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???
09/01/06 19:10
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 		 #123532 - WHAT DERIVATIVE? WHAT VOLTAGE
Responding to: ???'s previous message
no answer till you furnish this
Derivative (with manufacturer and ALL numbers and letters)
size of capacitors to gnd from XTAL1 and XTAL2
Measured voltage on Vcc
how do you determine "There was no oscillation" check the ALE pin


I have tried different capacitors,there wasn't any difference.
If this is not 'flying leads' (in which case 20 MHz is too fast) and the caps and xtal are not located stupidly on the PCB (more than 1cm trace and all bets are off), then "tried different capacitors" is futile, just use the recommended size for the derivative.


Erik





List of 41 messages in thread
TopicAuthorDate
20 MHz osc.            01/01/70 00:00      
   no answer            01/01/70 00:00      
      by oscilloscope probe            01/01/70 00:00      
         WHAT DERIVATIVE? WHAT VOLTAGE            01/01/70 00:00      
            Why Erik is asking            01/01/70 00:00      
               Do standard i8052's work at 20 MHz?            01/01/70 00:00      
                  who c ares            01/01/70 00:00      
                     Maybe he don't know what a "derivative" is??            01/01/70 00:00      
         ALE probably won't help ...            01/01/70 00:00      
            it will            01/01/70 00:00      
               true enough, but he knows it\'s not oscillating            01/01/70 00:00      
                  you never know            01/01/70 00:00      
                     FET buffer is suited to touch the oscillator pins            01/01/70 00:00      
                        Or a FET probe for your 'scope            01/01/70 00:00      
                           Of course, but expensive...            01/01/70 00:00      
                              Yes, but necessary            01/01/70 00:00      
                                 Dont take it too literaly...            01/01/70 00:00      
                                    quite true            01/01/70 00:00      
                                       we'll never know            01/01/70 00:00      
                                 Ah, now I know what you mean!            01/01/70 00:00      
                                 Low capacitance probes.            01/01/70 00:00      
   That would be tricky...            01/01/70 00:00      
      Well            01/01/70 00:00      
   thanks for all replies,            01/01/70 00:00      
      8259            01/01/70 00:00      
      Operating?            01/01/70 00:00      
      Crystal Types            01/01/70 00:00      
         Xtal            01/01/70 00:00      
            ???            01/01/70 00:00      
               SMS reply            01/01/70 00:00      
                  Only NP0 ceramics must be used!            01/01/70 00:00      
                     I'm curious            01/01/70 00:00      
      Some answers...            01/01/70 00:00      
      no thanks            01/01/70 00:00      
      You really SHOULD respond            01/01/70 00:00      
         So many people SHOULD...            01/01/70 00:00      
            if only they WOULD            01/01/70 00:00      
   Use Inductor            01/01/70 00:00      
      Yes, but at the right place!            01/01/70 00:00      
         so why bother            01/01/70 00:00      
   and why bother #2            01/01/70 00:00      

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