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Christoph Franck
02/20/12 06:14
Read: 537 times
Sindelfingen
Germany


 
#186061 - One more argument ...
Responding to: Andy Neil'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?      Christoph Franck      02/18/12 12:27      
   Sounds Like From What You Said...      Michael Karas      02/18/12 15:00      
      Didn't want to point fingers.      Christoph Franck      02/19/12 02:33      
         A?      JecksonS Ben      02/19/12 04:50      
            Don't forget AVR      Andy Neil      02/19/12 05:44      
               One more argument ...      Christoph Franck      02/20/12 06:14      
                  Independently testable      Per Westermark      02/20/12 11:00      
                     Slow but critical.      Christoph Franck      02/20/12 14:13      
                        Yes      Per Westermark      02/20/12 17:59      
                           ESD      Kai Klaas      02/21/12 05:38      
                               You can't      Per Westermark      02/21/12 06:04      
                                 You can...      Kai Klaas      02/21/12 06:27      
                                    But emi-filter, overvoltage protection etc may not be enough      Per Westermark      02/21/12 06:46      
                                       ESD ...      Kai Klaas      02/21/12 07:51      
                                          It's not just ESD, it's "the works"      Christoph Franck      02/21/12 08:47      
                                             I do not trust the watchdog...      Kai Klaas      02/21/12 09:44      
                                                The simpler, the more trustworthy.      Christoph Franck      02/21/12 11:08      
                                                   Less complex does not mean less probable to fail!      Kai Klaas      02/22/12 06:48      
                                                   WDT and debug breadcrumbs      Oliver Sedlacek      02/23/12 06:14      
                                                Lightning strikes      Kalpak Dabir      02/22/12 04:33      
                                                   A watchdog should never be needed - but should be there      Per Westermark      02/22/12 05:55      
                                                   A watchdog isn't a fuse...      Kai Klaas      02/22/12 07:19      
                                                      correction      Erik Malund      02/22/12 07:35      
                                                      I just can not agree with that reasoning      Per Westermark      02/22/12 08:02      
                                                         Oh please, don't...      Kai Klaas      02/22/12 17:04      
                                                            so?      Per Westermark      02/22/12 17:26      
                                                Why you need a watchdog      Oliver Sedlacek      02/23/12 04:07      
                                                   And even if you had perfect software and hardware ...      Christoph Franck      02/23/12 05:03      
                                                      Reset versus power cycle      Kai Klaas      02/23/12 05:34      
                                                         Mars Pathfinder      Christoph Franck      02/23/12 06:27      
                                                         many modern chips      Erik Malund      02/23/12 07:05      
                                                            The problem with bidirectional reset pins.      Christoph Franck      02/23/12 07:26      
                                                               The uC in question      Erik Malund      02/23/12 08:07      
                                                            Latchup      Per Westermark      02/23/12 07:29      
                                                               ONLY clocked circuits?      Erik Malund      02/23/12 08:15      
                                                                  That kitchen exhaust fan ...      Christoph Franck      02/23/12 08:42      
                                                            link...      Kai Klaas      02/24/12 05:01      
                                                               Sales talk      Per Westermark      02/24/12 05:55      
                                                   certified applications      Erik Malund      02/23/12 07:00      
                  Using external watchdog      Oliver Sedlacek      02/21/12 03:11      
                     It's a feature, actually.      Christoph Franck      02/21/12 04:16      
               Wet      JecksonS Ben      02/24/12 01:04      
   Featuritis...      Kalpak Dabir      02/20/12 19:14      
   Looking at it from another perspective      Jez Smith      02/23/12 22:38      

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