how to write a mikroc code for ultrasonic sensor hc-sr04

hi :)
I want to write a mikroc code for ultrasonic sensor hc-sr04 and I need help :eek:
I am using pic16f876a

I am using ultrasonic sensor above my robot ... I want to make my robot go forward when the echo pin got signal and if the distance between my robot and the other one 50 cm or less

couls you plz help me ??