Is It Possible To Set Timer/Counter In Microcontroller Externally By Using Some Physical Device ?

I would like to know whether it is possible to set timer/counter using external hardware? how ?

What I want is : I tweak the external hardware & timer is set to say [HASHTAG]#xxxxH[/HASHTAG]. Now,I again do minor modification & timer changes to [HASHTAG]#yyyyH[/HASHTAG].
Like this I would like to set 15-20 timer values which is changed as per change in external hardware. Is it possible ? How?


  • J Biswas
    J Biswas
    Many possible way to solve this. A few listed below:
    1) Use external controller - pump out desired values to external controller via standard available protocols I2C, UART, SPI etc. count as needed, pulse out on timer expiry.
    2) Use 4060 IC produce pulse as desired to start / restart timers
    3) Use 555 as monostable

    - JB -
  • Abhishek Rawal
    Abhishek Rawal
    @#-Link-Snipped-# Can you explain me in detail that how can I use IC555-Monostable to set timer value.
    Note that, I want microcontroller to automatically input different timer value as I tweak the external hardware connected to microcontroller. I am not talking about just setting & clearing timer flag for one time, but more than 15 times & also note that everytime after signal from timer flag is fetched, next timer/counter value which is set is not equal to previous one.
  • J Biswas
    J Biswas
    If you are well verse with uCs then use 1).
    Using 2) and 3) will require hardware design and iterated timing calibration.
    Sorry, we can only validate or help your circuit modification on 2) and 3) but will not be able to share design.
  • Jeffrey Arulraj
    Jeffrey Arulraj
    Why not use the Programmable Interval timers like Intel 8253 AND INTEL 8254 counters. They can be used along with your uC.

    When a Hardware is connected pull an interrupt. This interval will initialise the counter and you have various time periods that can be included easily Based on your need
  • a.alandkar
    Look take GPIO pins as an input pins. Check which pin is selected and According to the selection of pin set internal s/w to set the particular timer.

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