How to add a new 7 seg display with unique pattern changeable by interrupt?

[Narendra1190]

hii frds..
need your help.working on 89s52 project.there are already SIX 7-seg dislplay. i want to add one more 7-segment display controlled by an interrupt.when i m doing it is affecting switching of other six display..how can i do multiplexing with two differnt pattern such that one numerical pattern for six 7-seg. and the other symbolic pattern for seventh seg. display controlling with interrupt.
how shld i add code?

the working code of six 7 seg. display is below.

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Code C - [expand]
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void seven_seg_disp (void) interrupt 1  //timer 0 isr
{
    EA = 0;
    TR0 = 0;
    if(i == 1)
    {
        P0_1 = 1;P0_2 = 1;P0_3 = 1;
        P0_4 = 1;P0_5 = 1;//P0 = 0xFE;  //1add   //1111 1110
        P2 = lcddata[Li[0]];    //0
        P0_0 = 0;
        i++;
    }
    else if(i == 2)
    {
        P0_0 = 1;P0_2 = 1;P0_3 = 1;
        P0_4 = 1;P0_5 = 1;//P0 = 0xFD; //2add    //1111 1101
        P2 = lcddata[Li[1]];    //1
        P0_1 = 0;
        i++;
    }
    else if(i == 3)
    {
        P0_0 = 1;P0_1 = 1;P0_3 = 1;
        P0_4 = 1;P0_5 = 1;//P0 = 0xFB; //3add   //1111 1011
        P2 = lcddata[Li[2]]; //2
        P0_2 = 0;
        i++;
    }
    else if(i == 4)
    {
        P0_0 = 1;P0_1 = 1;P0_2 = 1;
        P0_4 = 1;P0_5 = 1;//P0 = 0xF7; //4add    //1111 0111
        P2 = lcddata[Li[3]]; //3
        P0_3 = 0;
        i++;
    }
    else if(i == 5)
    {
        P0_0 = 1;P0_1 = 1;P0_2 = 1;P0_3 = 1;
        P0_5 = 1;//P0 = 0xEF; //5add    //1110 1111
        P2 = lcddata[Li[4]]; //4
        P0_4 = 0;
        i++;
    }
    else if(i == 6)
    {
        P0_0 = 1;P0_1 = 1;P0_2 = 1;P0_3 = 1;
        P0_4 = 1;//P0 = 0xDF; //6add  // 1101 1111
        P2 = lcddata[Li[5]]; //5
        P0_5 = 0;
        i = 1;
    }
    }
    TH0 = 0xFC;
    TL0 = 0xEC;//   TL0 = 0xBE;
    TR0 = 1;
    EA = 1;
}
 
void appetizers (void)
{
     P1 = 0x00;      //to disable stapper motor
     P0 = 0xFF;
     TMOD = 0x11;    //timer 0 and timer 1 both used
     EA = 1;
     ET0 = 1;
     EX0 = 1;        //enables external int0
     IT0 = 1;        //ex interrupt0 in falling edge mode
     TH0 = 0xFC;     
     TL0 = 0xEC;//TL0 = 0xBE;
     TR0 = 1;        //timer0 is used for refreshing 7seg array.
}

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