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???
06/14/05 13:17
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#94883 - Has been discussed before
Responding to: ???'s previous message

This has been discussed before (I'm too lazy to dig out the item!). I dare say you'll find the voltage accuracy of the external supervisors a little bit better than the on chip micro ones. Depends on the criticality of your application. Obviously having a micro with these built in features is normally an advantage (when the actual silicon works as it should) and can save some board space and a few $$. In a safety critical application, you might want to use an external supervisor to add some reliability factor.

Atmel calls it a hardware watchdog simply because they have logic that performs the function - separate to the logic of the micro as you would for an external watchdog.

As to why you would use a tantalum capacitor for the RC reset as compared to a ceramic or film capacitor - I'll leave that to debate.

List of 25 messages in thread
TopicAuthorDate
AT89C51RD2 without supervisor IC            01/01/70 00:00      
   RC is never good            01/01/70 00:00      
      watchdog ad absurdum            01/01/70 00:00      
         and uses a bunch of pins            01/01/70 00:00      
            wd            01/01/70 00:00      
               paranoia revisited - wd 2            01/01/70 00:00      
                  when the full story            01/01/70 00:00      
                     WD3            01/01/70 00:00      
                        if code run astray            01/01/70 00:00      
   Has been discussed before            01/01/70 00:00      
   External ones are better            01/01/70 00:00      
      External ones are better in one respect            01/01/70 00:00      
         Yes, but...            01/01/70 00:00      
            Nope, never use an external when            01/01/70 00:00      
               Exactly!            01/01/70 00:00      
            Combined Watchdogs            01/01/70 00:00      
      External better in another respect            01/01/70 00:00      
   I'm using the internal and works well            01/01/70 00:00      
      works well - how do you know            01/01/70 00:00      
         who should test it?            01/01/70 00:00      
   nobody            01/01/70 00:00      
      the manufacturer should            01/01/70 00:00      
      Design Verification            01/01/70 00:00      
         one off            01/01/70 00:00      
      The meaning of "well"            01/01/70 00:00      

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