stepper motor programming (assembly language)

org 0
mov a,#66h
back:
mov p0,a
rr a
acall delay
sjmp back
delay:
mov r2,#100
h1:
mov r3,#255
h2:
djnz r3,h2
djnz r2,#h1
ret
end


Having problem with the program?? plz click on the following
undrstanding-stepper-motor-programming.