frequency meter 8051

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peliasperro

Joined: 19 Jul 2009
Posts: 2

21 Jul 2009 10:46 frequency meter 8051

hello
can any one helpe me about who can i calculate the value of frequency by using counter.

The range of frequency is 0,25Hz to 3000Hz
if i want to input frequency to the microcontro then i want to know what is the value of it .
please i need code to do that and any information about it .

I have calulated, with the timer, the value of the signal pereiod. With this value,
How can i calculate the frequency???
with the formula 1/time????
please i need example to explan that with code in asm.

Crying or Very sad

Thanks

xvibe

Joined: 11 Jul 2003
Posts: 93
Helped: 2
Location: Portugal

21 Jul 2009 16:42 frequency meter

If you have a way for counting the number of pulses in a giving time window then you can measure the frequency.
Example: You need a timer programmed for 1s and a counter connected to INT port of the uC that is incremented each time the interrupt is activated then when the timer reach 1s you just need to do the math 1/counter value and you get the frequency. You need to restart the counter each time the time windows passes the 1s period.

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Prabakaran

Joined: 22 Jan 2007
Posts: 160
Helped: 5
Location: Chennai(India)

14 Aug 2009 13:16 frequency counter 8051 c

Dear ,

I can able to get the Frequency for the same in above method. But what the Problem i m facing is i m getting the value which is nearest to it.

For Example : 23.876 Hz
I am measuring at 24 Hz and 23 Hz which is toggling to these two values.

Please help for the same

nandhu015

Joined: 11 Feb 2006
Posts: 641
Helped: 46
Location: Tamilnadu, India

14 Aug 2009 13:37 frequency meter using c8051

Hai

Quote:

For Example : 23.876 Hz
I am measuring at 24 Hz and 23 Hz which is toggling to these two values.

If you need it in fractions, you have to go for another method.

Measure the time between two pulses and convert it to frequency

frequency = 1/time

Regards
Nandhu