20 SPI Protocol Interview Questions and Answers

SPI Protocol, or Serial Peripheral Interface Protocol, is a communication standard used for short distance data transfer. This protocol is commonly used in embedded systems and applications where low pin count and simplicity are required. When interviewing for a position that uses SPI Protocol, it is important to be prepared to answer questions about your experience and knowledge of the protocol. In this article, we will review some common SPI Protocol questions and how you should answer them.

SPI Protocol Interview Questions and Answers

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

1. What is SPI?

SPI is a communication protocol that allows for the exchange of data between devices. It is a full-duplex protocol, meaning that data can be sent and received simultaneously. SPI is commonly used in embedded systems and is one of the most popular protocols for communication between devices.

2. Can you explain the SPI bus in detail?

The SPI bus is a synchronous bus that allows for communication between devices. It is typically used for short distance communication, and operates at high speeds. The bus consists of four wires: clock, data in, data out, and chip select. The clock signal is used to synchronize the data transfer between devices, while the data in and data out signals are used to transfer data. The chip select signal is used to select the device that the master is communicating with.

3. What do you understand about serial peripheral interface?

SPI is a synchronous serial communication protocol that allows for the transfer of data between devices. It is typically used for short-distance communication between devices such as microcontrollers and sensors.

4. What are some important features of SPI? Why should we use it?

SPI is a synchronous serial communication protocol that is widely used in a variety of applications. Some of the important features of SPI include its high data transfer rate, its low pin count, and its compatibility with a wide range of devices. SPI is a popular choice for many applications because it is relatively simple to use and it can support a high data transfer rate.

5. How does an SPI work?

SPI is a synchronous serial communication protocol that allows for the exchange of data between two devices. SPI uses four wires to connect the two devices: two for data, one for a clock signal, and one for chip select. The clock signal is used to synchronize the data transfer between the two devices, and the chip select signal is used to enable or disable the connection between the two devices.

6. What are the different types of transfers that can be performed using the SPI protocol?

There are four different types of SPI transfers:

1. Single: A single transfer is the most basic type of SPI transfer, and involves the transfer of a single byte of data.
2. Dual: A dual transfer is similar to a single transfer, but involves the transfer of two bytes of data.
3. Quad: A quad transfer is similar to a dual transfer, but involves the transfer of four bytes of data.
4. Extended: An extended transfer is the most complex type of SPI transfer, and can involve the transfer of up to 64 bytes of data.

7. What are the main components that make up an SPI system?

The main components of an SPI system are the master device, the slave device, and the SPI bus. The master device is the one that initiates and controls the SPI transactions. The slave device is the one that responds to the commands from the master device. The SPI bus is the communication channel between the master and slave devices.

8. Is it possible to have more than one master and slave on a single SPI bus? If yes, then how many?

Yes, it is possible to have more than one master and slave on a single SPI bus. There is no limit to the number of masters or slaves that can be on a single bus, as long as they are all properly configured.

9. What’s the difference between synchronous and asynchronous communication protocols?

Synchronous communication protocols require that both sides of the conversation are available at the same time in order to exchange information. Asynchronous communication protocols allow for communication to take place even if both sides are not available at the same time. This can be useful when one side needs to send a large amount of data and can take longer to do so.

10. What’s the difference between SPI and I2C? Which one would you recommend for certain situations?

SPI is a synchronous serial communication protocol while I2C is an asynchronous serial communication protocol. I2C is typically used for lower data rate applications while SPI is used for applications requiring higher data rates. I2C requires less wires and pins than SPI and is typically easier to use. SPI is faster than I2C and is better suited for applications where data integrity is important.

11. Why is SPI preferred over other similar protocols like USB or UART?

SPI is preferred over other protocols like USB or UART because it is a much faster protocol. SPI can run at speeds up to 10 MHz, whereas USB and UART are limited to around 1 MHz. SPI is also a full-duplex protocol, meaning that data can be sent and received at the same time, whereas USB and UART are half-duplex, meaning that data can only be sent or received, but not both at the same time.

12. How are data transferred on a SPI bus?

Data is transferred on a SPI bus in a full-duplex manner, meaning that data can be transferred in both directions at the same time. Data is first transferred from the master device to the slave device, and then from the slave device back to the master device.

13. Can you describe how voltage levels are controlled when transferring data using an SPI?

When data is transferred using SPI, the voltage levels are controlled by a master device. The master device will generate the clock signal that controls the timing of the data transfer, and it will also send the data that is to be transferred. The slave devices will receive the data and clock signal from the master, and they will respond accordingly.

14. In which direction does the clock signal flow when using the SPI protocol?

The clock signal always flows from the master device to the slave device.

15. Does the SPI protocol support bi-directional data transfer?

Yes, the SPI protocol supports bi-directional data transfer. This means that data can be sent and received simultaneously on the same bus.

16. Can multiple devices share a common MOSI line?

Yes, multiple devices can share a common MOSI line. This is often done in order to save on costs and board space.

17. What are the limitations and drawbacks of the SPI protocol?

One of the main limitations of SPI is that it is a synchronous protocol, which means that both devices need to be synchronized in order to communicate. This can be a challenge when trying to communicate with devices that have different clock speeds. Additionally, SPI is a full-duplex protocol, which means that data can be sent and received at the same time. However, this also means that there is the potential for data collisions if the devices are not properly configured.

18. What are some examples of hardware systems that use SPI?

SPI is used in a variety of hardware systems, including but not limited to:
-Computer hard drives
-Flash memory
-Sensors
-Digital cameras
-GPS units
-Printers

19. What is the best way to achieve high performance with SPI?

One way to achieve high performance with SPI is to use a DMA controller. This will allow you to transfer data directly between memory and the SPI peripheral without having to go through the CPU. This can free up the CPU for other tasks and can result in a significant performance increase.

20. What changes should be made to the original SPI specification if you wanted to add another device to the bus?

If you wanted to add another device to the bus, you would need to add another chip select line to the bus. This would allow you to select which device you want to communicate with. You would also need to add an additional data line to the bus so that the new device can send and receive data.