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???
01/03/12 03:01
Modified:
  01/03/12 03:02
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 		 #185279 - RC RESET worked fine for years ,,, but ...
Responding to: ???'s previous message
With today's FLASH-based MCU's, there are other considerations.

First of all, until you know how long RESET has to persist, you can't use an RC. Secondly, until you know the relationship between Vcc and RESET, you can't use RC. Better take the advice of the guys who've done this before, and use what they recommend.

More important than that ... read and understand...fully... the datasheet for your particular MCU. Know its Voh, Vih, Iol, Ioh, etc.

The same goes for your LED. If you don't know how much current you need to make it glow, you can't very well choose a resistor, can you? You probably need to know how much current your MCU can source and sink, too.

RE


List of 32 messages in thread
TopicAuthorDate
AT89S52 and ISP problem            01/01/70 00:00      
   Quick Schematic Obversation            01/01/70 00:00      
      hmm            01/01/70 00:00      
         Your Reset Input            01/01/70 00:00      
            Thanks!!            01/01/70 00:00      
   Your schematic is wrong            01/01/70 00:00      
   The AT89S52 needs a reset chip!            01/01/70 00:00      
      The AVRISP-2 is a USB device            01/01/70 00:00      
   what an AWFUL design            01/01/70 00:00      
      Isn't mine!            01/01/70 00:00      
         Compare several schematics            01/01/70 00:00      
            Thanks!!            01/01/70 00:00      
               Sink or source? Does matter a lot!            01/01/70 00:00      
                  Not granted            01/01/70 00:00      
                     Processor can be used            01/01/70 00:00      
                        Yeah..            01/01/70 00:00      
                     cure for ignorance            01/01/70 00:00      
         you forgot the quotes            01/01/70 00:00      
         well            01/01/70 00:00      
            Funny            01/01/70 00:00      
               RC resets are evul            01/01/70 00:00      
                  So?            01/01/70 00:00      
                     Not necessarily,,,            01/01/70 00:00      
                     I guess you are a student / hobbyist            01/01/70 00:00      
                        Oh..            01/01/70 00:00      
                        Even or better just then...            01/01/70 00:00      
                           Where to apply 100nF?            01/01/70 00:00      
                              Shortest possible distance            01/01/70 00:00      
                        especially not for a hobbyist            01/01/70 00:00      
                  RC RESET worked fine for years ,,, but ...            01/01/70 00:00      
               no, not "will" but "is likely to"            01/01/70 00:00      
                  an added IMPORTANT comment            01/01/70 00:00      

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