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???
08/10/06 21:16
Modified:
  08/10/06 21:19
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 		 #121999 - Add some pull up resistors (4.7K\'s) on LS device.
Responding to: ???'s previous message
Hello Tercio,

You said:
But i have just 74LSxxx buffers...there is some problem?
Someone can help-me?!

If all you have is 74LS devices you probably can make it work by adding pull up resistors (4.7K's) on the outputs. The LS device is only putting out highs of 2.7 Vdc and that is not enough. You will need outputs of 5.0 Vdc. I have had the same problems with MANY programmers I have built and this fixed THEM.

Regards,

Charles Bannister

Ps Your English is good enough.

List of 53 messages in thread
TopicAuthorDate
AT89s52 error with programmers            01/01/70 00:00      
   the 'weekly' question get the weekly answer            01/01/70 00:00      
   Add some pull up resistors (4.7K\'s) on LS device.            01/01/70 00:00      
      risque business            01/01/70 00:00      
   Home made JTAG            01/01/70 00:00      
      It is so refreshing to see thing like this instead            01/01/70 00:00      
         Tested!            01/01/70 00:00      
            have you 'tested' that the flash caps are fully            01/01/70 00:00      
               Atmel does that            01/01/70 00:00      
                  I think you are wrong            01/01/70 00:00      
                     I don't think so            01/01/70 00:00      
                        yes, and no            01/01/70 00:00      
                           Bah, shoot that designer :-)            01/01/70 00:00      
                              not the chip designer            01/01/70 00:00      
                                 JTAG x Flash Data Retention            01/01/70 00:00      
                                    nope            01/01/70 00:00      
   Tnx for answers...!            01/01/70 00:00      
   89s52 programmer            01/01/70 00:00      
      Only LS chips            01/01/70 00:00      
         there is the mail            01/01/70 00:00      
            here is world´s end            01/01/70 00:00      
               However far it from nowhere, I am sure you have ma            01/01/70 00:00      
                  You can buy here!            01/01/70 00:00      
                     he can do it himself...            01/01/70 00:00      
            What more fast than 9 ns?!            01/01/70 00:00      
               I do not understand. What I said is not to find s            01/01/70 00:00      
         Then stop doing in electronics!            01/01/70 00:00      
   re: AT89S52 error            01/01/70 00:00      
   Somebody test buffer CD4010?            01/01/70 00:00      
      the CD40 is sloooooooow compared to HC            01/01/70 00:00      
         What more fast than 9 ns?!            01/01/70 00:00      
            Not the speed is reason only            01/01/70 00:00      
   But and the pull ups in buffer´s out?            01/01/70 00:00      
      Does that suggest anything to you?            01/01/70 00:00      
      Type "74VHC244" into the search window            01/01/70 00:00      
         show the calculations            01/01/70 00:00      
      Schematic of programmer using 74LS244            01/01/70 00:00      
         Circuit that i am using            01/01/70 00:00      
            the very reason            01/01/70 00:00      
               Right...!            01/01/70 00:00      
                  have you conmsidered a 'radical' approach            01/01/70 00:00      
                     RX2...?!            01/01/70 00:00      
                        Rx2            01/01/70 00:00      
            Try this one            01/01/70 00:00      
               a full circle            01/01/70 00:00      
                  Time for a decision...            01/01/70 00:00      
               I did it...!            01/01/70 00:00      
                  Can\'t you order the parts by mail?            01/01/70 00:00      
      the old STUPID "It is tested"            01/01/70 00:00      
         Gee, another BS answer from Erik.            01/01/70 00:00      
            I can BE QUITE specific about what I post            01/01/70 00:00      
         "tested" does not mean tested            01/01/70 00:00      
            and even then ...            01/01/70 00:00      

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