Email: Password: Remember Me | Create Account (Free)

Back to Subject List

Old thread has been locked -- no new posts accepted in this thread
09/16/14 17:46
Read: times

#190350 - PSEN outputting freq/code does not run
I am using AT89C51, & xtal freq = 15Mhz.

1. I had checked ALE pin with CRO, it outputs: 15/5 = 2.5Mhz.
2. EA pin is +5V

3. Strange problem: PSEN pin is also outputting freq same as 2.5Mhz. So my code does not run.

I had checked for some shorting between two pins but found none.
Changed several micro but same problem.

Should I pull-up PSEN to +5V with 10K

List of 7 messages in thread
PSEN outputting freq/code does not run            01/01/70 00:00      
   check EA and Pgm            01/01/70 00:00      
      Done checking already            01/01/70 00:00      
   dollars to doughnots I bet            01/01/70 00:00      
      any other reason/remedy            01/01/70 00:00      
         Reset circuit            01/01/70 00:00      
         Have you read the datasheet?            01/01/70 00:00      

Back to Subject List