#include <Wire.h>
#include <LiquidCrystal_I2C.h>

#define LINE_LENGTH 16
#define BUF_LENGTH 64

LiquidCrystal_I2C lcd(0x3F, LINE_LENGTH, 2);

static char input_buf[BUF_LENGTH];
static int input_i = 0;

void setup() {
  lcd.init();  //initialize the lcd
  lcd.backlight();  //open the backlight
  Serial.begin(9600);
}


void update_screen() {
  char line1[LINE_LENGTH+1];
  char line2[LINE_LENGTH+1];
  int n;

  n = sscanf(input_buf, "%[^;];%[^;]", line1, line2);

  lcd.clear();

  switch (n) {
    case 2:
      // line2 (optional)
      lcd.setCursor(0, 1);
      lcd.print(line2);
    case 1:
      // line1
      lcd.setCursor(0, 0);
      lcd.print(line1);
      break;
    case 0:
    default:
      lcd.setCursor(0, 0);
      lcd.print("Error!");
      break;
  }
}


void loop() {
  char c;

  if (Serial.available()) {
    c = Serial.read();
    if (input_i == BUF_LENGTH-1 || c == '\n') {
      input_buf[input_i] = '\0';
      input_i = 0;
      update_screen();
    } else {
      input_buf[input_i] = c;
      input_i++;
    }
  }
}