00      
      P.S. Welcome            01/01/70 00:00      
      is IS an iteresting question, isn't it?            01/01/70 00:00      
         more on supervisor            01/01/70 00:00      
            same thing            01/01/70 00:00      
            Extendec ASCII Characters            01/01/70 00:00      
               That's cool Joe            01/01/70 00:00      
               Not ASCII            01/01/70 00:00      
               Beware - Your results may vary            01/01/70 00:00      
         Thoughts on RC Resets            01/01/70 00:00      
            Schmitt leaves problems?            01/01/70 00:00      
               even at startup you can get into trouble            01/01/70 00:00      
                  the decline and f.. naah rise of the \'51            01/01/70 00:00      
                     the lpc9xx is the glaring BAD example...            01/01/70 00:00      
                        it's not about NXP, though I woldn't forgive them            01/01/70 00:00      
                           it's far past that time...            01/01/70 00:00      
                     only partially so            01/01/70 00:00      
            not quite            01/01/70 00:00      
            Lynn ... can you see anything wrong with ...            01/01/70 00:00      
               how about shooting a sparrow with a RPG?            01/01/70 00:00      
                  You've got to ask yourself ...            01/01/70 00:00      
                     Which manufacturers?            01/01/70 00:00      
                        everybody is            01/01/70 00:00      
                           errare humanum est...            01/01/70 00:00      
                        It's up to us to see that they fix it!            01/01/70 00:00      
                  What's the point?            01/01/70 00:00      
                     I do noy 'believe' I KNOW.            01/01/70 00:00      
                        You can't prove a negative ...            01/01/70 00:00      
                           when it's been gone for 100,000 "unit hours"            01/01/70 00:00      
                              correction            01/01/70 00:00      
                                 How do you monitor this?            01/01/70 00:00      
                                    how stupid can you be            01/01/70 00:00      
                                       so YOU really haven't ever looked at any of them?            01/01/70 00:00      
                                          sure I did            01/01/70 00:00      
                                             it's just as I said ... YOU guess and ship ...            01/01/70 00:00      
                                                Same question            01/01/70 00:00      
                                                   You force them in your test fixture            01/01/70 00:00      
                                                that I do not want to do my job is an insult            01/01/70 00:00      
                                                   It's always about your ego, isn't it, Erik?            01/01/70 00:00      
                                                      adding insult to injury            01/01/70 00:00      
         make it opposite            01/01/70 00:00      
            Answer is wrong            01/01/70 00:00      
               No, is not!            01/01/70 00:00      
                  RE: No, is not!            01/01/70 00:00      
                     Oops.            01/01/70 00:00      
                        the "small embedded printf"...            01/01/70 00:00      
                           LED blinking            01/01/70 00:00      
                              LCD init delay            01/01/70 00:00      
            possibly (most likely) incorrect post            01/01/70 00:00      
      supervisor IC            01/01/70 00:00      
   Check reset Schematic and capacitor .            01/01/70 00:00      
      not necessarily            01/01/70 00:00      
   RC time            01/01/70 00:00      
      crystal frequency is a negligible problem            01/01/70 00:00      
      who cares            01/01/70 00:00      
         Not so fast, there, Pilgrim ...            01/01/70 00:00      
            reset toujours            01/01/70 00:00      
               correction            01/01/70 00:00      
                  I didn\'t know this is the price of a bit...            01/01/70 00:00      
                     the origin of the \'bit\'            01/01/70 00:00      
                        Almost but not quite ...            01/01/70 00:00      
                           wasn't that a gold coin?            01/01/70 00:00      
                  So you assert that that's the one that works?            01/01/70 00:00      
               What is this "reset problem" solved by supervisor            01/01/70 00:00      
                  the final effect is on peripherals not the micro            01/01/70 00:00      
                  not, "this" but all            01/01/70 00:00      
                     What did you mean to say, Erik?            01/01/70 00:00      
                        proof? many ways, here is an example            01/01/70 00:00      
                           I don't doubt any of that, but ...            01/01/70 00:00      
                              the skinny            01/01/70 00:00      
                                 just another reset-related story            01/01/70 00:00      
                        true reset-related stories            01/01/70 00:00      
                           Relevance?            01/01/70 00:00      
                              yes, relevance.            01/01/70 00:00      
                                 the second example ...            01/01/70 00:00      
                                    I gave you two SOLID examples            01/01/70 00:00      
                                       I agree with Erik and Jan            01/01/70 00:00      
                                          Start at the end ...            01/01/70 00:00      
                                          I just think you're all fooling yourselves ...            01/01/70 00:00      
                                       Vexing, perhaps. Solid? Not in the least!            01/01/70 00:00      
                                       What\'s so \"solid\" about an anecdote?            01/01/70 00:00      
                                          Who gives a hoot            01/01/70 00:00      
                                    let\'s put it in another way            01/01/70 00:00      
                                       Here\'s what I want from you ...            01/01/70 00:00      
                                          A particular experience            01/01/70 00:00      
                                 Just consider THIS thread ...            01/01/70 00:00      
                                    well, what about this            01/01/70 00:00      
                                       there's a difference between a fake and a fix            01/01/70 00:00      
                                          I believe you are the only one with that opinion            01/01/70 00:00      
                                             So, who has actually tested their product?            01/01/70 00:00      
                                                incoirrecrt            01/01/70 00:00      
                                    my experience with RC reset            01/01/70 00:00      
                                       Invalid conclusion            01/01/70 00:00      
                                          here is YOUR misconception            01/01/70 00:00      
                                             You\'ve got it wrong ...            01/01/70 00:00      
                                                I can recreate this            01/01/70 00:00      
                                                   maybe you can ...            01/01/70 00:00      
      IN1232N            01/01/70 00:00      
         something is wrong            01/01/70 00:00      
         MAX1232 is better!            01/01/70 00:00      
   What do you mean by "erratic and random"?            01/01/70 00:00      
   RE: something is wrong            01/01/70 00:00      
      Would you be please so kind...            01/01/70 00:00      
         RE: Would you be please so kind...            01/01/70 00:00      
            Hhm,...            01/01/70 00:00      
      What\'s the power supply doing at power-on?            01/01/70 00:00      
   8051 Family Reset Function            01/01/70 00:00      
      Power ON reset            01/01/70 00:00      
         defined power on            01/01/70 00:00      
            inadequate power supply            01/01/70 00:00      
               what does that have to do with            01/01/70 00:00      
                  it has everything to do with it.            01/01/70 00:00      
                     Reset            01/01/70 00:00      
                        ... and what does it do as Vcc decays?            01/01/70 00:00      
                           Defence            01/01/70 00:00      
                              You needn't defend the party line ...            01/01/70 00:00      
                                 correct if you are NOT using a supervisor            01/01/70 00:00      
                                    bidir reset, if there is an internal supervisor            01/01/70 00:00      
                                       Oh, that's what 'bidirectional' means here            01/01/70 00:00      
                                          how do you call that property?            01/01/70 00:00      
                                          Maybe that's your RESET problem!            01/01/70 00:00      
                                             i do not            01/01/70 00:00      
                                                You don't what?            01/01/70 00:00      
                                                   I am sorry, Richard            01/01/70 00:00      
                                                      You do that often ...            01/01/70 00:00      
                                    lower            01/01/70 00:00      
                                    IF you're using too weak a PSU            01/01/70 00:00      
                                       another red herring            01/01/70 00:00      
                                          Well maybe it's not a red herring after all            01/01/70 00:00      
                              Ricxhard, posted            01/01/70 00:00      
                                 supervisor is irrelevant during Vcc decay            01/01/70 00:00      
                                    BULLSHIT            01/01/70 00:00      
                                       I've observed it, while you haven't even looked            01/01/70 00:00      
                     unpredictible is a strong word            01/01/70 00:00      
                        just how would YOU predict the behavior, Jan?            01/01/70 00:00      
                           CMOS            01/01/70 00:00      
                              Yes, that's fine ... well, maybe ...            01/01/70 00:00      
                     male cow manure            01/01/70 00:00      
                        and what's the value of the internal pulldown?            01/01/70 00:00      
               ... and who\\\'ll pay the bills?            01/01/70 00:00      
                  Not only that, but...            01/01/70 00:00      
                  It's too costly if it doesn't work            01/01/70 00:00      
                     get me a muckraker and a pair of boots            01/01/70 00:00      
                        Well, I've observed it, and you haven't even tried            01/01/70 00:00      
      Flash micros need a different treatment!!!            01/01/70 00:00      
         to Kai KISS            01/01/70 00:00      
            Of course, good alternative!            01/01/70 00:00      
         Why do the manufacturers not say that?            01/01/70 00:00      
            one is one            01/01/70 00:00      
            we have answered this many many times before            01/01/70 00:00      
               we really don't disagree ... at least on this            01/01/70 00:00      
                  sure you can            01/01/70 00:00      
            The same story again and again and again...            01/01/70 00:00      
               Clearly, we see things differently            01/01/70 00:00      
                  We aren't so differently...            01/01/70 00:00      
                     I have pulled every string I have ....            01/01/70 00:00      
                        That would be really awesome!!            01/01/70 00:00      
                     it would be awesome            01/01/70 00:00      
                        then I'll call the whole thing off            01/01/70 00:00      
                           No, that's not it            01/01/70 00:00      
                              Would this solve your problem?            01/01/70 00:00      
                                 What do you mean?            01/01/70 00:00      
                                    more details please            01/01/70 00:00      
                                       Maybe this answers some questions            01/01/70 00:00      
                                          Blocking the BBRAMs            01/01/70 00:00      
                                             Why?            01/01/70 00:00      
                                                certainly            01/01/70 00:00      
                                                You asked for a methode, and I showed you one            01/01/70 00:00      
                                                   I agree, what you suggest might work            01/01/70 00:00      
                                                      slowpoke            01/01/70 00:00      
                                                      Because of the enormous currents?            01/01/70 00:00      
                                                         I considered that ...            01/01/70 00:00      
                                                            Of course!!            01/01/70 00:00      
                                                               I've been looking for simple ways            01/01/70 00:00      
                                                more suspition - and more questions            01/01/70 00:00      
                                                   It wasn't a thorough test            01/01/70 00:00      
                                          more questions...            01/01/70 00:00      
                                             I don't understand the questions ...            01/01/70 00:00      
                                                the questions are intended...            01/01/70 00:00      
                                                   there are a number of forces at work here            01/01/70 00:00      
                        Take care....            01/01/70 00:00      
                           You pointed that out once before ...            01/01/70 00:00      
                        We did, of course!            01/01/70 00:00      
                           That\'s probably an adequate statistical basis            01/01/70 00:00      

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