Interview questions on I2C protocol Part 1
What does I2C stand for?
In I2C only two buses are required for the communication, the serial data bus (SDA) and serial clock bus (SCL).
I2C is half-duplex or full-duplex?
I2C is pure master and slave communication protocol, it can be the multi-master or multi-slave but we generally see a single master in I2C communication. In I2C only two-wire are used for communication, one is data bus (SDA) and the second one is the clock bus (CLK).
All slave and master are connected with same data and clock bus, here important thing is to remember these buses are connected to each other using the WIRE-AND configuration which is done by to putting both pins is open drain. The wire-AND configuration allows in I2C to connect multiple nodes to the bus without any short circuits from signal contention.
The open-drain allows the master and slave to drive the line low and release to high impedance state. So In that situation, when master and slave release the bus, need a pull resistor to pull the line high. The value of the pull-up resistor is very important as per the perspective of the design of the I2C system because the incorrect value of the pull-up resistor can lead to signal loss.
Note: We know that I2c communication protocol supports multiple masters and multiple slaves, but most system designs include only one master.
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The I2C Protocol is a communication standard that allows devices to exchange data with each other. It is commonly used in embedded systems and allows for a variety of devices to be connected to a single bus. When interviewing for a position that uses I2C, it is important to be prepared to answer questions about the protocol. In this article, we will review some common I2C questions and how you should answer them.
I2C is a two-wire serial bus protocol that is used for communication between devices. I2C is a synchronous protocol, which means that it uses a clock signal to control the timing of data transfers. I2C is a multi-master protocol, which means that multiple devices can be connected to the bus and can act as either a master or a slave. I2C is a half-duplex protocol, which means that data can only be transferred in one direction at a time.
I2C is a very versatile protocol that can be used for a variety of different applications. One big advantage that I2C has over other protocols is that it only requires two wires to operate, which can save a lot of space and resources. I2C is also very flexible in terms of speed and data transfer rates, which makes it ideal for a variety of different applications.
1. Standard messages are used for most data transfers and have a data rate of up to 100 kbps. 2. Fast-mode messages are used for higher-speed data transfers and have a data rate of up to 400 kbps. 3. High-speed messages are used for the highest-speed data transfers and have a data rate of up to 3.4 Mbps.
The master device is the one that initiates all of the communication on the I2C bus. It is responsible for sending out the start signal, and it also controls the clock signal that all of the other devices on the bus use to synchronize their communication. The slave devices are the ones that respond to the master’s commands. They do not have any control over the bus, and they cannot initiate communication.
Explain the operation and frame of I2C protocol
I2C is a chip to chip communication protocol. In I2C, communication is always started by the master. When the master wants to communicate with slave then he asserts a start bit followed by the slave address with read/write bit.
After asserting the start bit, all slave comes in the attentive mode. If the transmitted address match with any of the slave on the bus then an ACKNOWLEDGEMENT (ACK) bit is sent by the slave to the master.
After getting the ACK bit, master starts the communication. If there is no slave whose address match with the transmitted address then master received a NOT-ACKNOWLEDGEMENT (NACK) bit, in that situation either master assert the stop bit to stop the communication or assert a repeated start bit on the line for new communication.
When we send or receive the bytes in i2c, we always get a NACK bit or ACK bit after each byte of the data is transferred during the communication.
In I2C, one bit is always transmitted on every clock. A byte which is transmitted in I2C could be an address of the device, the address of register or data which is written to or read from the slave.
In I2C, SDA line is always stable during the high clock phase except for the start condition, stop condition and repeated start condition. The SDA line only changes their state during the low clock phase.
See the below ,
Start Bit: Start the communication
Stop bit: Stop communication.
FAQ
What is I2C protocol used for?
- What is I2C communication? …
- What does I2C stand for? …
- How many wires are required for I2C communication? …
- I2C is half-duplex or full-duplex? …
- I2C is Synchronous or Asynchronous Communication? …
- Explain the physical layer of the I2C protocol. …
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What are the 2 roles of nodes in I2C communication?
What is the maximum speed of I2C?
