void setup()
{
    volatile long *dir;

    dir = 0x21;   // DDRA
    *dir = 0xFF;                  // segments

    dir = 0x30;   // DDRF
    *dir = 0xFF;                  // digit control
}

void loop()
{
    volatile long *out;
    volatile long i;

    // -------- Digit 1 : 2 --------
    out = 0x31;   // PORTB
    *out = 0xFF;                  // all digits OFF

    out = 0x22;   // PORTA
    *out = 109;                  // 5

    out = 0x31;
    *out = 2;                  // digit-1 ON (ACTIVE-LOW)

    //for(i=0;i<3000;i++);


    // -------- Digit 2 : 5 --------
    out = 0x31;
    *out = 0xFF;                  // all digits OFF

    out = 0x22;
    *out = 91;                  // 2

    out = 0x31;
    *out = 1;                  // digit-2 ON

    //for(i=0;i<3000;i++);
}