Wednesday, September 23, 2015

100MHz frequency counter with LCD display


Update November 26, 2015:
I made a full project with preamp/signal conditioning and power supply with soft on/of switch. It is published here.


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This is the same as the previous frequency counter but the output is on the 16x2 LCD display.
For more details about how it work look here: http://diyfan.blogspot.bg/2015/08/100mhz-frequency-counter.html




Bellow are pictures and short video, showing the frequency counter in action. As my oscilloscope is with only 70Mhz bandwidth, the 110+ MHz signal looks like sinusoidal, but it is probably not.
I generate the test signal with SN74HC00N connected in this way:






Source code and HEX file can be downloaded here: http://bit.ly/FreqC-LCD




10 comments:

  1. Excellent post and wonderful blog, I really like this type of interesting articles keep it you.

    led video screen

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  2. Good afternoon I would like you please tell me what value is the coil L1 FB SMD1206 thanks

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    1. This is simple ferrite bead for limiting the interference between two parts of the circuit. If I recall correctly it was 120Ohm at 100MHz. I am not sure how critical it is as there is also decoupling capacitor near both IC's supply pins, so it should work fine with piece of wire instead the ferrite bead.

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  3. Is it possible for you to share your Eagle component library MyLib1.lbr over here?

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    1. Sorry, my bad - I did not know how to export libraries in Eagle. Now I actually know :)

      Just for reference:
      https://forum.sparkfun.com/viewtopic.php?t=13875

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  4. This comment has been removed by the author.

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  5. This comment has been removed by the author.

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    1. Dear Hristo!

      I try to replicate this frequency counter, but I have problems with the lcd module. Almost never software can initialize the LCD, it works only when I pass my finger at the outputs 1, 2 and 3 of the chip PIC16F628A. I mean this is timing issue in LCD routines, but I don't have C compiler. Can you replace this routines with better one and compile that? Please... I was try 3 different LCDs with same results.

      Best Regards!

      Tihomir Benko

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  6. Привет, Кристо, я не понимаю, как ты смог достичь такой высокой частоты измерения. Даташит PIC628A показывает, что ширина импульса любой полярности не должна быть меньше 10 наносекунд. Поскольку меандр имеет два импульса по 10 нс, максимальная частота не может быть более 50 МГц. Допустим, скоростные данные на 10-20% лучше, но 100 МГц потребует вдвое больше бистродействия.
    Тестовая схема, которую ты показываеш, генерирует в целом меандр с частотой около 25 МГц, и я никогда не слышал о микросхемах серии 74C, работающих на 100 и более МГц.

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