a higher resolution frequency counter

I found this project in a really old magazine from GDR times, which explained the reciprocal counter. This type of counter has the advantage that the +1 error stays constant even with low frequencies. When I started working with CPLDs, I used it as my first learning project. But since it needs a MCU to work, I decided later on to port it to the PSoC5 kit I have laying around. This allows me to have the whole counter in a single chip - and in addition the whole system gets much simpler to develop and program.


  • 24 bit resolution, doesn't depend on input frequency
  • up to 12MHz input frequency (the PSoC5 counter isn't faster than that)
  • about 0.7 measurements per second (depends on the reference clock and the resolution)