help me Please

it code don't work

it's wrong

-----------------------------------------------------------
INCLUDE "modedefs.bas"
define osc 4
w var word
r var word
a var word
tr var PORTA.0 'Trig pin
ec var PORTA.1 ' Echo pin
TRISA = %00000010
TRISB = %00000000
PORTB = %00000000
w = 0
Main :
low tr
high tr
pauseus 10
low tr
pulsin ec,1,w
r = w/58
if r < 10 then
PORTB = %11111111
pause 200
endif
goto main
end
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Sorry I bad eng

data sheet HC-SR04
https://www.google.co.th/url?sa=t&rc...55325884,d.bmk