What is the difference between serial begin() and wire.setClock() for I2C communication? I am a new Arduino IDE user and have a simple question below
For I2C transmission speed setting, there are serial begin() and wire.setClock(). Some sample codes just use Serial.begin() without Wire.seClock(), some use both as shown below. What is the real differences between them? When to use just serial and when to use both of them? Thanks.
void setup() {
  Serial.begin(9600);          // start serial communication at 9600bps

  Wire.begin();                // join i2c bus (address optional for master)

  Wire.setClock(400000); //Increase  I2C clock rate to 400 kHz
}
Serial has nothing to do with Wire/I2C communication. The examples only have this, because mostly they use Serial out- and input for interaction in the example codes (like showing the data of an I2C sensor on the Serial Monitor).
If you don't want to use the Serial Montior/Serial communication, then you can leave all the calls to Serial out.