//keypad standing algorithm
void setup() {
  // put your setup code here, to run once:
volatile char *dirf,*dirk,*dira,*dirc,x,i,j;
volatile char *outc,*outf,*ink,*outa;
dirc=0x27,dirf==0x30;dirk=0x107;dira=0x21;
outc=0x28,outf=0x31;ink=0x106;outa=0x22;
*dirf=0x0F;*dirk=0x00;*dira=0x0F;
*outa=0x05;
while(1)
{
  for(i=0;i<4;i++)
  {
    *outf=1<<i;
    *outa=*ink;
    //red:column
    //blue:row
    if(*ink!=0)
    {
       *outc=1<<i;
    //for(j=0;j<100000;j++);
       *outc=0; 
    }
  }
}
}

void loop() {
  // put your main code here, to run repeatedly:

}