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???
07/19/06 15:44
Modified:
  07/19/06 16:33
Read: times


 		 #120600 - Makes only 3 drivers per port
Responding to: ???'s previous message
Erik said:
by my calculations 4-5mA, is that 'enormous' in your neck of the woods?

Maximum total Iol per 8bit port is 15mA for a standard 80C52. So, only 3 such drivers could be driven per port.

Erik said:
who cares about reading a pin used as output. If you need to, your code is not particularily smart.

I wouldn't either, but nevertheless important to know.

Kai

List of 49 messages in thread
TopicAuthorDate
Driving 12 Volts relay by 5 Volts microcontroller            01/01/70 00:00      
   12v relay            01/01/70 00:00      
      This will not work properly!            01/01/70 00:00      
         well, it might            01/01/70 00:00      
         pullup?            01/01/70 00:00      
            Doable, but disadvantagous            01/01/70 00:00      
               language and a comment            01/01/70 00:00      
                  Makes only 3 drivers per port            01/01/70 00:00      
      12v relay            01/01/70 00:00      
   12V relay driver for 80C52            01/01/70 00:00      
      12V relay driver for 80C52            01/01/70 00:00      
      Analysis            01/01/70 00:00      
         sure.but why? this is \"grab bag values\"            01/01/70 00:00      
            Re: Analysis            01/01/70 00:00      
               basically they are 'bleeders'            01/01/70 00:00      
                  Choosing Bleeder resistor values            01/01/70 00:00      
                     Values Are design Specific            01/01/70 00:00      
                        how to calculate?            01/01/70 00:00      
                           what you are missing is that a transistor junction            01/01/70 00:00      
                           Two ways of calculation...            01/01/70 00:00      
                              Thank you very much!            01/01/70 00:00      
                                 Nearly....            01/01/70 00:00      
                                    BC556 base current direction...            01/01/70 00:00      
                                       Three currents arround the base...            01/01/70 00:00      
                                          Yes. Its clear for me now.            01/01/70 00:00      
                                             Was a pleasure...            01/01/70 00:00      
                                                So Nice of You. Thanks again!            01/01/70 00:00      
   Didn't search first            01/01/70 00:00      
      Everything is already here. That is not the point!            01/01/70 00:00      
         Maybe it IS the point            01/01/70 00:00      
            Please read again his post            01/01/70 00:00      
               He'd have seen other alternatives            01/01/70 00:00      
                  I give up...            01/01/70 00:00      
                     don't            01/01/70 00:00      
         faq            01/01/70 00:00      
            Beat me to it            01/01/70 00:00      
            freewheling            01/01/70 00:00      
               1n4148            01/01/70 00:00      
               Heaven, no!            01/01/70 00:00      
                  as usual, the global became specific            01/01/70 00:00      
                     That's why I...            01/01/70 00:00      
                  FAQ update            01/01/70 00:00      
                     Comment            01/01/70 00:00      
                        It's fixed now. Thanks.            01/01/70 00:00      
   Alternatives            01/01/70 00:00      
   yet another way            01/01/70 00:00      
      Trouble making            01/01/70 00:00      
   the case of fault            01/01/70 00:00      
      Some thoughts            01/01/70 00:00      

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