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Richard Erlacher
09/20/14 17:40
Read: 896 times
Denver, Co

#190356 - Have you read the datasheet?
Responding to: Aamir Ali's previous message
PSEN is an output which enables external memory. You need to figure out why the MCU believes it is executing code in external memory.

EA is a control input telling the MCU to use external memory. You should tie it to the appropriate level, as indicated in the datasheet. Keep in mind that information that's valid for one MCU may not be applicable to another.

The datasheet will tell you whether you need to pull up the PSEN pin, though it's normally not needed. As Erik has told you, the PSEN may be telling you that your program has gone off into the weeds.


List of 7 messages in thread
PSEN outputting freq/code does not run      Aamir ALi      09/16/14 11:46      
   check EA and Pgm      Jim Granville      09/16/14 17:01      
      Done checking already      Aamir ALi      09/16/14 23:07      
   dollars to doughnots I bet      Erik Malund      09/17/14 15:10      
      any other reason/remedy      Aamir ALi      09/19/14 03:25      
         Reset circuit      Mahmood Elnasser      09/19/14 14:41      
         Have you read the datasheet?      Richard Erlacher      09/20/14 17:40      

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