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???
02/20/12 13:14
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 		 #186061 - One more argument ...
Responding to: ???'s previous message
... to support the use of an external watchdog then.

"The internal watchdog has two dozens of ways to configure it (timeout, type of reset, etc), and its critical failure mode is well documented in the datasheet (once you piece together snippets of information from various locations). It's nice, it's shiny, it's convenient, it works (and fails) exactly as specified in the datasheet."

IMHO the "ideal" watchdog should require a clock only for resetting, not for reaching its timeout. If that means that I can't chose the timeout in 4096 steps between 1ms and 16s, then I'd happily trade this small inconvenience for a watchdog that isn't going to lock up with the rest of the chip.

List of 44 messages in thread
TopicAuthorDate
Pointless watchdog?            01/01/70 00:00      
   Sounds Like From What You Said...            01/01/70 00:00      
      Didn't want to point fingers.            01/01/70 00:00      
         A?            01/01/70 00:00      
            Don't forget AVR            01/01/70 00:00      
               One more argument ...            01/01/70 00:00      
                  Independently testable            01/01/70 00:00      
                     Slow but critical.            01/01/70 00:00      
                        Yes            01/01/70 00:00      
                           ESD            01/01/70 00:00      
                               You can't            01/01/70 00:00      
                                 You can...            01/01/70 00:00      
                                    But emi-filter, overvoltage protection etc may not be enough            01/01/70 00:00      
                                       ESD ...            01/01/70 00:00      
                                          It's not just ESD, it's "the works"            01/01/70 00:00      
                                             I do not trust the watchdog...            01/01/70 00:00      
                                                The simpler, the more trustworthy.            01/01/70 00:00      
                                                   Less complex does not mean less probable to fail!            01/01/70 00:00      
                                                   WDT and debug breadcrumbs            01/01/70 00:00      
                                                Lightning strikes            01/01/70 00:00      
                                                   A watchdog should never be needed - but should be there            01/01/70 00:00      
                                                   A watchdog isn't a fuse...            01/01/70 00:00      
                                                      correction            01/01/70 00:00      
                                                      I just can not agree with that reasoning            01/01/70 00:00      
                                                         Oh please, don't...            01/01/70 00:00      
                                                            so?            01/01/70 00:00      
                                                Why you need a watchdog            01/01/70 00:00      
                                                   And even if you had perfect software and hardware ...            01/01/70 00:00      
                                                      Reset versus power cycle            01/01/70 00:00      
                                                         Mars Pathfinder            01/01/70 00:00      
                                                         many modern chips            01/01/70 00:00      
                                                            The problem with bidirectional reset pins.            01/01/70 00:00      
                                                               The uC in question            01/01/70 00:00      
                                                            Latchup            01/01/70 00:00      
                                                               ONLY clocked circuits?            01/01/70 00:00      
                                                                  That kitchen exhaust fan ...            01/01/70 00:00      
                                                            link...            01/01/70 00:00      
                                                               Sales talk            01/01/70 00:00      
                                                   certified applications            01/01/70 00:00      
                  Using external watchdog            01/01/70 00:00      
                     It's a feature, actually.            01/01/70 00:00      
               Wet            01/01/70 00:00      
   Featuritis...            01/01/70 00:00      
   Looking at it from another perspective            01/01/70 00:00      

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