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???
01/27/05 09:45
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#85903 - The unused pins
Hi.

In my new design these pins are not used:
TxD (11)
INT0 (12)
INT1 (13)
P1.5 (6)
P1.6 (7)
P1.7 (8)
Is it safe (from the noise immunity point of view) to leave them unconnected? Are I not supposed to pull them up via a 10K or something?
I know pins of ports 1, 2 and 3 have internal pull-up resistors. And I know I should program the unused pins as output, but let's imagine I simply can't program them as output!

Best.


List of 9 messages in thread
TopicAuthorDate
The unused pins            01/01/70 00:00      
   why?            01/01/70 00:00      
   unused            01/01/70 00:00      
      Poor 89C51            01/01/70 00:00      
   Leave them unconnected            01/01/70 00:00      
      Upon reset            01/01/70 00:00      
         Pins are high            01/01/70 00:00      
         use the facts            01/01/70 00:00      
   output - input            01/01/70 00:00      

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