#include <Wire.h>



// Arduino     i2c-lcd

// Dig 2 ----- 1pin rst (pull-up 10k ohm)

// Ana 5 ----- 2pin scl (pull-up 2.2k ohm)

// Ana 4 ----- 3pin sda (pull-up 2.2k ohm)

// GND ------- 4pin

// 5V -------- 5pin



int ledPin = 13;

int resetPin = 2;

int sdaPin = 18; // analog pin 4

int sclPin = 19; // analog pin 5

int i2cadr = 0x3e;

byte contrast = 40; // 0-63 5V系だとかなり少なくする



void lcd_cmd(byte x)

{

  Wire.beginTransmission(i2cadr);

  Wire.write(0x00);

  Wire.write(x);

  Wire.endTransmission();

}



void lcd_data(byte x)

{

  Wire.beginTransmission(i2cadr);

  Wire.write(0x40);

  Wire.write(x);

  Wire.endTransmission();

}



void lcd_puts(const char *s)

{

  while(*s) lcd_data(*s++);

}



void lcd_init()

{

  // reset

  delay(500);

  pinMode(resetPin, OUTPUT);

  digitalWrite(resetPin, LOW);

  delay(1);

  digitalWrite(resetPin, HIGH);

  delay(10);

  // LCD initialize

  delay(40);

  Wire.begin();

  lcd_cmd(0x38); // function set

  lcd_cmd(0x39); // function set

  lcd_cmd(0x14); // interval osc

  lcd_cmd(0x70 | (contrast & 15)); // contrast low

  lcd_cmd(0x5c | (contrast >> 4 & 3)); // contrast high / icon / power

  lcd_cmd(0x6c); // follower control

  delay(300);

  lcd_cmd(0x38); // function set

  lcd_cmd(0x0c); // display on

  lcd_cmd(0x01); // clear display

  delay(2);

}



void lcd_move(byte pos){

  lcd_cmd(0x80 | pos);

}



void setup()

{

  lcd_init();

  lcd_puts("Hello, Arduino!");

  lcd_move(0x40);

  lcd_puts("i2c LCD module");

  

  pinMode(ledPin, OUTPUT); // Lチカ

}



void loop()

{

  digitalWrite(ledPin, HIGH);

  delay(100);

  digitalWrite(ledPin, LOW);

  delay(500);

}