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???
03/17/07 14:52
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 		 #135166 - Unable to use P0 and P2
Hello,

This is my first time working with a 8052 compatible chip, and I apologise if the question is stupid, but I haven't found an answer yet.

My problem is that I cannot use the ports P0 or P2 (and the two highest bits of P3), even though I haven't connected any external memory, and I never use the instructions MOVX or MOVC. In addition, the EA pin is connected to Vcc.

If I try to write a new value to P0, for example, the instruction is apparently ignored.

I suppose there must be another pin besides EA to configure this behaviour, but I haven't found any information about it.

Do you have any idea?

Thanks in advance.
Mikel


List of 29 messages in thread
TopicAuthorDate
Unable to use P0 and P2            01/01/70 00:00      
   How do you detect that it's ignored?            01/01/70 00:00      
      Philips 80C52            01/01/70 00:00      
         Re: 80xxx            01/01/70 00:00      
         External memory?            01/01/70 00:00      
            Re: External memory?            01/01/70 00:00      
               Check the datasheet!            01/01/70 00:00      
                  More information            01/01/70 00:00      
                     80C52            01/01/70 00:00      
                        I think it does have internal ROM            01/01/70 00:00      
                           oops!            01/01/70 00:00      
         ICE or Eprom Emulator ?            01/01/70 00:00      
            It is an in-circuit emulator            01/01/70 00:00      
   my assumption            01/01/70 00:00      
      I'm afraid it can't be            01/01/70 00:00      
         There's a special "once" mode ... for emulators            01/01/70 00:00      
         try this            01/01/70 00:00      
            Re: try this            01/01/70 00:00      
               My guess            01/01/70 00:00      
                  Read the datasheets and read the posts, Mike            01/01/70 00:00      
            How is all this supposed to help?            01/01/70 00:00      
               It has code space...            01/01/70 00:00      
                  Where did you get that nonsense, Mike?            01/01/70 00:00      
   My conclusion:            01/01/70 00:00      
      What has it to do with the original question?            01/01/70 00:00      
   I do not know your emulator, but            01/01/70 00:00      
      My conclusion (and thanks for everyone)            01/01/70 00:00      
         then why not say so            01/01/70 00:00      
         Emulator            01/01/70 00:00      

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