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???
03/11/10 17:22
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 		 #174001 - No, I meant the /EW pin
Responding to: ???'s previous message
This /EW pin is specific to the 80C552.

Some of the micro's pins are read during power-on. These pins must not be changed afterwards! Unfortunately, the datasheets do not mention precisely which of this pins are treated in this way, so I can only guess, that this /EW pin might be of this sort.

To disable a watchdog by software makes no sense at all, because an ill running micro could jump to the corrsponding code line and eroneously disable the watchdog by itself!

A watchdog, which can be disabled by software is as sensless as an empty fire extinguisher, to remember Neil Kurzman's metaphor.

Kai Klaas

List of 55 messages in thread
TopicAuthorDate
Micro freeze            01/01/70 00:00      
   I don't understant how micro can freeze            01/01/70 00:00      
   Hang-up or lock-up?            01/01/70 00:00      
   details            01/01/70 00:00      
      You didn't answer the question            01/01/70 00:00      
      Oops, no good at all!            01/01/70 00:00      
      I think what Kai meant was /EA not EW            01/01/70 00:00      
         No, I meant the /EW pin            01/01/70 00:00      
   RST Watchdog            01/01/70 00:00      
      Add diagnostics            01/01/70 00:00      
         That's a good plan ... IF ...            01/01/70 00:00      
            Useful, but not essential            01/01/70 00:00      
               His problem, however ...            01/01/70 00:00      
                  Sorry - missing the point            01/01/70 00:00      
   more details            01/01/70 00:00      
      Don't jump to conclusions            01/01/70 00:00      
         test suggestions            01/01/70 00:00      
            Unlikely to be "random"            01/01/70 00:00      
            Assume nothing! Be very meticulous in your observations            01/01/70 00:00      
               somes evidences            01/01/70 00:00      
                  /EW not /WE!            01/01/70 00:00      
                     /EW not /WE            01/01/70 00:00      
                        that was my confusion, not yours ...            01/01/70 00:00      
                           The Watchdog does not "find" anything            01/01/70 00:00      
                              feed the dog            01/01/70 00:00      
                                 watchdog management            01/01/70 00:00      
                                 Many ideas out there . . .            01/01/70 00:00      
                              Certainly, but it responds to a missing "kick"            01/01/70 00:00      
                                 True, but            01/01/70 00:00      
                                    One simple diagnostic tool            01/01/70 00:00      
                     Oops! Begging your pardon ...            01/01/70 00:00      
   logic analyzer            01/01/70 00:00      
      Could be tricky...            01/01/70 00:00      
         someone doesn't want him to fix it            01/01/70 00:00      
            It isn't clear...            01/01/70 00:00      
         "potted" = what?            01/01/70 00:00      
            got it: "potted" = "drowned in resin"            01/01/70 00:00      
               potting SMD components            01/01/70 00:00      
   Limit Watchdog feed            01/01/70 00:00      
      I would like to write a more suitable code for this algorith            01/01/70 00:00      
         Keil example            01/01/70 00:00      
            The point is...            01/01/70 00:00      
      feed the watchdog in main loop            01/01/70 00:00      
         Non blocking loop            01/01/70 00:00      
            nothing impossible            01/01/70 00:00      
               Breaks on vacation?            01/01/70 00:00      
                  oops            01/01/70 00:00      
            Not at all!            01/01/70 00:00      
               big enought            01/01/70 00:00      
                  Both!            01/01/70 00:00      
                     re both            01/01/70 00:00      
                        You misunderstand            01/01/70 00:00      
         where to feed watchdog            01/01/70 00:00      
            You misunderstand            01/01/70 00:00      
            Watchdog kick in interrupts can often fail badly            01/01/70 00:00      

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