up down counter with External EEprom interface using 16F877A

sbit digit1 at PORTB.B0;
sbit digit2 at PORTB.B1;
sbit digit3 at PORTB.B2;
sbit digit4 at PORTB.B3;
//===========================================
sbit DATA_pin at  PORTC.B1;
sbit LATCH_pin at PORTC.B2;
sbit CLCOK_pin at PORTC.B0;
//===========================================


//int   count = 0;
unsigned pstatus = 0;
unsigned char binary_pattern[]={0xC0,0xF9,0xA4,0xB0,0x99,0x92,0x82,0xF8,0x80,0x90};
unsigned int counter; //=0;
unsigned int a1,a2,a3,a4; // temporary variables to store data of adc
void clock_signal(void){
   CLCOK_pin = 1;
    delay_us(500);
   CLCOK_pin = 0;
    delay_us(500);
}
void latch_enable(void)
   {
    LATCH_pin = 1;
    delay_us(500);
    LATCH_pin = 0;
    }
void send_data(unsigned int data_out)
{
    int i;
    unsigned hold;
    for (i=0 ; i<8 ; i++)
    {
        DATA_pin = (data_out >> i) & (0x01);
        clock_signal();
    }
    latch_enable(); // Data finally submitted
}


void main()
{
  TRISC.B0 = 0; // Set  DATA_pin as output pin
  TRISC.B1 = 0; // Set  CLCOK_pin as output pin
  TRISC.B2 = 0; // Set LATCH_pin as output pin

  TRISC.F4= 1;   //SDA
  TRISC.F3= 1;  //SCL

   //**********************************************

   //**********************************************

  //===========================================
  TRISD = 0x30;                      // Configure RB3 & RB4 pins as inputs
  // pstatus = 1;
  TRISB=0x00;
  PORTB = 0X00;


  digit1 = 0;
  digit2 = 0;
  digit3 = 0;
  digit4 = 0;
  while(1)
      {


         a1 = counter / 1000;   // holds 1000's digit
         a2 = ((counter/100)%10); // holds 100's digit
         a3 = ((counter/10)%10);  // holds 10th digit
         a4 = (counter%10);  // holds unit digit value
        //  counter = I2C1_Rd(0); // Read the data (NO acknowledge)

         send_data(binary_pattern[a1]); // send 1000's place data to fourth digit
        digit1=1;   //  turn on forth display unit
        delay_ms(3);
        digit1=0;   //  turn off forth display unit
      
        send_data(binary_pattern[a2]);  // send 100's place data to 3rd digit
        digit2=1;    //  turn on 3rd display unit
        delay_ms(3);
        digit2=0;  //  turn off 3rd display unit
      
        send_data(binary_pattern[a3]);  // send 10th place data to 2nd digit
        digit3 = 1;  //  turn on 2nd display unit
        delay_ms(3);
        digit3 = 0;   //  turn off 2nd display unit
     
       send_data(binary_pattern[a4]);  // send unit place data to 1st digit
       digit4 = 1;  //  turn on 1st display unit
       delay_ms(3);
       digit4 = 0;  //  turn off 1st display unit

      
     //================================================
         if(PORTD.F4 ==0)
         {
         counter++;
         if(counter>9999)
         //counter =0;
         delay_ms(200);
            I2C1_Init(100000); // initialize I2C communication
            I2C1_Start(); // issue I2C start signal
            I2C1_Wr(0xA0); // send byte via I2C (device address + W)
            I2C1_Wr(0); // send byte (address of EEPROM location)
            I2C1_Wr(1); // send byte (address of EEPROM location)
            I2C1_Wr(counter); // send data (data to be written)
            I2C1_Stop(); // issue I2C stop signal
         }
       
         if(PORTD.F5 ==0)
         {
         counter--;
         if(counter>9999)
         //counter =0;
         delay_ms(200);
       
            I2C1_Init(100000); // initialize I2C communication
            I2C1_Start(); // issue I2C start signal
            I2C1_Wr(0xA0); // send byte via I2C (device address + W)
            I2C1_Wr(0); // send byte (address of EEPROM location)
            I2C1_Wr(1); // send byte (address of EEPROM location)
            I2C1_Wr(counter); // send data (data to be written)
            I2C1_Stop(); // issue I2C stop signal

         }


      }

           I2C1_Start(); // issue I2C start signal
           I2C1_Wr(0xA0); // send byte via I2C (device address + W)
           I2C1_Wr(0); // send byte (data address)
           I2C1_Wr(1); // send byte (address of EEPROM location)
           I2C1_Repeated_Start(); // issue I2C signal repeated start
           I2C1_Wr(0xA1); // send byte (device address + R)
           counter = I2C1_Rd(0); // Read the data (NO acknowledge)
           I2C1_Stop(); // issue I2C stop signal
}