用138译码器控制位选和锁存器控制段选的数码管如何消隐？？

共阴接法的话：void display()

{   
    P2=0XFF;
    P0=0XFF;
    P0 = sma_t[i%10] ;
    P2 = sba_t[7] ;
    delay(2) ;
     P2=0XFF;
     P0=0XFF;

    P0 = sma_t[i/10] ;
    P2 = sba_t[6] ;
    delay(2) ;
 P2=0XFF;
 P0=0XFF;
    P0 = 0x40 ;
    P2 = sba_t[5] ;
    delay(2) ;
P2=0XFF;
 P0=0XFF;
    P0 = sma_t[j%10] ;
    P2 = sba_t[4] ;
    delay(2) ;
P2=0XFF;
 P0=0XFF;
    P0 = sma_t[j/10] ;
    P2 = sba_t[3] ;
    delay(2) ;
P2=0XFF;
 P0=0XFF;
    P0 = 0x40 ;
    P2 = sba_t[2] ;
    delay(2) ;
P2=0XFF;
 P0=0XFF;
    P0 = sma_t[k%10] ;
    P2 = sba_t[1] ;
    delay(2) ;
P2=0XFF;
 P0=0XFF;

}   


共阳的话就把全部
    P0 = sma_t[x] ;
    P2 = sba_t[x] ;  
全部调换为
P2 = sba_t[x] ;  
P0 = sma_t[x] ;
P0=0XFF;
P2=0XFF;