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Special terms
Description
Multiple
masters
Multiple masters that control the bus at the same time without destroying
information
Synchronous
The process of synchronizing the clock signals between two or more devices
Arbitration
If more than one master tries to control the bus at the same time, only one master
can control the bus, and the information of the controlled master will not be
destroyed
I2C physical layer
The commonly used connection modes between I2C communication
devices are shown in the figure below:
Figure 83 Commonly Used I2C Communication Connection Diagram
I2C master
I2C slave 1
I2C slave 2
I2C slave 3
3.3V
3.3V
Pull-up
resistor
SCL bus
SDA bus
Characteristics of physical layer:
Bus supporting multiple devices (signal line shared by multiple devices),
which, in I2C communication bus, can connect multiple communication
masters and communication slaves.
An I2C bus only uses two bus lines, namely, a bidirectional serial data
line (SDA) and a serial clock line (SCL). The data line is used for data
transmission, and the clock line is used for synchronous receiving and
transmission of data.
Each device connected to the bus has an independent address (seven
or ten bits), and the master addresses and accesses the slave device
according to the address of the device.
The bus needs to connect the pull-up resistor to the power supply. When
I2C bus is idle, the output is in high-impedance state. When all devices
are idle, the output is in high-impedance state, and the pull-up resistor
pulls the bus to high level.