             org 0000h      
             ljmp main  
             org 0003h  
             LJMP l0   
             org 0030h
main:        setb it0 
             setb ea      
             setb ex0     
             mov a,#01h  
loop:        mov p1,a 
             lcall dealy    
             rl a          
             sjmp loop    

l0:          push acc   
             push p1
             mov r1,#07h  
             mov a,#03h   
flash:       mov p1,a
             lcall dealy   
             mov a,p1
             rl a          
             mov p1,#00h  
             lcall dealy    
             djnz r1,flash  
             reti        

dealy:       mov r2,#02 
loop1:       mov r3,#250
loop2:       mov r4,#250
loop3:       nop
             nop
             djnz r4,loop3
             djnz r3,loop2
             djnz r2,loop1
             ret           
             end
