To count external pulses fed to input pin of FPGA for timimng window of 1 second

[akshay.patil630]

Respected Sir,

Sir, I am using FPGA kit xc3s500e. I have connected output of voltage to frequency converter to input pin of FPGA and a I want to measure number pulses fed to input of fpga (with ton=20microsecond fixed but toff varies), for timimg window of 1 second.

Please, help me in vhdl code how can i design timer of 1sec to count external pulses fed to FPGA input pin?


Regards,

Akshay

 

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If you have a clock oscillator input to the FPGA it toggles at some frequency (e.g. 50 MHz). Now how many times does this clock toggle in a second? Answer that and you should know how to count out 1 second of time.