$MOD51
org 0h
clr p3.1
clr p2.1
start:
setb p3.2
clr p2.1
mov r1,#255
mov r3,#255
met1:
call delay
djnz r3,met1
clr p3.2
setb p2.1
mov r1,#255
mov r3,#255
met2:
call delay
djnz r3,met2
sjmp start

delay:
mov r1,#25
del1: mov r2,#25
del2: djnz r2,del2
djnz r1, del1
ret

END