How to read frequency signal?

[jsbhalla88]

Hi,
I am working on PIC18F4520.
I have a signal on PIN RB2 whose frequency is 120Hz, pulse width 230 us(approx.) and time between falling edge and next rising edge is about 200 ms.
I have to read this signal and check whether it has the above specifications or not.
how to do this..?????

 

[Hexureus]

Hi,

you need a lab tool like an Oscilloscope.

Now days you can buy very good ones for very little money.
I have my eyes on one of Rigol for quite some time.

 

[Vbase]

Hi,
I am working on PIC18F4520.
I have a signal on PIN RB2 whose frequency is 120Hz, pulse width 230 us(approx.) and time between falling edge and next rising edge is about 200 ms.
I have to read this signal and check whether it has the above specifications or not.
how to do this..?????

The common method is on rising edge to start a counter (timer in counter mode) and to stop the counter on falling edge. The count * period of the clock is the period of your pulse.
You can use PORTB interrupt to start and stop the counter.

 

[jsbhalla88]

Hi,

you need a lab tool like an Oscilloscope.

Now days you can buy very good ones for very little money.
I have my eyes on one of Rigol for quite some time.

I have one.. this is how I checked the pulse characteristics...

 

[jsbhalla88]

EDIT....:
next rising edge is 8 ms, not 200 ms...I mixed it with other signal...