(1) Introduction and features of I2C

I2C: I want to fully understand it from the perspective of embedded software engineers. I just applied for a column and wrote it well.
Learn the technology from the foreign documents ~~

To fully understand I2C, we can see from I2C-bus specification and user manual. I2C was initially proposed by Philips, so this document is maintained by NXP.
The I2C bus is used by more than 1000 ICS in more than 50 companies around the world and is already a world standard. in addition, the I2C bus is compatible with a variety of different control bus, such as SMBus (System Management Bus), pmbus (Power Management Bus), IPMI (Intelligent platform management Bus ), DDC (display data channel) and ATCA (advanced telecommunications architecture ). if you remember correctly, the I2C framework in Linux fully supports SMBus.
Next we need to understand how the I2C bus works and how to design it in a specific application. i2C data transmission, handshaking, and bus arbitration mechanisms all need to be understood. the timing and electrical characteristics of the I2C bus in each operating mode need to be understood. Here we will focus on timing characteristics from the perspective of embedded software engineers.
I2C bus features:
In consumer electronics, communication, and industrial electronics, there seems to be many similar designs. For example, basically every system includes:
1. Some smart controls, usually single-chip microcontroller
2. General circuits: LCD and LED Drivers, remote I/O Ports, Ram, EEPROM, RTC, or DAC \ ADC.
3. Application-oriented circuits: digital tuning and signal processing circuits for radio and video systems, temperature sensors, and smart cards.
To make these commonalities useful to system designers and equipment manufacturers, and to maximize the effectiveness of hardware and the simplicity of the circuit, Philips semiconductor developed a simple bidirectional 2-wire bus, effective control between IC. this bus is called the I2C bus. all devices compatible with the I2C bus include an on-chip interface that allows them to communicate directly through the I2C bus. this design solves many interface problems arising from the design of digital control circuits.
Below are some characteristics of the I2C bus:
1. Only two lines are required. One serial data line (SDA) has one serial clock line (SCL ).
2. You can use a software method and a unique address to find each device connected to the bus. A simple master-slave relationship exists. The host can be used as a host transmitter or a host receiver.
3. It is a real multi-host bus. If two or more hosts initiate data transmission, they can prevent data corruption through conflict detection and arbitration.
4. The serial 8-bit bidirectional data transmission reaches 3.4 kb/s in standard mode, kb/s in fast mode, and Mb/s in overspeed mode.
5. Serial 8-bit unidirectional data can reach 5 Mb/s in fast mode.
6. The on-chip filter can protect data integrity.
7. the maximum number of ICS connected to the bus is limited by the maximum capacitance of the bus.
Benefits of system designers:
Because the I2C bus is a standard bus and no additional interface is required, you can simply change the IC during system upgrade or modification.
Benefits of vendors:
The I2C bus-compliant IC not only helps designers, but also provides many benefits to equipment vendors, because:
1. I2C only has two wires, so there will be fewer pins for the IC, smaller PCB Area, and lower costs.
2. The complete I2C bus protocol does not require an address decoder or other logic circuits.
This is only some benefit. in addition, the I2C bus-compliant IC will increase the flexibility of the system design. IC is easy to upgrade. For example, if you need a larger Rom, you only need to select a microcontroller with a larger Rom.
Benefits of IC designers:
The designer of the microcontroller often needs to consider the output pin. i2C protocol allows connections to various peripherals without separately addressing signals and chip enabling signals. in addition, the microcontroller with I2C interface is more popular in the market, because many peripherals can be selected.

The first part of the translation is so much that the English level can only be like this. Next time I start to understand the I2C bus protocol ~