void setup() 
 {
  // put your setup code here, to run once:
volatile long i,j;
volatile char *dirc,*dirf,*dirk,*dira,x;
volatile char *outc,*outf,*ink,*outa;
dirc=0x27;  dirf=0x30;  dirk=0x107; dira=0x21;
outc=0x28;  outf=0x31;  ink=0x106;  outa=0x22;
*dirf=0x01; *dirk=0x00;  dira=0x0F;
while(1) 
{
  for(i=0;i<4;i++)
  {
    *outf=1<<i; 
    *outa=*ink;
    if(*ink!=0)
    {
      *outc=1<<i;
    for(j=0;j<200000;j++);
    *outc=0;
    }
  } 
}
 }
void loop()
{

}