Help in 8051 timer

Discussion in 'Embedded Systems and Microcontrollers' started by OSOO, Apr 23, 2014.

  1. OSOO

    Thread Starter Member

    Feb 19, 2014
    34
    0
    I want to ask you a question about using Timer as a counter for external events ..



    Does the timer counts the high to low pulses ? ,or it must be a low to high pulses ?



    I am currently using 89C51
     
  2. JohnInTX

    Moderator

    Jun 26, 2012
    2,348
    1,029
    According to Table 38: TMOD Register in the datasheet, when either timer/counter is configured for external counting, it counts negative-going i.e high->low transitions.
     
  3. OSOO

    Thread Starter Member

    Feb 19, 2014
    34
    0
    Okay Thanks
     
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