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???
07/25/05 12:27
Modified:
  07/25/05 13:16
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 		 #97984 - oh yes?
Responding to: ???'s previous message
it shouldn't require a pullup when driven from a CMOS device like these MCU's

"it shouldn't require a pullup when driven from a CMOS device"
shortened like this the statement is correct. "Standard: CMOS has a push-pull output which can supply the needed Voh at the needed Ioh.

"it shouldn't require a pullup when driven from a CMOS device like these MCU's"
is wrong. Since "standard" '51 derivatives are NOT push-pull but "Quasi-bidirectional" Voh is, for some typical derivatives, specified at 30-100 uA which hardly can support TTL.

Erik

List of 31 messages in thread
TopicAuthorDate
Help with Assembly Code            01/01/70 00:00      
   Just one question            01/01/70 00:00      
   REPLY            01/01/70 00:00      
      74HC244            01/01/70 00:00      
   Some Possibilities:            01/01/70 00:00      
   Don't be surprised ...            01/01/70 00:00      
      Do not use TABs!            01/01/70 00:00      
         Right, but I meant            01/01/70 00:00      
            in case of Keil            01/01/70 00:00      
               Sharp eye !            01/01/70 00:00      
   re:mehdi & don't be surprised            01/01/70 00:00      
      RC Reset!!!            01/01/70 00:00      
   could you explain            01/01/70 00:00      
   Port 1 output/input conflict.            01/01/70 00:00      
      port 0 assigned as output            01/01/70 00:00      
         hiding the point            01/01/70 00:00      
   RE: Input/Output port            01/01/70 00:00      
      infinite loop            01/01/70 00:00      
      port            01/01/70 00:00      
         terminology            01/01/70 00:00      
         re: Erik Malund            01/01/70 00:00      
            killing your '51            01/01/70 00:00      
               re: killing your '51            01/01/70 00:00      
                  Negative logic            01/01/70 00:00      
                  0 and 1            01/01/70 00:00      
            I know it is not "in" to read before act            01/01/70 00:00      
   Pullups?            01/01/70 00:00      
      Well ... maybe not with TTL ...            01/01/70 00:00      
         strictly speaking,for 74LS...            01/01/70 00:00      
         oh yes?            01/01/70 00:00      
   re: re: got it            01/01/70 00:00      

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