“In an interview, questions are the bridges between a candidate’s experiences and an employer’s expectations. They pave the way for understanding, insight, and the journey towards finding the perfect professional match. Before entering into UART interview questions, it is suggested to go through the UART protocol tutorial at least once. UART, or Universal Asynchronous Receiver-Transmitter, is a communication protocol used for serial communication between devices. It involves the transmission of data between devices bit by bit, without a shared clock signal.
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UART
UART is commonly employed in various applications, serving functions such as connecting microcontrollers to other peripherals, facilitating communication between embedded systems, and interfacing with sensors and other hardware components. Moreover, its versatility extends across a spectrum of use cases. Additionally, this adaptability positions UART as an integral component in diverse fields, showcasing its significance in fostering seamless communication within a wide range of electronic systems
The protocol defines the format of the data being sent, including start and stop bits, data bits, and optional parity for error checking. Additionally, UART provides a simple and versatile method for devices to exchange information serially. Moreover, this inherent flexibility and ease of implementation make it a widely adopted communication standard in various applications, ranging from microcontroller communication to data logging and industrial automation.
UART Interview Questions 01 to 07
What is the Abbreviation of UART? or What is the Full Form of UART
UART (Universal Asynchronous Receiver Transmitter)
What is UART?
UART is a serial communication protocol. In addition, it operates as full-duplex communication, allowing simultaneous transmission and reception of data. Furthermore, UART incorporates a shift register, serving as the fundamental method for converting between serial and parallel forms of data. This combination of features makes UART a versatile and widely used protocol in various electronic communication applications.
Serial Communication or parallel communication?
UART communication serial communication.
Synchronous communication or asynchronous communication?
UART communication is asynchronous communication.
UART is half-duplex communication or full-duplex communication?
UART is a full duplex communication.
How many lines or wires are needed for UART Communication?
Three Wires are need for UART Communication
What wires are in UART Communication?
- RX (Receiver Line),
- TX (Transmission Line),
- Ground
UART Interview Questions 08 to 10
Draw the UART Packet format.
What are the different types of packet fields in the UART frame?
- Start bit
- Stop bit
- Data bits
- Parity bits
What is the start bit in UART? and How to detect start bit in UART Communication?
The UART data transmission line is normally held at a high voltage level when it’s not transmitting data. To start the transfer of data, the transmitting UART pulls the transmission line from high to low for one clock cycle. Upon detecting the high to low voltage transition, the receiving UART begins reading the bits in the data frame at the frequency of the baud rate. The start bit, logically low, signals the receiver that a new character is coming.
UART Interview Questions 11 to 14
Start bit size is one or two in UART?
In UART, the start bit size is typically set to one. The start bit serves as the initial element in the data frame, indicating the beginning of a new character. Moreover, while two stop bits are also an option in UART configurations, the common practice is to use a single start bit for efficient and standard serial communication.
What is a stop bit in UART? or How to detect a stop bit in UART Communication?
To signal the end of the data packet, the sending UART drives the data transmission line from a low voltage to a high voltage for at least two-bit duration. Additionally, this transition marks the conclusion of the data frame, ensuring a clear and recognizable endpoint in UART communication.
How many stop bits are available in UART?
UART commonly supports one or two stop bits. The number of stop bits is a parameter in UART communication and is typically configured based on system requirements. In standard UART configurations, one stop bit is more common, but some applications, especially in older or specific systems, may use two stop bits for added reliability. This flexibility in stop bit configuration allows UART to adapt to various communication needs and system specifications.
What is the stop bit size in UART?
1 bit, 1.5bit and 2bits can be configurable in UART. Its based on micro controller feature and PC tool options.UART commonly supports either one or two stop bits. The stop bit size is a configurable parameter in UART communication, allowing flexibility based on system requirements. In determining the appropriate stop bit configuration, factors such as the desired level of reliability and compatibility with other devices or protocols come into play.
UART Interview Questions 15
What is the parity bit in UART?
Parity describes the evenness or oddness of a number. The parity bit is a way for the receiving UART to tell if any data has changed during transmission. Bits can be altered by various factors, such as electromagnetic radiation, mismatched baud rates, or long-distance data transfers. After the receiving UART reads the data frame, it counts the number of bits with a value of 1 and checks if the total is an even or odd number. If the parity bit is set to 0 (even parity), the 1 bits in the data frame should total an even number. Conversely, if the parity bit is set to 1 (odd parity), the 1 bits in the data frame should total an odd number. When the parity bit matches the data, the UART recognizes that the transmission was error-free. However, if the parity bit is 0 and the total is odd or the parity bit is 1 and the total is even, the UART detects that bits in the data frame have changed.
UART Interview Questions 16 to 17
What is the Baud Rate of UART support?
UART supports a variety of baud rates, ranging from 300 to 3686400, including common rates such as 600, 1200, 2400, 4800, 9600, 19200, 38400, 57600, 74880, 115200, 230400, 256000, 460800, 921600, 1843200, and 3686400.
UART Speed can be configurable?
Yes, Speed can be configurable. Both receiver and transmitter side need to set the same baud rate
UART Interview Questions 18 to 21
How to set UART Speed in the transmitter and Receiver?
Both receiver and transmitter side need to set the same baud rate, In Mictro Controller respective Bard rate set registor need to load the same baudrate
If the bit rate is 9600, how many bytes can be transmitted per second?
The below link explains three major baud rate timings
Which part of the data sends first in UART? or is LSB or MSB sent first in UART?
LSB is always first and MSB is last. For example decimal 5 is the binary form of 0b00000101. Here LSB will be first and followed by MSB like 10100000.
What is the maximum length of the UART Cable that can communicate?
Data transmission over a distance of 15 meters at 9600 bits/s is feasible. However, in my real-time applications, I have successfully employed up to a 2-meter RJ45 cable.
UART Interview Questions 22 & 23
What devices use the UART protocol?
- GPS module like SIM900/800 uses UART protocol.
- The fingerprint sensor uses the UART protocol.
- RFID modules use the UART protocols and many more.
What are the interrupts in UART
- RX Interrupt,
- TX Inetrrupt,
- Parity Error Interrupt,
- Framming Error Interrupt,
- Over Run Error Interrup,
- Break Detect Interrupt,
- Wakeup Interrupt.
Questions 24
What are the Errors in UART?
- Parity errors (PE),
- Frame errors (FE),
- Break Detect errors (BRKDT),
- Overrun errors (OE),
- Bit errors (BE)
UART Advantages and disadvantages?
Use of UART
| Area | Use |
|---|---|
| Microcontroller Communication | Enables communication between microcontrollers and peripheral devices for seamless data exchange. Furthermore, this capability enhances the overall efficiency and functionality of interconnected systems. |
| Embedded Systems | Facilitates communication between different modules or subsystems within embedded systems, enhancing overall functionality. Moreover, this streamlined communication contributes to the cohesive operation of embedded systems, optimizing their performance. |
| Serial Communication between Devices | Establishes serial communication between devices like GPS modules, Bluetooth modules, RFID readers, and other hardware components. |
| Console Communication | Serves as a standard interface for communication between computers and external devices such as routers, switches, and network equipment. |
| Wireless Communication | Used in wireless communication modules (e.g., GSM, Wi-Fi) for data transmission, crucial in IoT applications. |
| Programming and Debugging | Essential for programming and debugging microcontrollers, allowing firmware transfer and real-time debugging. |
| Industrial Automation | Utilized in industrial automation for communication between PLCs, HMIs, and control devices, UART plays a pivotal role in ensuring seamless data exchange within the intricate network of devices in manufacturing and process control systems. |
| Data Logging | Applied in data logging applications where UART facilitates the transmission of information from sensors to data loggers. |
Next: https://aruneworld.com/embedded/embedded-protocol/uart/