This Tuesday the subject of our article is a master and a slave functions of the USB I2C system.
Inter-Interface Circuit (abbreviated to I2C (the most common abbreviation), IIC or Inter-IC) is a two wire interface with a single-ended computer bus. This USB I2C/GPIO/SPI Interface Adapter was invented by Philips Company at the end of 20th century.
USB I2C/GPIO device consists of a master and a slave. Each of the I2C device plays a designated role.
But the USB I2C Interface Adapter can have several slave and only one master. A master can become any of devices (according to the protocol), which are reside on the one circuit board.
The USB I2C master device generates the clock of each transmitted bit and the USB I2C slave has to follow the speed, which was set up by a master.
And when the slave needs to have a rest for some time it just hold down the clock line and release it when it is ready to continue the communication. An I2C master can send data to several different slaves, but I2C slaves will receive it in a logical order, as the USB I2C system has one line (SDA) for conveying and receiving data from master to slave and vice versa.
An I2C single master and an I2C slave (in most cases) can be implemented on a microcontroller.
A master can drive the communication whenever it wants, as all task should proceed from a master and a slave fulfills it. When a slave receives a request from a master, it should answer it immediately.
That is the system according to which a master and a slave communicate.