void setup() {
  // put your setup code here, to run once:
  volatile char *dirf=0x30,*outf=0x31,*inf=0x2f,*dira=0x21,*outa=0x22,*dirc=0x27,*outc=0x28;
  *dirf=0x0f;
  *dira=0xff;
  *dirc=0x0f;
volatile char i,n=1;
volatile long l;
while(1)
{
for(i=0;i<4;i++)
{
  *outf=1<<i; 
if((*inf&0xf0)!=0)
  {  for(l=0;l<1000;l++);
    *outc=~n;
    n=(n*2)+1;
    if(n>15)n=1;
    *outa=display((*outf&0x0f),(*inf&0xf0)>>4);
    for(l=0;l<100000;l++);
    while((*inf&0xf0)!=0);
    continue;
  }
  }
  }
}
volatile char display(volatile unsigned char r,volatile unsigned char c)
{
  volatile unsigned char key[4][4]={{0x06,0x5b,0x4f,0x77},
                         {0x66,0x6d,0x7d,0x7c},
                         {0x07,0x7f,0x6f,0x39},
                         {0xff,0x3f,0xff,0x5e}};

                          if(r==4)r=3;
                          if(c==4)c=3;
                          if(r==8)r=4;
                          if(c==8)c=4;
        return key[r-1][c-1];
}


void loop() {
}