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???
06/15/07 08:57
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 		 #140828 - where's the decoupling
Responding to: ???'s previous message
= a 100nF ceramic capacitor accross VCC and GND of the '51 (try to connect it directly next to the approprate legs of the chip). Also, a filtering electrolythics of say 100uF between VCC and GND. Your GND path seems to be too long and involve too many connections, too.

Some of these protoboards also like to develop bad contacts; try to avoid them. You'll be better off if you get a decent "precision" socket for the '51 and just carefully solder everything to the "legs" of the socket (be careful, the plastic used for the sockets melts too easily). A soldering-protoboard is even better.

For further serious work also consider getting the reset IC. It will spare you some headache, too.

JW


List of 46 messages in thread
TopicAuthorDate
have any one having the Strange prob with 89C51 ?            01/01/70 00:00      
   Post your code            01/01/70 00:00      
      ... and a photo...            01/01/70 00:00      
   "strange" problems have very often roots in...            01/01/70 00:00      
      Sir for Code here it is,            01/01/70 00:00      
         Here is code for Serial,            01/01/70 00:00      
            and what does it do, exactly?            01/01/70 00:00      
               The Problem is that,            01/01/70 00:00      
                  spurious resets            01/01/70 00:00      
                     Well sir,            01/01/70 00:00      
                        power supply is not only the transformer...            01/01/70 00:00      
                           Well Jan, no problem            01/01/70 00:00      
                              What ID?            01/01/70 00:00      
                        incorrect statement            01/01/70 00:00      
                           And whats that SUPERVISOR ?            01/01/70 00:00      
                              How to show the both sides of circuit ?            01/01/70 00:00      
                                 there is your problem            01/01/70 00:00      
                              supervisor = reset IC (roughly)            01/01/70 00:00      
                                 Here is the Pic of Circuit, :-)            01/01/70 00:00      
                                    where's the decoupling            01/01/70 00:00      
                                    The problem you will forever have till you throw y            01/01/70 00:00      
                                       stray capacitance            01/01/70 00:00      
                                          my point exactly            01/01/70 00:00      
                                    No burden caps?            01/01/70 00:00      
                                       no they are there            01/01/70 00:00      
         You need to set the Stack Pointer Register            01/01/70 00:00      
            SP            01/01/70 00:00      
               Clarification            01/01/70 00:00      
                  stack troubles            01/01/70 00:00      
                     dictionary definition of 'easier'            01/01/70 00:00      
                        something like that            01/01/70 00:00      
                           pray explain            01/01/70 00:00      
                              it's not going to solve the problem...            01/01/70 00:00      
                                 Oh yes            01/01/70 00:00      
                                    NO, where have you seen me saying that?            01/01/70 00:00      
                                    WoW what a nice idea ;-) i loved it,            01/01/70 00:00      
                                       so, why did you not \'dare\' to do so?            01/01/70 00:00      
                                          Why Not Sir :-) i am going to do it,            01/01/70 00:00      
   AT89C51            01/01/70 00:00      
   maybe this is your problem            01/01/70 00:00      
      Well is EA should be connected to VCC ?            01/01/70 00:00      
         read the datasheet            01/01/70 00:00      
            hey Charles you are Great :-)            01/01/70 00:00      
               why do you not dare to read the datasheet in the f            01/01/70 00:00      
         an editorial about a recurring issue            01/01/70 00:00      
   Thanks everybody, Problem solved ;-)            01/01/70 00:00      

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