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???
03/02/07 17:51
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 		 #134118 - Let's be general
Responding to: ???'s previous message
Erik Malund said:
block the oscillator when the power is below 90% might be the answer to the power-down transient case.

I think that is a very good idea. ... This sure solves the problem of a runaway processor.

Lynn, pray explain what is the difference between a uC with the clock stopped and a uC held in reset. I know of two: in reset the port pins will be high, just stopping the clock will leave them where they were. Another issue: during a slow power down (draining the storage caps) how will the port pins behave if no reset but oscillator stopped.

Erik

PS: as opposed to Richard, I am discussing these new-fangled derivatives that are static CMOS, not the dynamic devices of yesteryear.


I'm not focused entirely on the old NMOS parts, Lynn. I'm looking for something that covers the general case. However, for now, I'm trying to define the problem(s). I've seen a case where the Philips 80C32, which clearly has no FLASH involved, runs away during/after reset. Because I do quite frequently, as a proportion of what I do with 805x's, have to deal with old-style circuits into which I want to drop new MCU's, I'm concerned with flash corruption, at least sometimes, and therefore need to know what the root of the runaway problem, as well as the flash corruption problem, is.

The reason I have this "bee under my bonnet" is that I've never seen a white-paper or other serious technical document dealing specifically with the problems associated with power transients and reset. The fact that I've been able to observe peculiar behavior such as the differences between power supply types, has piqued my interest. Now I'm considering building and running a test. Whether I actually do it is TBD.

RE




List of 147 messages in thread
TopicAuthorDate
Pierce oscillator runs down to Vcc=1.3V!            01/01/70 00:00      
   you should get a probing set...            01/01/70 00:00      
      I keep the micro always reseted, ...            01/01/70 00:00      
      we already know            01/01/70 00:00      
   Low voltage operation            01/01/70 00:00      
      What puzzles me ...            01/01/70 00:00      
         True Reset            01/01/70 00:00      
            Thanks, Lynn, for giving us this deep insight!            01/01/70 00:00      
               Scary warnings            01/01/70 00:00      
               do you not know ...            01/01/70 00:00      
         What I know about this...            01/01/70 00:00      
            I didn't hear complaints about reset back then            01/01/70 00:00      
               MAY???            01/01/70 00:00      
                  Those were different times            01/01/70 00:00      
                     which troubles?            01/01/70 00:00      
                        I don\'t understand your question, Oleg.            01/01/70 00:00      
                           If I could do that, I would be a millionaire from            01/01/70 00:00      
                           There is an overwhelming evidence!            01/01/70 00:00      
                              Conjecture, not Evidence            01/01/70 00:00      
                                 already answered            01/01/70 00:00      
                                    HORSEFEATHERS! ... Read the question            01/01/70 00:00      
                                       Do you put in question, that...            01/01/70 00:00      
                                          Comments on Vdd and Flash            01/01/70 00:00      
                                             not quite true            01/01/70 00:00      
                                                I agree...            01/01/70 00:00      
                                                   by the way            01/01/70 00:00      
                                                      state machine decoding...            01/01/70 00:00      
                                          well Richard did not read it            01/01/70 00:00      
                                             No, I did read it ... in fact, I read it long ago            01/01/70 00:00      
                                                of course you are not            01/01/70 00:00      
                                          reset etc.            01/01/70 00:00      
                                          stories-part II            01/01/70 00:00      
                                             aka experience            01/01/70 00:00      
                                                Another Low VDD Story            01/01/70 00:00      
                                                   That's how many reset chips work            01/01/70 00:00      
                                          about that I have no doubt ...            01/01/70 00:00      
                                       You, even less like to read the answers            01/01/70 00:00      
                                          As I said before ... HORSEFEATHERS!            01/01/70 00:00      
                                             a horse of a different color            01/01/70 00:00      
                                                Flogging a dead (reset?) horse            01/01/70 00:00      
                                                   would that not be the case of            01/01/70 00:00      
                                                      Not defective, just powered down            01/01/70 00:00      
                                                         then where is the difference            01/01/70 00:00      
                                                            Good chips and state machine failures            01/01/70 00:00      
                                                               Reset seems to be different with static 8052            01/01/70 00:00      
                                                                  What do you think about my lines, Lynn?            01/01/70 00:00      
                                                                     Static and Dynamic Reset, and Lines            01/01/70 00:00      
                                                                        Thanks, the hope dies last...            01/01/70 00:00      
                                                                        why?            01/01/70 00:00      
                                                                           Isn't it shocking...            01/01/70 00:00      
                                                                              I know a lot ...            01/01/70 00:00      
                                                                              ...partially...            01/01/70 00:00      
                                                                                 The names and functions            01/01/70 00:00      
                                                                                    the analogy            01/01/70 00:00      
                                                                     Flash and Lines            01/01/70 00:00      
                                                                        So, what the hell is the remedy, then??            01/01/70 00:00      
                                       So long post...            01/01/70 00:00      
                                          Kai's remarks are germane to the issue            01/01/70 00:00      
                                             Stoping the oscillator            01/01/70 00:00      
                                                Lynn, pray explain            01/01/70 00:00      
                                                   Stopped clocks and reset            01/01/70 00:00      
                                                      waitaminute....            01/01/70 00:00      
                                                         This leads to the conclusion that ...            01/01/70 00:00      
                                                            Some further reading            01/01/70 00:00      
                                                   Let's be general            01/01/70 00:00      
                                                      General Reset            01/01/70 00:00      
                                                         So ... how do we fix it?            01/01/70 00:00      
                                                            one thing you could do would be to ..            01/01/70 00:00      
                                                               Tying reset ot crystal enable            01/01/70 00:00      
                                                it's already there... well in some form...            01/01/70 00:00      
                                                   Clock stopping on power-up            01/01/70 00:00      
                                                      we have alternatives...            01/01/70 00:00      
                                             comments            01/01/70 00:00      
                                             reset (and diode)            01/01/70 00:00      
   trying to conclude            01/01/70 00:00      
      Total agree!            01/01/70 00:00      
         That's not quite been my experience            01/01/70 00:00      
      Erik ... That proves nothing!            01/01/70 00:00      
         what else do you want 'proven'            01/01/70 00:00      
            suggestion vs. proof            01/01/70 00:00      
               I need a link            01/01/70 00:00      
                  well, you do not need tp prove it            01/01/70 00:00      
                     I had not considered these ATMEL (yechh) parts            01/01/70 00:00      
                        is there no end?            01/01/70 00:00      
                           coincidence is not proof            01/01/70 00:00      
                              Why on earth would I do that?            01/01/70 00:00      
                                 I would make me do something            01/01/70 00:00      
                                    Sadly, few who are in a position to do something            01/01/70 00:00      
                                 I am not demanding proof because is isn't there.            01/01/70 00:00      
                                    Maybe you can get support from Silabs?            01/01/70 00:00      
                        All manufacturers have problems            01/01/70 00:00      
                           function, not the device            01/01/70 00:00      
                              I like the way you go into the details!            01/01/70 00:00      
                                 It puzzles me that no chip maker has done this.            01/01/70 00:00      
                                    Vdd slew rate as a factor.            01/01/70 00:00      
                                       I have looked, but since it is not one of 'my' der            01/01/70 00:00      
                                          1 ms Vdd slew rates            01/01/70 00:00      
                                             I'd be afraid...            01/01/70 00:00      
                                                nope            01/01/70 00:00      
                                                   if I specify the slew rate for powerdown...            01/01/70 00:00      
                                                No ... I see this as limiting board capcitance            01/01/70 00:00      
                                                   I know...            01/01/70 00:00      
                                                      they get what they deserve!            01/01/70 00:00      
                                                         be realistic            01/01/70 00:00      
                                                            it takes more than a supervisor            01/01/70 00:00      
                                                               shooting sparrows with RPGs            01/01/70 00:00      
                                                                  it's not a sparrow, Erik ... it's a vulture            01/01/70 00:00      
                                                                     as it does not, then why worry            01/01/70 00:00      
                                                                        Erik, I don't know where your head's wedged ...            01/01/70 00:00      
                                                                           An almost off-topic comment on Xilinx JTAG            01/01/70 00:00      
                                                                           there is no problem, so why do you state there is            01/01/70 00:00      
                                                                              ?            01/01/70 00:00      
                                                                                 calrification            01/01/70 00:00      
                                                                              If you would get your head out of your ...            01/01/70 00:00      
                                                                                 well, if you do not want to 'test' the derivatives            01/01/70 00:00      
                                                                                    If you want yours tested, YOU test 'em            01/01/70 00:00      
                                                                                       I did not            01/01/70 00:00      
                                                                                          It's like breaking off the Vcc pin            01/01/70 00:00      
                                                                                             the datasheet states..            01/01/70 00:00      
                                                                                                It's probably ATMEL (yechhh!) that said that            01/01/70 00:00      
                                                                                                rephrased to match this subject            01/01/70 00:00      
                                                               the bulletproof '51            01/01/70 00:00      
                                                                  Custom 8051!            01/01/70 00:00      
                                                                  That is not the goal.            01/01/70 00:00      
                                             very true ...            01/01/70 00:00      
                                          I don't understand, Erik ...            01/01/70 00:00      
                                             READ!!!!!!!!!!!!!!!!!!!!!            01/01/70 00:00      
                                                when SiLabs builds a DIP-40 or PLCC-44 805x            01/01/70 00:00      
                                                   what does the package have to do with slew rate            01/01/70 00:00      
                                                      Erik ... it has to do with what I'll test.            01/01/70 00:00      
                                                         well, if you restrict your test to ancients, then            01/01/70 00:00      
                                                            current parts, but in DIP40 or PLCC44            01/01/70 00:00      
                                                               well you may find that someone sinned but did            01/01/70 00:00      
                                       No manufacturer warns about slew rates!!            01/01/70 00:00      
                                          actually I recall one            01/01/70 00:00      
                           I reread the whole link and            01/01/70 00:00      
                              To Richard            01/01/70 00:00      
                              it's just "lip-service" and means nothing            01/01/70 00:00      
               Please, Richard, only facts            01/01/70 00:00      
                  Kai, you can\'t compare the two environments            01/01/70 00:00      
   re 'lip service'            01/01/70 00:00      
      there you go again ...            01/01/70 00:00      
         unless the chairman of the board confess his sin            01/01/70 00:00      
            What you\'re spewing is nonsense            01/01/70 00:00      
               show what nonsesne you are communicating            01/01/70 00:00      
   what is this still about?            01/01/70 00:00      
      Times change, and so do IC's...            01/01/70 00:00      

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