Reference for Wiring version 0027+. If you have a previous version, use the reference included with your software. If you see any errors or have any comments, let us know.

Class

Wire

Name

begin()

Examples
#include "Wire.h"

void setup()
{
  // join i2c bus (address optional for master)
  Wire.begin();
  // start serial for output  
  Serial.begin(9600);
}

void loop()
{
  // request 6 bytes from slave device #2
  Wire.requestFrom(2, 6);    

  // slave may send less than requested
  while(Wire.available())    
  { 
    // receive a byte as character
    char c = Wire.receive(); 
    Serial.print(c);  // print the character
  }

  delay(500);
}

#include "Wire.h"

void setup()
{
  // join i2c bus with address #4
  Wire.begin(4);    
  // register event  
  Wire.onReceive(receiveEvent); 
  // start serial for output
  Serial.begin(9600);
}

void loop()
{
  delay(100);
}

// function that executes whenever data is received from master
// this function is registered as an event, see setup()
void receiveEvent(int howMany)
{
  // loop through all but the last
  while(1 < Wire.available()) 
  {
    // receive byte as a character
    char c = Wire.receive(); 
    Serial.print(c);  // print the character
  }
  // receive byte as an integer
  int x = Wire.receive();    
  Serial.println(x);  // print the integer
}
Description The Wiring TwoWire library allows for easily reading and writing data to external devices using the Two Wire Interface (TWI or I2C) protocol. The TWI protocol and interface were developed by Phillips. The TWI pins are available on the Wiring I/O board on pins 0 (SCL) and 1 (SDA). It is possible to connect multiple TWI devices to the TWI pins creating a network or bus of devices and communicate with them by means of an address. The TWI can be configured to act as a Master or a Slave in a network of devices. The begin() method is used to initiate the TWI as a Master and the begin(address) method is used to join the TWI bus a slave using the address specified. In both cases the begin method must be must be placed in the setup() method.
Syntax
Wire.begin()
Parameters
address An integer value between 0 and 127 specifying the address to be used when joining the TWI bus.
Wire The hardware TWI port
Returns None
Usage Application
Updated on September 18, 2010 03:23:32pm PDT

Creative Commons License