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???
06/09/06 08:07
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 		 #118077 - PC817
Responding to: ???'s previous message
PC817 and other phototransistor-based amplifier-less optocouplers are a crap when it comes to higher speeds - good only up to 9600bps. Also, is it really the Sharp PC817 you are using - brand matters here. You will find different figures in datasheet perhaps, but read the datasheet carefully and you will find out it is NOT valid for normal usage in "digital" circuits.

So, this shows us - and I hope to you too - how it does not pay out to believe that you are smart enough. I asked you in http://www.8052.com/forum/read.phtml?id=117900 what type of optocoupler are you using; if you'd answer me rather than being rude with Andy, I'd tell you immediately that PC817 is a crap and you could save a day or so. Even if you would do what Andy suggested you and read carefully what's on the web, you'd find articles explicitly saying that you need to be careful with the optocoupler.

I still feel you owe Andy an apologize.

Jan Waclawek


List of 41 messages in thread
TopicAuthorDate
AT89S8252 MIDI Baud Rate            01/01/70 00:00      
   Have you ...            01/01/70 00:00      
      A 12 MHz xtal ...            01/01/70 00:00      
         why deprioritize what can not happen?            01/01/70 00:00      
         AT89S8252 MIDI Baud Rate            01/01/70 00:00      
            AT89S8252 MIDI Baud Rate            01/01/70 00:00      
            My settings from the 80's            01/01/70 00:00      
                I don't see Initialization Problem            01/01/70 00:00      
                  First results            01/01/70 00:00      
                     This could have problems            01/01/70 00:00      
                        strange behaviour            01/01/70 00:00      
                           indentions            01/01/70 00:00      
                           post the .lst or hex            01/01/70 00:00      
                              hex code and problem location            01/01/70 00:00      
                                 6N138            01/01/70 00:00      
                                 PC817            01/01/70 00:00      
                                    Debugging            01/01/70 00:00      
                                 had a look            01/01/70 00:00      
                                    rise/fall times (hair-splitting)            01/01/70 00:00      
                                       you cn't do that            01/01/70 00:00      
                                          PROBLEM SOLVED            01/01/70 00:00      
                                             Great Stuff - Glad it's working            01/01/70 00:00      
                                                next            01/01/70 00:00      
                                                Dark side of 
 tags      
      01/01/70 00:00      
                                                   What you are totally missing is t            01/01/70 00:00      
                                                   Interesting ..            01/01/70 00:00      
                                          if you look at me, you will know :)            01/01/70 00:00      
                  My settings from the 80's            01/01/70 00:00      
      Not a "standard" baud rate            01/01/70 00:00      
         Loop back would work because ...            01/01/70 00:00      
   Because it happens later ....            01/01/70 00:00      
   what is your hardware?            01/01/70 00:00      
      hardware            01/01/70 00:00      
         what optocoupler and what are the parts            01/01/70 00:00      
            emmeiG odoC            01/01/70 00:00      
               I was just about to make a suggestion            01/01/70 00:00      
               A suggestion            01/01/70 00:00      
                  Close            01/01/70 00:00      
                     No, by no means are you supposed to beg            01/01/70 00:00      
         Gimme Code            01/01/70 00:00      
         A SCOPE ???????            01/01/70 00:00      

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