read Description Reads one byte of data from the receive buffer. Syntax Wire.available() Parameters None Returns The number of bytes available for reading. available Description Returns the number of bytes available for retrieval in the receive buffer. Length: The number of bytes to transmit Returns Byte: Write() will return the number of bytes written, though reading that number is optional. String: A string to send as a series of bytes Wire.write(data, length) Parameters value: A value to send as a single byte Syntax unsigned char Wire.endTransmission() Parameters None Returns 0 write Description Adds a character string or data to the end of the transmit buffer. Syntax Wire.beginTransmission(unsigned char address) Parameters address: The 7-bit address of the device to which to transmit Returns None endTransmission Description Ends a transmission to a slave device that was begun by beginTransmission() and transmits the bytes that were queued by write(). Subsequently, queue bytes for transmission with the write() function and transmit them by calling endTransmission().

beginTransmission Description Begin a transmission to the I 2C slave device with the given address. Returns Byte: The number of bytes returned from the slave device. False will continually send a restart after the request, keeping the connection active. True will send a stop message after the request, releasing the bus. Quantity: The number of bytes to request. Wire.requestFrom(address, quantity, stop) Parameters address: The 7-bit address of the device from which to request bytes. Syntax Wire.requestFrom(address, quantity) The bytes may then be retrieved with the available() and read() functions. Syntax Wire.begin() Parameters None Returns None requestFrom Description Used by the master to request bytes from a slave device. Wire: 21(SCL), 20(SDA) begin Description Initiates the Wire library. Not supported for operating as a slave device.

The available channels and pin numbers are as follows and can also be confirmed on the pin map. The pull-up to communication lines is needed. This is an I 2C communications library that facilitates two-wire class communications with I 2C/TWI devices (also called 'Wire Library').

Wire library download arduino