gistfile1.c

/* 
   Подключение AT2424C15 по I2C
*/ 

#define ADDR  0x50

void setup() {
  Wire.begin();
  Serial.begin(38400);
  randomSeed(analogRead(0));  
}

void readByte(unsigned int addr) {
  Wire.beginTransmission(ADDR);
  Wire.send( (byte) addr >> 8 );
  Wire.send( (byte) addr & 0xff );
  Wire.endTransmission();
  Wire.requestFrom(ADDR, 1);
}

void writeByte(unsigned int addr, byte b) {
  Wire.beginTransmission(ADDR);
  Wire.send( (byte) addr >> 8 );
  Wire.send( (byte) addr & 0xff );
  Wire.send ( b );
  Wire.endTransmission();
}

void loop() {
  if (Wire.available()) {
    Serial.println(Wire.receive(),HEX);
  }
  int cmd = Serial.read();
  if (cmd != -1) {
    if (cmd == 'R') {
      readByte(0);
    }
    if (cmd == 'W') {
      long b = random(0,255);
      writeByte(0,b);
      Serial.println(b,HEX);
    }
  }  
}