//*********************************************************
//Title:    Keypad input to PORTB LED 
//          Based on Example 12.4C                        *
//          HCS12 Microcontroller And Embedded Systems    *
//          Using Assembly and C with CodeWarrior         *
//          1st Edition                                   *
//          by Mazidi & Causey          
//Modified and tested by Travis Chandler                               
//Platform: Wytec Dragon12 plus Dev board                 *
//Compiler: Feescale CodeWarrior IDE v5.9.0               *

//*********************************************************
//On Dragon12+ board, the rows and columns of 4x4 keypad are connected to PORTA. 
//See page 26 of Dragon12+ User's Manual
//As you press any key the ASCII value for the key is placed on the LEDs of PORTB

#include <hidef.h>      /* common defines and macros */
#include "derivative.h"      /* derivative-specific definitions */

void mSDelay(unsigned int);

const unsigned char keypad[4][4] =
{
'1','2','3','A',
'4','5','6','B',
'7','8','9','C',
'*','0','#','D'
};
unsigned char column,row;

/**************MAIN*******************************/
void main(void){                          //OPEN MAIN
   DDRB = 0xFF;                           //MAKE PORTB OUTPUT
   DDRJ |=0x02; 
   PTJ &=~0x02;                            //ACTIVATE LED ARRAY ON PORT B
   DDRP |=0x0F;                           //
   PTP |=0x0F;                            //TURN OFF 7SEG LED
   DDRA = 0x0F;                           //MAKE ROWS INPUT AND COLUMNS OUTPUT
   
 
   while(1){                              //OPEN WHILE(1)
      do{                                 //OPEN do1
         PORTA = PORTA | 0x0F;            //COLUMNS SET HIGH
         row = PORTA & 0xF0;              //READ ROWS
      }while(row == 0x00);                //WAIT UNTIL KEY PRESSED //CLOSE do1



      do{                                 //OPEN do2
         do{                              //OPEN do3
            mSDelay(1);                   //WAIT
            row = PORTA & 0xF0;           //READ ROWS
         }while(row == 0x00);             //CHECK FOR KEY PRESS //CLOSE do3
         
         mSDelay(15);                     //WAIT FOR DEBOUNCE
         row = PORTA & 0xF0;
      }while(row == 0x00);                //FALSE KEY PRESS //CLOSE do2

      while(1){                           //OPEN while(1)
         PORTA &= 0xF0;                   //CLEAR COLUMN
         PORTA |= 0x01;                   //COLUMN 0 SET HIGH
         row = PORTA & 0xF0;              //READ ROWS
         if(row != 0x00){                 //KEY IS IN COLUMN 0
            column = 0;
            break;                        //BREAK OUT OF while(1)
         }
         PORTA &= 0xF0;                   //CLEAR COLUMN
         PORTA |= 0x02;                   //COLUMN 1 SET HIGH
         row = PORTA & 0xF0;              //READ ROWS
         if(row != 0x00){                 //KEY IS IN COLUMN 1
            column = 1;
            break;                        //BREAK OUT OF while(1)
         }

         PORTA &= 0xF0;                   //CLEAR COLUMN
         PORTA |= 0x04;                   //COLUMN 2 SET HIGH
         row = PORTA & 0xF0;              //READ ROWS
         if(row != 0x00){                 //KEY IS IN COLUMN 2
            column = 2;
            break;                        //BREAK OUT OF while(1)
         }
         PORTA &= 0xF0;                   //CLEAR COLUMN
         PORTA |= 0x08;                   //COLUMN 3 SET HIGH
         row = PORTA & 0xF0;              //READ ROWS
         if(row != 0x00){                 //KEY IS IN COLUMN 3
            column = 3;
            break;                        //BREAK OUT OF while(1)
         }
         row = 0;                         //KEY NOT FOUND
      break;                              //step out of while(1) loop to not get stuck
      }                                   //end while(1)

      if(row == 0x10){
         PORTB=keypad[0][column];         //OUTPUT TO PORTB LED
 
      }
      else if(row == 0x20){
         PORTB=keypad[1][column];
 
      }
      else if(row == 0x40){
         PORTB=keypad[2][column];
 
      }
      else if(row == 0x80){
         PORTB=keypad[3][column];
 
      }

      do{
         mSDelay(15);
         PORTA = PORTA | 0x0F;            //COLUMNS SET HIGH
         row = PORTA & 0xF0;              //READ ROWS
      }while(row != 0x00);                //MAKE SURE BUTTON IS NOT STILL HELD
   }                                      //CLOSE WHILE(1)
}                                         //CLOSE MAIN



/**********************SUBROUTINES***********/

void mSDelay(unsigned int itime){
unsigned int i; unsigned int j;
   for(i=0;i<itime;i++)
      for(j=0;j<4000;j++);
}