void init_port();
void out_data(char);
void out_control(char);
void delay_ms(volatile long);
void lcd_control_write();
void init_lcd();
void write_data(char);
void write_string(char *);

void setup() {
  init_port();
  init_lcd();
  write_string("Welcome");
}

void loop() {

}

void init_port() {
  volatile char *dir_f = (char*)0x30;
  volatile char *dir_k = (char*)0x107;
  *dir_f = 0xFF;
  *dir_k = 0x03;
}

void out_data(char output_data) {
  volatile char *out_f = (char*)0x31;
  *out_f = output_data;
}

void out_control(char output_data) {
  volatile char *out_k = (char*)0x108;
  *out_k = output_data;
}

void delay_ms(volatile long timer_ms) {
  volatile long j;
  for (j = 0; j < timer_ms * 428; j++);
}

void lcd_control_write() {
  out_control(0x01);
  delay_ms(3);
  out_control(0x00);
  delay_ms(3);
}

void init_lcd() {
  out_data(0x3F);          // 8 bit 2 line
  lcd_control_write();
  out_data(0x0F);          // Display ON - OFF Control
  lcd_control_write();
  for (char i = 0; i < 4; i++) {
    out_data(0x14);        // Display Shift
    lcd_control_write();
  }
}

void write_data(char wr_data) {
  out_data(wr_data);
  out_control(0x02);      // register select
  delay_ms(3);
  out_control(0x03);      // enable signal
  delay_ms(3);
  out_control(0x02);      // register select
}

void write_string(char *ptr) {
  while (*ptr != 0) {
    write_data(*ptr);
    ptr++;
  }
}