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Thread: pull up resistors

  1. #1

    Default pull up resistors

    I am using an at89c2051.I heard that only metal film resistors must be used for pull up..
    Why is that :? :? :? Why cant ordinary be used??

  2. #2
    Senior Member Cyborg
    Join Date
    Sep 2004


    I never used metal film resistors on 89c2051 cpus, and they all worked fine.

    oh I recall that the RC Reset circuit of 89c2051 should have R>= 50K.
    usually we use 10K in all other 51 family cpus.

    please confirm from datasheet and use R>=50K i.e 62K or so.
    Otherwise in some cases the cpu stops working after an hour or so.

    " To get working ideas effectively, I try to fail as fast as I can. "
    Richard Feynman

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