// #include <Arduino.h>

// // put function declarations here:
// #define TWINT 7
// #define TWSTA 5
// #define TWSTO 4
// #define TWEN 2


// void TWI_init(void);
// void start_TWI(void);
// void stop_TWI(void);
// void wait_Flag();
// void check_ACK(uint8_t ACK);
// void TWI_write(uint8_t SLA_W);


// #define TWCR (*(volatile uint8_t*)0xBC)
// #define TWDR (*(volatile uint8_t*)0xBB)
// #define TWSR (*(volatile uint8_t*)0xB9)
// #define TWBR (*(volatile uint8_t*)0xB8)

// uint8_t decToBCD(uint8_t val) {
//   return ((val / 10) << 4) | (val % 10);
// }

// uint8_t bcdToDec(uint8_t val) {
//   return ((val >> 4) * 10) + (val & 0x0F);
// }


// uint8_t raw;
// void setup() {
//   // put your setup code here, to run once:
//   Serial.begin(9600);
//   TWI_init();
//   start_TWI();     //starting
//   check_ACK(0x10);

//   TWI_write(0xD0);    //slave address with write bit
//   check_ACK(0x18);

//     TWI_write(0x00);//seconds register address in rtc   
//     check_ACK(0x28);

//     TWI_write(decToBCD(50));  // Sends 0x50  seconds to RTC   
//     check_ACK(0x28);

//     TWI_write(decToBCD(45));  // minutes   
//     check_ACK(0x28);

//     TWI_write(decToBCD(9));  // hours  
//     check_ACK(0x28);

//     TWI_write(decToBCD(03) );  //day
//     check_ACK(0x28);

//     TWI_write(decToBCD(18) );  // date
//     check_ACK(0x28);
//     TWI_write(decToBCD(4));  // month
//     check_ACK(0x28);
//     TWI_write(decToBCD(25) );  // year   
//     check_ACK(0x28);

//   stop_TWI();
  

//   // //   //reading

  
// }

// void TWI_init(void) {
//   TWCR = 0x00;             // Reset control register
//   TWSR = 0x00;          // Prescaler = 1
//   TWBR = 72;            // Set bit rate
//     // Enable TWI
//     delay(500);
// }


// void start_TWI(void) {       //used for both start and repeated start

//   TWCR = (1 << TWINT) | (1 << TWSTA) | (1 << TWEN); //When I write 1 to TWINT, hardware clears it to 0 to begin the operation, and once the operation is done, hardware sets it to 1 again.
//   wait_Flag();

//   // check_ACK(0x10);
  
// }
// void stop_TWI(void) {
//   TWCR = (1 << TWINT) | (1 << TWEN) | (1 << TWSTO);
//   wait_Flag();
// }
// void wait_Flag() {              //waiting for hardware to set TWINT(1)
//   while (!(TWCR & (1 << TWINT)));
// }
// void check_ACK(uint8_t expected_ACK) {
//   uint8_t status = TWSR & 0xF8;
//   if (status != expected_ACK) {
//     Serial.print("Expected ACK: 0x");
//     Serial.print(expected_ACK, HEX);
//     Serial.print(" but got: 0x");
//     Serial.println(status, HEX);
//   }
// }

// void TWI_write(uint8_t SLA_W) {
//   TWDR = SLA_W;                             // Load data/address into TWDR
//   TWCR = (1 << TWINT) | (1 << TWEN);        // Start transmission                              // Wait for TWINT = 
//    wait_Flag();
// }


// void loop() {
//   start_TWI();
//   TWI_write(0xD0);     // Slave address with write bit
//   check_ACK(0x18);

//   TWI_write(0x00);     // Start from seconds register
//   check_ACK(0x28);

//   start_TWI();         // Repeated start
//   TWI_write(0xD1);     // Slave address with read bit
//   check_ACK(0x40);

//   // Read Seconds
//   TWCR = (1 << TWINT) | (1 << TWEN) | (1 << TWEA);
//   wait_Flag();
//   uint8_t seconds = bcdToDec(TWDR & 0x7F);

//   // Read Minutes
//   TWCR = (1 << TWINT) | (1 << TWEN) | (1 << TWEA);
//   wait_Flag();
//   uint8_t minutes = bcdToDec(TWDR);

//   // Read Hours
//   TWCR = (1 << TWINT) | (1 << TWEN) | (1 << TWEA);
//   wait_Flag();
//   uint8_t hours = bcdToDec(TWDR);

//   // Read Day
//   TWCR = (1 << TWINT) | (1 << TWEN) | (1 << TWEA);
//   wait_Flag();
//   uint8_t day = bcdToDec(TWDR);

//   // Read Date
//   TWCR = (1 << TWINT) | (1 << TWEN) | (1 << TWEA);
//   wait_Flag();
//   uint8_t date = bcdToDec(TWDR);

//   // Read Month
//   TWCR = (1 << TWINT) | (1 << TWEN) | (1 << TWEA);
//   wait_Flag();
//   uint8_t month = bcdToDec(TWDR);

//   // Read Year (last byte, so send NACK)
//   TWCR = (1 << TWINT) | (1 << TWEN); // NACK
//   wait_Flag();
//   uint8_t year = bcdToDec(TWDR);

//   stop_TWI();

//   // Print output
//   Serial.print("Time: ");
//   Serial.print(hours);
//   Serial.print(":");
//   Serial.print(minutes);
//   Serial.print(":");
//   Serial.println(seconds);

//   Serial.print("Date: ");
//   Serial.print(date);
//   Serial.print("-");
//   Serial.print(month);
//   Serial.print("-20");
//   Serial.println(year);

//   Serial.print("Day Number: ");
//   Serial.println(day);

//   delay(1000);
// }
void init_port(void);
void outdata(char);
void outcontrol(char);
void init_lcd(void);
void lcd_control_write(void);
void write_data(char);
void write_string(char*);
void set_cursor_second_row(void);  
void set_cursor_first_row(void);  
void setup() {
  // put your setup code here, to run once:
  init_port();
  init_lcd();
  set_cursor_first_row();
  write_string("Thanks bhaiya for your guidance");
}
void write_string(char *ptr) {
  volatile long count=0;
  while (*ptr != 0) {    
    // if(count==16){
    //   set_cursor_second_row();
    //    lcd_control_write();      
    // }
    write_data(*ptr);                // Write character to the LCD
    ptr++;
    count++;
                      
  }
}


void init_port(void){
  volatile uint8_t *portF_dir=(volatile uint8_t*)0x30;
  volatile  uint8_t *portK_dir=(volatile uint8_t*)0x107;
  *portF_dir=0x03;
  *portK_dir=0xFF;
}
void outdata(char out_data){
  volatile uint8_t *portK_data;
  portK_data= (volatile uint8_t*)0x108;
  *portK_data=out_data; 
}
void outcontrol(char out_data){
   volatile uint8_t *portK_data;
   portK_data=(volatile uint8_t*)0x31;
  *portK_data=out_data;
}
void init_lcd(void){ 
  outdata(0x38);  //function set: 8bit ,2line , 5*8
  lcd_control_write();  //giving pulse to enable
  outdata(0x0F);   //display on ,cursor blinking
   lcd_control_write();  
  outdata(0x01);  //clear display
  lcd_control_write();  
  outdata(0x06);   //auto increment after writing 1 char; en................................... try mode
  lcd_control_write();  
   
  
}
void lcd_control_write(void){
  outcontrol(0x01);   
  delay(1);
  outcontrol(0x00);
  delay(1);
}
void write_data(char wr_data){
  outdata(wr_data);
  outcontrol(0x02);    //giving pulse to enable and sending data
  delay(1);
  outcontrol(0x03);
  delay(1);
  outcontrol(0x02);
  delay(1);
}
void set_cursor_second_row(void) {
  outdata(0xC0);  // Address of the second row in 16x2 LCD(DDRAM)
  lcd_control_write();
}
void set_cursor_first_row(void) {
  outdata(0x80);  // Address of the first row in 16x2 LCD(DDRAM)
  lcd_control_write();
}
void loop() {
  // put your main code here, to run repeatedly:
  outdata(0x1B);     // 0001 10111
  lcd_control_write();
  delay(300);

}