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Which Microcontroller To Use For A Frequency Counter

Discussion in 'Microcontrollers, Programming and IoT' started by radiotek, Apr 22, 2013.

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  1. radiotek

    radiotek

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    May 31, 2011
    There are so many different type and families of microcontrollers out there it makes it very difficult to decide which one to buy. There are 8 bit, 16 bit and 32 bit controllers and so many different manufacturers making these chips it really makes it confusing which one to use for your project. I will need a microcontroller that will be able to count frequencies to at least 40 Mhz. Any suggestions or help would be appreciated.
    Frank
     
  2. BobK

    BobK

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    Jan 5, 2010
    I can only speak about PICs. Only the 32-bit PICs would be albe to handle 40MHz directly. To use a smaller PIC you could implement an external prescaler.

    Bob
     
  3. radiotek

    radiotek

    32
    0
    May 31, 2011
    I found a very good website were they are building counters that will measure frequencies uo to 50 Mhz using a PIC 16F628. Maybe I will end up trying this PIC 16F628 if its still available.
    http://www.qsl.net/dl4yhf/freq_counter/freq_counter.html
    Appreciate your help




     
  4. BobK

    BobK

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    Jan 5, 2010
    Hmm. I guess I am wrong then. I looked at several datasheets, but not that one. The others did not indicate a max clock period when using the built in prescaler. This one indicates 10ns of high and 10 ns of low, whcih means it will handle a 50% duty cycle sqauare wave up to 50MHz. If it is not 50% duty cycle it will be out of spec at that frequency.

    Bob
     
  5. Harald Kapp

    Harald Kapp Moderator Moderator

    11,702
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    Nov 17, 2011
    Do you nedd to count the 40 MHz directly?
    Otherwise you could use an external prescaler as Bob suggested. E.g. divide by 10, and count the resulting 4 MHz signal. Easy for many processors. The resulting accuracy will be the same if you count 10 times longer as you would count a 40 MHz signal - provided the signal has a constant frequency.
     
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