PIC - receive data while pulsing pin from low to high and from high to low

[skaarj]

Hello

I am beginner in pic stuff. The pic I am using is the classic 16F877.

Low to high and high to low detection is everything I get when I search the internet. Low to high and high to low triggering at a given frequency is what I wish to achieve. And of course a jump to additional code between these steps.
I'm working at some assembly code which is hard, I am used to do this stuff in old school fashioned way (logic gates). So far I understood bsf and bcf. I need a loop repeating "n" times some nop to achieve the desired delay.

Thank you for your suggestion. I'm searching now for DT interrupts.