OK, I tried with this approach and it works, but as you will see in the code, even though the object is under 5 meters away (for eg. 4meters), PORTC.2 goes high & does not toggle. Is there something wrong with my calculation. It is working fine upto 1 meter. LED connected to PortC.2 does alterate it's toggling speed depending upon how far is the object under 1 meter. My latest code goes like this:
Code:
; Phase2: RA0=TRIG (OUTPUT) ;;;;RA1- PWM (INPUT)
w1 var word

pause 500
main1:
w1=0
High PortA.0
pause 1
Low PortA.0
pause 1
High PortA.0

main:
Pulsin PortA.1,0,w1
if w1>500 or w1=0 then 
		high PortC.2
	else
		toggle PortC.2
			pause w1
	endif
goto main1
end