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???
06/13/08 14:56
Modified:
  06/13/08 14:58
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 		 #155865 - a strange thing has happened
Responding to: ???'s previous message
I have included a 470uF electrolytic capacitor near the supply (supply to ground) to short ant high frequencies. Yes both PSEN and RST switches are the normally open type.

"how about checking without the processor? short the RXD and TXD pins at the CPU socket and then do the same test as before to make sure that the signals are not lost enroute to the cpu and back", done that, signals are ok.

Uh, mates I noticed something, virtually all of port 2 gets shorted to ground upon start up. is that normal? I'm going to check the same 89c51 chip on my trainer board to make sure



List of 45 messages in thread
TopicAuthorDate
I'm getting insane! pls help!            01/01/70 00:00      
   I do not know much about Arghmel, but            01/01/70 00:00      
      >Arghmel<, Erik, are you crazy?            01/01/70 00:00      
         fair warning to all            01/01/70 00:00      
   Thanks for the props but....            01/01/70 00:00      
      have you tried changing the chip            01/01/70 00:00      
   Yep            01/01/70 00:00      
      the Arghmel users should wake up soon            01/01/70 00:00      
         The Problem Often Is The ...            01/01/70 00:00      
            I'll try that            01/01/70 00:00      
               But....            01/01/70 00:00      
                  What breed of MAX232?            01/01/70 00:00      
                     so...            01/01/70 00:00      
                        Trainer Board            01/01/70 00:00      
                           um quite similar...            01/01/70 00:00      
                        Your schema looks fine            01/01/70 00:00      
                           a strange thing has happened            01/01/70 00:00      
                              470uF            01/01/70 00:00      
                                 Just wanted to state the same            01/01/70 00:00      
                              It would have to be a very good 470uF cap ...            01/01/70 00:00      
                                 Richard??            01/01/70 00:00      
                                    What negative effect would that be?            01/01/70 00:00      
                                       let's do that, you start            01/01/70 00:00      
                        DEAD wrong            01/01/70 00:00      
   Oh uh......            01/01/70 00:00      
      Wrong Xtal may be            01/01/70 00:00      
         0.1uF ok then            01/01/70 00:00      
            Are you sure?            01/01/70 00:00      
               I found a usable one            01/01/70 00:00      
                  Did you find the reason            01/01/70 00:00      
                     still searching for the reason            01/01/70 00:00      
            Model of a capacitor            01/01/70 00:00      
         18.432MHz for Std Baud Rates ...            01/01/70 00:00      
   Shorts,shorts,shorts,            01/01/70 00:00      
      Pictures?            01/01/70 00:00      
         why is that?            01/01/70 00:00      
            Just Curious            01/01/70 00:00      
               Hey uh Jon i had already removed all socketed ICs            01/01/70 00:00      
      Vss for logical chips SHOULD be ground            01/01/70 00:00      
         Stupid me, i meant Vcc not Vss            01/01/70 00:00      
         Let\'s call this a day            01/01/70 00:00      
            Good Luck!            01/01/70 00:00      
               Thank you all            01/01/70 00:00      
   Boot loader running?            01/01/70 00:00      
      I'll try it tonight            01/01/70 00:00      

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