JHE Inter-Integrated Circuit (I2C)

Vocab: 

Inter-Integrated Circuit (I2C) - communication bus protocol

Bus - a transmission path on which signals are dropped off or picked up at every device attached to the line

What is i2c?

Set Up:

• Two wires: SDA (serial data) and SCL (serial clock)
• SDA is used to send and receive data
• SCL is the clock line which synchronizes data transfer

Steps for Transferring Data:

1. The master will send out a start sequence that alerts all the slave devices that a transaction is about to start and to keep a look out by switching all the SCL lines from high to low
2. The master then sends out the device addresses of the ones they wish to talk to (ADDR) and a Read or Write bit
3. The slaves that match those addresses will return an acknowledge bit by pulling the SDA line low by a bit
4. Send the data byte
5. Wait for the receivers (slaves) to return another acknowledge bit if the transfer was successful
6. Send the stop sequence by switch SCL to be high, then SDA to also be high