Arduino i2c Wire.h library

Wire Library

This library allows you to communicate with I2C / TWI devices.
On most Arduino boards,
SDA (data line) is on analog input pin 4, and
SCL (clock line) is on analog input pin 5.
On the Arduino Mega, SDA is digital pin 20 and SCL is 21.

Functions

• begin()
• begin(address)
• requestFrom(address, count)
• beginTransmission(address)
• endTransmission()
• send()
• byte available()
• byte receive()
• onReceive(handler)
• onRequest(handler)

Note

There are both 7- and 8-bit versions of I2C addresses.
7 bits identify the device, and the eighth bit determines
if it's being written to or read from.
The Wire library uses 7 bit addresses throughout.
If you have a datasheet or sample code that uses 8 bit address,
you'll want to drop the low bit (i.e. shift the value one bit to the right),
yielding an address between 0 and 127.