#include <mc9s12dp512.h>
#define ROWS PORTA
#define COLS PORTB 
void MSDelay(int);
void SerTX(unsigned char);
const unsigned char keypad[4][4] = 
  {
    '1','2','3','A',
    '4','5','6','B',
    '7','8','9','C',
    '*','0','#','D'
  };
unsigned char column,row;
void main(void) {
  SCI0BDH=0x0;		
  SCI0BDL=0x0D;	
  SCI0CR1=0x0;		
  SCI0CR2=0x0C;
  DDRA =0xFF; 		
  DDRT =0xFF; 		
  DDRB =0;  		
  while(1)
  {
    do
    {
      ROWS = 0; 	
      column = COLS; 	
      column = column & 0x0F; 	
    }while(column != 0x0F);
    do
    {
      do
      {
        MSDelay(15); 		
        column = COLS; 		
        column = column & 0x0F; 
      }while(column == 0x0F);
      MSDelay(15); 			
      column = COLS; 		
      column = column & 0x0F;
    }while(column == 0x0F);	
    while(1)
    {
      ROWS = 0xFE; 		
      column = COLS;	 	
      column = column & 0x0F;
      if(column != 0x0F)		
      {
        row = 0;
        break;
      }
      ROWS = 0xFD; 		
      column = COLS; 		
      column = column & 0x0F;
      if(column != 0x0F)		
      {
        row = 1;
        break;
      }
      ROWS = 0xFB; 		
      column = COLS; 		
      column = column & 0x0F;
      if(column != 0x0F)		
      {
        row = 2;
        break;
      }
      ROWS = 0xF7; 		
      column = COLS; 		
      column = column & 0x0F;
      if(column != 0x0F)		
      {
        row = 3;
        break;
      }
      column = 0; 			
      break;
    }
    if(column == 0x0E)  		
    {    
      PTT = keypad[row][0];  
      SerTX(keypad[row][0]);	
    }
    else if(column == 0x0D)	
    {    
      PTT = keypad[row][1];  
      SerTX(keypad[row][1]);	
    }
    else if(column == 0x0B)	
    {    
      PTT = keypad[row][2];  
      SerTX(keypad[row][2]);	
    }
    else if(column == 0x07)	
    {    
      PTT = keypad[row][3];  
      SerTX(keypad[row][3]);	
    }
  }
}
void SerTX(unsigned char x)
{
  while(!(SCI0SR1 & SCI0SR1_TDRE_MASK)); 
  SCI0DRL=x;				
}  
void MSDelay(int ms)
{
  int i,j;
  for(i=0;i < ms; i++)
    for(j=0;j < 329; j++);
}