The important functions of this library are given below −

The following pins are generally used for SPI −Īrduino has a built-in Wire library. Start/Stop sequence is required to signal start and end of communication If they want to send high level, they simply release the bus. two resistors pull the bus to a high level and the devices only send low levels. The data and clock lines are pulled up, i.e. The slave has to make sure that the next bit is ready when the clock pulse arrives If the master wants to receive the data, it only generates clock pulses. Thus a maximum of 127 slaves with unique addresses can be connected to a single master.Īfter each byte, the receiver must send a 0 to acknowledge the reception of the byte The first byte sent by the master contains a seven-bit address and a read/ write bit indicating whether the next bytes will come from the master or should come from the slave. The slaves are not selected via a slave select line, but via address bits. I2C is synchronous because it uses a clock. It uses only two lines: One for data (SDA) and one for clock (SCL). Arduino refers to I2C as Wire, which is a shorter form of the term Atmel uses (Two Wire Interface or TWI). It is a popular communication protocol used by several peripherals like accelerometer and gyroscopes, OLED Displays, etc.

Arduino wire library read from register