Introduction
The I2C protocol (Inter-Integrated Circuit) is a serial communication standard that is used to connect microcontrollers and peripheral devices. It uses a master-slave architecture, which allows numerous peripherals to communicate over two wires: a data line (SDA) and a clock line (SCL). Individual devices are addressed, allowing for efficient data flow at varied speeds. I2C simplifies and versatilely allows bidirectional data transfer, synchronous clocking, and various sensor and integrated circuit interfaces in embedded systems.
What is the I2C communication Protocol?
- I2C stands for Inter-Integrated Circuits. I2C protocol is also known as Two Wire Interface (TWI).
- I2C is used for serial communication.
- There is communication between only 2 wires.
- i) SDA – Serial Data Line ii) SDL – Serial Clock Line
- User can integrate 128 devices with just two lines.
- I2C is simple for a user to use and is used for short-range communication.
- It is a low-bandwidth protocol.
- It comprises of Master–Slave with multiple masters and multiple slaves combination possible. The most commonly used type is Single Master and multiple Slaves.
- Master has the capability to Read and Write the data.
- If the number of devices increases then the capacitance of the circuit also increases. Therefore, the number of devices is limited by the total allowed capacitance of 400 micro-Faraday.
Process for establishing I2C protocol :
- First there is the start condition.
Go from High voltage level to Low voltage level. First, do with the SDA line and then the SCL line.
- For a circuit with a single Master and multiple Slaves, the Master sends “ Slave Address + Read/Write bit ” to each Slave. Every Slave compares their Slave address with their own address.
- The matched Slave sends Ack (Acknowledge) bit.
Ack bit = Logic 0 à When Slave is ready
Ack bit = Logic 1 à When Slave is Not ready
This is done by making 1 bit of the SDA line low.
- Now Master sends data to the Slave in terms of Data frames.
- For every data frame received, Ack bit is sent by the receiver.
- Apply Stop condition
First, make the SCL line from Low to High.
Then make the SDL line from Low to High.
Advantages and Limitations :
Advantages –
- Simplicity – I2C is a two-wire design that makes it simple to implement and integrate multiple devices.
- Reduced pin count – The devices on the I2C bus do share a common clock and data lines. Therefore the number of pins needed for communication as compared to other protocols is less.
- Addressing Flexibility – I2C supports both 7-bit and 10-bit addressing modes. It allows a large number of devices to co-occur on the same bus.
- Low Power Consumption – I2C is designed for low-power communication. Therefore it is useful for battery-operated devices and energy-efficient devices.
- Short Distance Communication – I2C is useful for short-range communication. Therefore it is useful for compact devices.
Limitations –
- Limited Speed – It is operated at lower data rates as compared to other protocols like UART or SPI. It may not be suitable for high-speed communication.
- Distance Limitations – I2C is designed for short-range communication with a single PCB. It is not suitable for long-distance communication.
- Limited Bandwidth – The available bandwidth is divided among all the devices present on the bus.
- Limited Address Space – I2C supports 7-bit and 10-bit addressing modes. It may not fulfill the need for large systems with many devices.
- Clock Synchronization – An accurate clock synchronization between Master and Slave is very important for proper communication.
Applications of I2C Protocol :
- Smartphones and Tablets
- TV
- Microcontrollers and Microprocessors
- Arduino and Rasberry Pi projects
- In medical devices like Patient Monitoring
- Network Switches and Routers
- Ethernet PHY (Physical layer) chips
- Smart Thermostats
- Home Automation
- Game Controllers
- Smartwatches and Fitness Trackers
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