Questions regarding measuring of frequency pic 16f887

[daghelgeland]

Hello I have a question regarding using the CCP1 module in Pic16f887.

I use a proximity switch for reading pulses from a rotating wheel. (four pulses pr rotation)

i am interested in detecting frequency in the range of 20-70Hz.


the processor using internal clock

the prescale=1

capturing on falling edge



the program seems to give a ok readings when simulating the proximity sensor with a signal generator. (50%duty).

when i connect the proximity sensor to the circuit the reading get unstable an it seems like pulses are missed.

the frequency from the sensor do not have a duty of 50%, but more like 10%high and 90%low.

is the duty cycle a problem?


Best regards
Dag

[Acetronics2]

when i connect the proximity sensor to the circuit the reading get unstable an it seems like pulses are missed.

WHICH circuit ... ???

FULL scheme compulsory, as we do not have crystal balls on this forum ...

Alain