CCP capture

[in_nursery]

Hi all
I use the capture mode for reading a signal frequency.
I use capture on rising edge.
But my signal is not very clean, I have rebound at the falling edge.

This is how my signal looks like.

___|¨¨¨¨¨¨¨¨¨¨¨¨¨¨|_|¨|_|¨|_|¨|________________________|¨¨¨¨

Is there a software way to ignore this rebound ?

Thanks in advance

[Ttelmah]

It can be done to some extent. For instance, you could add code to reject any period shorter than a particular count. However it is going to use quite a bit of processor time, and restrict the range of frequencies that can be supported. A hardware solution is likely to be much better.
In the ISR, calculate the 'delta' from the last edge, and if it is less than a figure corresponding to your maximum frequency, exit immediately, and don't update the 'old', and don't flag the new value as ready.

[in_nursery]

Ttelmah

[Ttelmah]

The proper way to do it in hardware is to start by looking at the actual signal processing (hysteresis), and possibly add a PLL.

Problem with the software is 'which edge to actually use'...