#include "at91sam3x8.h"
#include <stdlib.h>
#include "system_sam3x.h"

#define PIOC_PER (unsigned int *)(0x400E1200)
#define PIOC_ODR (unsigned int *)(0x400E1214)
#define PIOC_PDSR (unsigned int *)(0x400E123C)
#define PIOC_OER (unsigned int *)(0x400E1210)
#define PIOC_PDR (unsigned int *)(0x400E1204)
#define PMC_PCER0 (unsigned int *)(0x400E0610)
#define PMC_PCER1 (unsigned int *)(0x400E0700)
#define PIOD_CODR (unsigned int *)(0x400E1434)
#define PIOD_SODR (unsigned int *)(0x400E1430)
#define PIOC_CODR (unsigned int *)(0x400E1234)
#define PIOC_SODR (unsigned int *)(0x400E1230)
#define PIOC_PUDR (unsigned int *)(0x400E1260)
#define PIOD_PUDR (unsigned int *)(0x400E1460)

void pins_int();
int counter=0;

unsigned int rows[4];
unsigned int columns[3];
int value=0;


 int col=0;// increase variabel för kolumnerna
  int row=0; // increase variabel för raderna

  void pins_int(){

 *PIOD_PER = 0xE;
 //*PMC_PCER1= (1<<13);// Ställer in Peripheral clock.
 *PIOC_PER= 0x3BC;// Enablar alla pins som raderna och kolumnerna.
 *PIOC_ODR= 0x3BC;//Disablar alla pins för raderna till output.
 *PIOC_OER= 0x380;

 *PIOD_CODR= 0x4;
 *PIOC_PUDR=0x380;
 *PIOD_PUDR=0xC;

  }

int func(void){

    columns[0]=0x80;
    columns[1]=0x100;
    columns[2]=0x200;

    rows[0] = 0x4;
    rows[1] = 0x8;
    rows[2] = 0x10;
    rows[3] = 0x20;


  for(col=0;col<3 && value==0 ;col++){
      *PIOC_CODR=columns[col];
      for(row=0; row<4 && value==0;row++){
        if((*PIOC_PDSR & rows[row-1])==0){
        value=3*row+col+1;
        }
  *PIOC_SODR=columns[col];
      }
    }
  return(value);
}

  /*Value = 0=Check
Clear OE KEY BUS (Active Low)= Check
Make all Column pin as output= Check
Set all Column pin as high= Check
Loop Column=Check
Clear one column at the time=Check
Loop Row=Check
Read row and check if bit is zero=Check
Value = Row*3+Col+1;=Check
end loop Row=Check
Set the column again=Check
End loop Column=Check
Make all Column pin as input=Check
Return Value. =Check.*/



int main()
{
   pins_int();
  SystemInit();
   SysTick_Config(84000);
  while(1){
  func();

  }
}

void Systick_Handler(){
counter++;
}