/*
   Forum: https://forum.arduino.cc/t/lcd-displaying-white-lines-s0lv3d/1312714
   Wokwi: https://wokwi.com/projects/412097242415977473

   Test of "LiquidCrystal_I2C.h" and "Adafruit_LiquidCrystal.h"
   by using the I2C example from

   https://github.com/adafruit/Adafruit_LiquidCrystal/blob/master/examples/HelloWorld_i2c/HelloWorld_i2c.ino

  "Adafruit_LiquidCrystal.h" connects but shows only a blank screen
  "LiquidCrystal_I2C.h" connects and displays as expected

  2024/10/18

  ec2021

*/

// Outcomment the following line to use "LiquidCrystal_I2C.h" instead of "Adafruit_LiquidCrystal.h"
#define ORIGINAL


/*
 Demonstration sketch for Adafruit i2c/SPI LCD backpack
 using MCP23008 I2C expander
 ( https://learn.adafruit.com/i2c-spi-lcd-backpack )

 This sketch prints "Hello World!" to the LCD
 and shows the time.

  The circuit:
 * 5V to Arduino 5V pin
 * GND to Arduino GND pin
 * CLK to Analog #5
 * DAT to Analog #4
*/



#ifdef ORIGINAL
  // include the library code:
  #include "Adafruit_LiquidCrystal.h"
  // Connect via i2c, default address #0 (A0-A2 not jumpered)
  Adafruit_LiquidCrystal lcd(7);
#else
  #include "LiquidCrystal_I2C.h"
  const byte I2C_ADDR    =   0x27;
  const byte LCD_COLUMNS = 16;
  const byte LCD_LINES   = 2;
  LiquidCrystal_I2C lcd(I2C_ADDR, LCD_COLUMNS, LCD_LINES);
#endif  

void setup() {
  Serial.begin(115200);
  // while(!Serial);
  Serial.println("LCD Character Backpack I2C Test.");

  // set up the LCD's number of rows and columns:
#ifdef ORIGINAL  
  if (!lcd.begin(16, 2)) {
    Serial.println("Could not init backpack. Check wiring.");
    while(1);
  }
#else
  lcd.begin(16,2);
#endif    
  Serial.println("Backpack init'd.");

  // Print a message to the LCD.
  lcd.print("hello, world!");
}

void loop() {
  // set the cursor to column 0, line 1
  // (note: line 1 is the second row, since counting begins with 0):
  lcd.setCursor(0, 1);
  // print the number of seconds since reset:
  lcd.print(millis()/1000);

  lcd.setBacklight(HIGH);
  delay(500);
  lcd.setBacklight(LOW);
  delay(500);
}