20 I2C Protocol Interview Questions and Answers

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 Protocol Interview Questions and Answers

Here are 20 commonly asked I2C Protocol interview questions and answers to prepare you for your interview:

1. What is I2C?

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.

2. Can you give me a little bit of history about I2C? When was it invented and what were the circumstances?

I2C was invented in 1982 by Philips Semiconductor as a way to simplify the process of connecting electronic devices. The protocol was designed to allow for communication between devices with a minimum of wiring and without the need for a dedicated communication bus. I2C has since become a standard communication protocol for a wide variety of electronic devices, including computers, smartphones, and industrial equipment.

3. Is I2C still used in modern applications? If yes, can you name some examples?

Yes, I2C is still used in many modern applications. Some examples include:

-Smartphones
-Computers
-Consumer electronics
-Industrial equipment
-Automotive applications

4. How does I2C work?

I2C is a two-wire serial communication protocol. It is used for short distance communication between devices. I2C is a synchronous protocol, meaning that it uses a clock signal to control the timing of data transfers. Data is transferred in packets, with each packet consisting of a start bit, a number of data bits, and a stop bit.

5. What are some advantages of using I2C over other protocols like SPI or UART?

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.

6. What do you understand by open collector mode?

Open collector mode is a configuration where the output of a device is not directly connected to the voltage source, but is instead connected to ground through an external resistor. This allows multiple devices to be connected to the same line and share the same ground, which is often necessary in I2C communication.

7. What’s the difference between a master and slave device on an I2C bus?

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.

8. What is arbitration? Why is it important to I2C?

Arbitration is the process of two devices on an I2C bus trying to become the master at the same time. The arbitration process is important because it ensures that only one device can be the master at any given time, preventing data collisions.

9. How many masters can be attached to an I2C bus?

I2C is a multi-master bus, meaning that multiple masters can be attached to the bus and each can initiate transactions.

10. What are pull-up resistors and why are they required?

Pull-up resistors are required in order to ensure that the signal remains high when no devices are sending a signal. Without pull-up resistors, the signal would be susceptible to noise and would not be able to be reliably read by the devices.

11. Is there any limit on the number of devices that can be connected to an I2C bus? If so, what is the maximum number of devices allowed?

There is no limit on the number of devices that can be connected to an I2C bus, as long as each device has a unique address.

12. What are the different types of I2C messages supported by the protocol?

The I2C protocol supports three different types of messages:

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.

13. Does I2C support synchronous or asynchronous communication?

I2C supports both synchronous and asynchronous communication. Synchronous communication is when the data is sent and received at the same time, while asynchronous communication is when the data is sent and received at different times.

14. Is I2C a full duplex protocol?

No, I2C is not a full duplex protocol. This means that data can only travel in one direction at a time.

15. How do you determine the direction of data transfer while sending an I2C message?

The I2C protocol uses a concept called arbitration. Arbitration is the process of two devices on the bus trying to control the bus at the same time. The I2C bus uses a system of arbitration where the device with the lowest address is given priority. This arbitration process is what allows the I2C bus to determine the direction of data transfer.

16. What happens if two or more devices try to send messages at the same time?

If two or more devices try to send messages at the same time, then a collision will occur and the devices will have to wait a certain amount of time before trying to send again.

17. What is the significance of ACK/NACK signals in I2C?

The ACK/NACK signals are used to indicate whether or not the data being sent was received correctly. If the data was received correctly, then the ACK signal will be sent. If the data was not received correctly, then the NACK signal will be sent.

18. Why do we use a watchdog timer for detecting errors in I2C transfers?

A watchdog timer is used to detect errors in I2C transfers because it can help to ensure that the data being transferred is not corrupted. If the data being transferred is corrupted, then the watchdog timer will trigger and an error will be generated. This can help to prevent data loss or corruption.

19. What type of addressing scheme does I2C use?

7-bit or 10-bit

20. Can you explain how address collisions occur in I2C?

Address collisions can occur in I2C when two devices attempt to use the same address. This can happen if the address is not unique, or if the address is not configured properly. If a collision does occur, it can cause the data transfer to be disrupted.