RB0 Input pin configuration

Hi there!

My RB0 interrupt pin I configured as an input pin it’s an active low type.

It’s working well.

When I’m giving pulse from a 555 circuit to the RB0 do I have to configure it to rising edge or falling edge on the OPTION REG, INTEDG?

By default this bit has clear.

Thanks.

You haven't supplied enough information.
If you're just trying to detect frequency it doesn't matter. If you're trying to detect duty cycle it's more complicated than just picking rising or falling edge.