Applications of Embe ...

 #include <main.h> // the file main.h with the

                  // initial settings is included.

                  // This file must be placed in the same

                  // folder with the project.

                  // Also the 18F4550.h file must exist

                  // in the same folder with the project

#include <keypad.h>   // The h file of the keypad driver

                      // should be in the same folder where we will save our program.

                      // The #define row0 PIN_B4 etc statements in keypad.h

                      // should be checked and possibly modified.

                      // These statements determine the pins of the microcontroller

                      // that are connected to the keypad 4x4.

#byte PORTB =0xF81  

                     // We attribute to the memory position 0xF81 the name PORTB.

                     // This means that we define a 8 bit variable whose value

                     // will be stored to the memory position F81h.

                     // The memory position F81h is the PORTD data register.

#byte PORTD=0xF83    // F83h is the position or PORTD data register

                     // at the data memory of the microcontroller

                     // SFR Special Function Register

//initialization routine

void init(void);

// ********* main program ************************

void main(){

   char k;      //variable for storing the ASCII code of the key pressed

   init();      //initialization routine

   kbd_init();  //initialization routine for the keypad 4x4

   while(TRUE){

      k=kbd_getc(); //Keypad reading.

                    //If a key is pressed, the variable k gets the ASCII code of the key.

                    //If no key is pressed, the function kbd_getc() returns the value 0.

      If(k!=0){     //If a key is pressed

         PORTD=k;   //The ASCII code of the key pressed is transferred to PORTD

      }        

   }

}

//initialization routine

void init (void){

   set_tris_d(0x00);   //PORTD is defined as output

   PORTD=0x00;         //PORTD takes the initial value of 0x00