Measuring pulse shorter than 1 microsecond

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Joined: 09/06/2017
Location: Finland
Posts: 319
Posted: 06:48pm 21 Nov 2022      

Thanks Volhout for the nice PIO-program!  
I have tested the program as a frequency counter for an inductance meter. The PicoMite with your program seems to work well about up to 5MHz input signal, which seems to be more than enough for this excercise.

I have no experience at all about PIO-programming, but I have a few questions.
1. cnt%(). Seems to hold 5 very similar (not always equal) values, of which only cnt%(4) is used. Are these the results of 5 different measurements?
2. I am running PicoMite at 378MHz and changed your program to also use 378MHz for the PIO (f=378e6). What would you expect the maximum measurable frequency to be? (I am using Geoff's signalgenerator and I think that the amplitude becomes too low at higher frequencies. I believe this is the reason for not acheiving higher measurements than 5MHz. Unfortunately I have no proper signal generator for higher frequency).