ORG 0000H
        JMP MAIN0
      
        ORG     2030H
MAIN0:  NOP
        NOP
        NOP
        CLR A
        MOV DPTR,#1F20H
        LCALL Program_One_Byte;
        AJMP $

Program_One_Byte:
                   ORL   SFCF,#40H    
                   MOV   SFAH,DPH     
                   MOV   SFAL,DPL     
                   MOV   SFDT,A       
                   MOV   B,A          
                   MOV   SFCM,#0EH    
                   ACALL WAIT         
                   ORL   SFCF,#40H    
                   MOV   SFAH,DPH     
                   MOV   SFAL,DPL     
                   MOV   SFCM,#0CH    
                   MOV   A,SFDT       
                   XRL   A,B          
                   RET 
WAIT:              MOV   A,SFST       
                   JB    ACC.2,WAIT   
                   RET 
    SFCF DATA 0B1H
SFCM DATA 0B2H 
SFAL DATA 0B3H
SFAH DATA 0B4H
SFDT DATA 0B5H
SFST DATA 0B6H
    AUXR DATA 08EH
    end