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.

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:

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:


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

    led video screen

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

    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.

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

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

      Just for reference:

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