UART Question & AnswersJuly 26, 2021 By WatElectronics This article lists 100 UART MCQs for engineering students. All the UART Questions & Answers given below includes solution and link wherever possible to the relevant topic.A UART stands for Universal Asynchronous Receiver Transmitter. As the name suggests, it is an asynchronous type of communication protocol. When two devices need to communicate with each other, there need to be at least two connections between them, one is a transmission line and another one is a reception line for each device. A UART uses two wires between transmitter and receiver, and the UART frame consists of data, start/stop, and parity bits. The control, status, transmit, and receive registers are the UART registers. The control register contains settings for the UART, and the status register contains information about the UART state or condition.The Transmit Data Register Empty is a type of UART flag and the Serial Communication Status Register is a type of UART register. The UART is a widely used method, it uses only two wires, whereas the clock signal is not necessary. The disadvantages of a UART are it doesn’t support multiple slaves, and the data frame size is limited to a 9 bits max. In UART the data is transmitted in the form of bytes, its maximum speed is 115.2Kbps, and its data rate is 20Kbps. The transmitter section of a UART consists of a transmitter shift register and transmitter hold register. The Bluetooth modules, GPS units, microcontrollers, etc are the applications of a UART.1). How many wires does UART use? One Two Three Four HintUART uses two wires between transmitter and receiver2). The UART frame consists of ___________ bits Data Start/stop Parity All of the above HintThe UART frame consists of data, start/stop, and parity bits3). Which bit is used for error detection? Data Start/stop Parity All of the above HintThe parity bit is used for error detection4). In which parity the number of 1’s must be even? Even Odd Both a and b None of the above HintIn even parity the number of 1’s must be even5). ____________ are the UART registers Control and status Receive Transmit All of the above HintThe control, status, transmit and receive registers are the UART registers6). Which one of the following registers contains settings for the UART? Control Receive Transmit All of the above HintThe control register contains settings for the UART7). Which one of the following registers contains information about the UART state or condition? Control Receive Transmit Status HintThe status register contains information about the UART state or condition8). The universal asynchronous receiver transmitter can be _____________ Simplex Full-duplex Half-duplex All of the above HintThe universal asynchronous receiver transmitter can be simplex, full-duplex, and half-duplex9). In which parity the number of 1’s must be odd? Even Odd Both a and b None of the above HintIn odd parity, the number of 1’s must be odd10). The number of bits sent every second is known as ________ rate Bit Byte Baud None of the above HintThe number of bits sent every second is known as the bit rate11). The number of symbols sent every second is known as ________ rate Bit Byte Baud None of the above HintThe number of symbols sent every second is known as the baud rate12). Which one is a type of UART flag? TDRE RSR RDR None of the above HintThe TDRE is a type of UART flag13). Which one is a type of UART register? TDRE RSR SCSR None of the above HintThe SCSR is a type of UART register14). What is the standard form of TDRE? Transmit Data Register Empty Transmit Data Rate Empty Transmit Data Register Enable None of the above HintThe standard form of TDRE is Transmit Data Register Empty, it is one type of UART flag15). ____________ is an example for data communication equipment Modem Computer Terminal None of the above HintThe modem is an example of data communication equipment16). What is the standard form of DTE? Data Transfer Equipment Data Terminal Equipment Data Transmit Equipment None of the above HintThe standard form of DTE is Data Terminal Equipment17). What is the standard form of RDRF? Receiver Data Register Full Receiver Data Rate Full Register Data Receiver Full None of the above HintThe standard form of RDRF is Receiver Data Register Full18). ____________ is an example for data terminal equipment Terminal Computer Both a and b None of the above HintThe computer and terminal both are the examples for data terminal equipment19). What is the standard form of DCE? Data Communication Equipment Data Common Equipment Data Control Unit Equipment None of the above HintThe standard form of DCE is Data Communication Equipment20). What are the advantages of UART? Uses only two wires Widely used method Clock signal is not necessary All of the above HintThe UART is a widely used method, it uses only two wires, and the clock signal is not necessary for UART21). What is the standard form of RDR? Receiver Data Register Register Data Receiver Receiver Shift Register None of the above HintThe standard form of RDR is Receiver Data Register, it is a type of UART register22). What are the disadvantages of UART? Doesn’t support multiple slave Data frame size is limited to a 9 bits max Both a and b None of the above HintThe disadvantages of a UART are it doesn’t support multiple slaves, and the data frame size is limited to a 9 bits max23). What is the function of the UARTn_TXD signal? Serial data transmit-receive Clear to send handshaking signal Both a and b None of the above HintThe function of the UARTn_TXD signal is serial data transmit-receive24). The transmitter section of an UART consists of __________ Transmitter shift register Transmitter hold register Both a and b None of the above HintThe transmitter section of a UART consists of transmitter shift register and transmitter hold register25). What is the standard form of RSR? Receiver Data Register Register Shift Receiver Receive Shift Register None of the above HintThe standard form of RSR is Receive Shift RegisterUART MCQ's with Answers26). What is the function of UARTn_RTX? Serial data receive Clear to send handshaking signal Both a and b None of the above HintThe function of UARTn_RTX is Serial data receive27). Which one of the following was used to enable or disable the interrupt request? IER IIR Both a and b None of the above HintThe IER is used to enable or disable the interrupt request28). Which one of the following is a write-only register? FIFO control register Interrupt identification register Both a and b None of the above HintThe FIFO control register is a write-only register29). What is the standard form of TDR? Transport Data Register Transmit Data Register Transmit Data Receiver None of the above HintThe standard form of TDR is Transmit Data Register30). Which one of the following is a divisor latch? DLH DLL Both a and b None of the above HintBoth DLH and DLL are the divisor latches31). The baud rate of 8-bit UART is ___________ 1200bps 1500bps 9600bps None of the above HintThe baud rate of 8-bit UART is 9600bps32). In 8-bit UART 1 byte is equal to ____________ bits Two Four Eight Sixteen HintIn 8-bit UART 1 byte is equal to eight bits33). The bits transferred per second is _______ in 8-bit UART 1,000 5,098 8,192 6,789 HintThe bits transferred per second is 8,192 in 8-bit UART34). The data in a UART is detected by __________ Counter Clock Both a and b None of the above HintThe data in a UART is detected by clock Read more about UART 35). What is the standard form of TSR? Transmit Shift Register Transport Status Register Transmit Status Receiver None of the above HintThe standard form of TSR is Transmit Shift Register36). The baud rate of 16 bit UART is ___________ 1200bps 1500bps 9600bps None of the above HintThe baud rate of 16 bit UART is 9600bps37). In 16-bit UART 1 byte is equal to ____________ bits Two Four Eight Sixteen HintIn 16-bit UART 1 byte is equal to 16 bits38). The bits transferred per second is ______ in 16 bit UART 12,898 15,089 96,230 16,384 HintThe bits transferred per second is 16,384 in 16 bit UART39). Which register does UART contain? Clock Shift Both a and b None of the above HintA universal asynchronous receiver transmitter contains a shift register40). What is the standard form of SCCR? Serial Communication Control Register Serial Communication Common Register Serial Communication Register None of the above HintThe standard form of SCCR is Serial Communication Control Register, it is a type of UART register41). _________ are the handshaking signals RI, DCD, CTS DSR, RTS DTR All of the above HintThe RI, DCD, CTS, DSR, RTS, DTR are the handshaking signals42).The MSP430 family operates in _________ mode Synchronous Asynchronous Both a and b None of the above HintThe MSP430 family operates in both synchronous and asynchronous mode43). What is the standard form of SCSR? Serial Communication Serial Register Serial Communication Status Register Serial Communication Register None of the above HintThe standard form of SCSR is Serial Communication Status Register44). The speed of the UART is ________ compare to USART Less High Very high None of the above HintThe speed of the UART is less compare to USART45). Which one of the following uses data signal for its functioning? UART USART Both a and b None of the above HintUART uses data signals for its functioning46). In which one of the following the data is transmitted in the form of bytes? UART USART Both a and b None of the above HintIn UART the data is transmitted in the form of bytes47). What is the standard form of UDR? UART Data Register USART Data Register USART Control Register None of the above HintThe standard form of UDR is UART Data Register48). Which one of the following is an SPI register? SPDR SPCR SPSR All of the above HintThe SPDR, SPCR, SPSR are the SPI registers49). The transmitter type of LIN is ____________ Synchronous Asynchronous Both a and b None of the above HintThe transmitter type of LIN is asynchronous50). The data rate of a UART is __________ 10Kbps 20Kbps 40Kbps 50Kbps HintThe data rate of a UART is 20KbpsUART Interview Questions and Answers51). The data rate of an SPI is __________ 10Mbps 25Mbps 40Mbps 50Kbps HintThe data rate of an SPI is 25Mbps52). Which one of the following scalability is low? UART SPI I2C None of the above HintIn UART the scalability is low53). What is the standard form of USR? UART Serial Register UART Status Register USART Simple Register None of the above HintThe standard form of USR is UART Status Register54). The transmitter type of SPI is __________ Synchronous Asynchronous Both a and b None of the above HintThe transmitter type of SPI is synchronous55). The data rate of I2C is ___________ 1Mbps 2Mbps 3Mbps 4Mbps HintThe data rate of I2C is 1Mbps56). Which one of the following scalability is high? I2C UART SPI None of the above HintThe I2C scalability is high compare to UART and SPI57). What is the standard form of UBRR? UART Baud Rate Register USART Baud Rate Register USART Baud Register None of the above HintThe standard form of UBRR is UART Baud Rate Register58). The maximum speed of a UART is ___________ 115Kbps 1Kbps 115.2Kbps 1.2Kbps HintThe maximum speed of a UART is 115.2Kbps59). The maximum speed of an SPI is ___________ 115Kbps 4Mbps 115.2Kbps 1.2Kbps HintThe maximum speed of an SPI is 4Mbps60). What is the standard form of UCR? UART Control Register USART Common Register USART Control Register None of the above HintThe standard form of UCR is UART Control Register61). The transmitter type of I2C is _______ Synchronous Asynchronous Both a and b None of the above HintThe transmitter type of I2C is synchronous62). The maximum speed of I2C is ___________ 15Kbps 4Mbps 115.2Kbps 1Mbps HintThe maximum speed of I2C is 1Mbps63). The maximum distance of a UART is ___________ 10m 12m 15m 29m HintThe maximum distance of a UART is 15m64). In a UART, the maximum possible number of devices in a bus is ___________ Two Unlimited Four Eight HintIn a UART, the maximum possible number of devices in a bus is two65). The associated protocol for serial interface RS-422 is ___________ UART I2C SPI None of the above HintThe associated protocol for serial interface RS-422 is UART66). The master unit is ______ in UART Variable Fixed Variable or fixed None of the above HintThe master unit is variable in UART 67). The maximum speed of RS-485 is ________ 15Kbps 4Mbps 115.2Kbps 1Mbps HintThe maximum speed of RS-485 is 115.2Kbps68). The maximum distance of SPI is ___________ 0.1m 12m 15m 29m HintThe maximum distance of SPI is 0.1m69). In SPI, the maximum possible number of devices in a bus is ___________ Unlimited Two Eight Several HintIn SPI, the maximum possible number of devices in a bus is virtually unlimited70). The master unit is ______ in USB 2.0 Variable Fixed Variable or fixed None of the above HintThe master unit is fixed in USB 2.071). The speed of USB is ______ 12M bit /sec 1M bit/sec 2M bytes/sec 4M bytes/sec HintThe speed of USB is 12M bit/sec72). The speed of SCSI is ______ 160M bytes/sec 1M bytes/sec 2M bytes/sec 4M bytes/sec HintThe speed of SCSI is 160M bytes/sec73). The maximum distance of I2C is ____________ 1m 2m 0.5m 12m HintThe maximum distance of I2C is 0.5m74). In I2C, the maximum possible number of devices in a bus is _________ 6 4 16 127 HintIn I2C, the maximum possible number of devices in a bus is 12775). The maximum throughput of RS 232 is _____________ 20KB/sec 2KB/sec 28.8KB/sec 10KB/sec HintThe maximum throughput of RS 232 is 28.8KB/sec76). The product availability of RS-232 is _____________ >500 <1000 >10,000 None of the above HintThe product availability of RS-232 is greater than 10,00077). The maximum distance of RS-485 is _________ 1.2km 15km 9km 10km HintThe maximum distance of RS-485 is 1.2km78). The maximum throughput of an Ethernet is _____________ 20KB/sec 125MB/sec 28.8KB/sec 10KB/sec HintThe maximum throughput of an Ethernet is 125MB/sec79). The maximum cable length of RS-232 is ___________ 1.2km 1.5km 9km 10km HintThe maximum cable length of RS-232 is 1.5km80). The maximum cable length of USB is ______ 1.2km 1.5km 9km 30km HintThe maximum cable length of USB is 30kmUART MCQ's for Exams81). What is the standard form of PCON? Power Control Power Control Receiver Power Control Register None of the above HintThe standard form of PCON is Power Control Register82). How many lines does I2C use between multiple slaves and multiple masters? One Two Three Four HintThe I2C uses two lines between multiple slaves and multiple masters83). What is the standard form of UARTFR? UART Flag Register USART Flag Register UART Register None of the above HintThe standard form of UARTFR is UART Flag Register84). Which one of the following is a write-only register? FCR IIR Both a and b None of the above HintThe FCR is a write-only register85). The UART transmitter consists of ___________ FIFO module Shift register Hold register All of the above HintThe UART transmitter consists of a FIFO module, shift and hold registers Read more about Shift Registers86). An UART used for _______ access Mainframe Internet Both a and b None of the above HintAn UART used for both mainframe and internet access87). What is the standard form of MCR? Modem Control Register Modem Control Receiver Modem Common Register None of the above HintThe standard form of MCR is Modem Control Register88). __________ are the revision identification registers REVID1 REVID2 Both a and b None of the above HintThe REVID1 and REVID2 are the revision identification registers89). What is the standard form of MDR? Modem Definition Register Mode Definition Receiver Module Data Register None of the above HintThe standard form of MDR is Modem Definition Register90). Which register contains the data to be transmitted? RBR THR FCR None of the above HintThe THR register contains the data to be transmitted91). Which register contains the data which is recently received? RBR THR FCR None of the above HintThe RBR register contains the data which is recently received92). Which register controls the universal asynchronous receiver transmitter frame formatting? RBR THR FCR LCR HintThe LCR register controls the universal asynchronous receiver transmitter frame formatting93). What is the standard form of MSR? Modem Status Register Mode Simple Receiver Module Data Register None of the above HintThe standard form of MSR is Modem Status Register94). Which register is used to disable/enable the transmission? TER THR FCR LCR HintThe TER register is used to disable/enable the transmission95). Which one of the following registers is a least significant byte of a universal asynchronous receiver transmitter baud rate generator value? DLL DLM Both a and b None of the above HintThe DLL register is a least significant byte of a universal asynchronous receiver transmitter baud rate generator value96). Which one of the following registers is a most significant byte of a universal asynchronous receiver transmitter baud rate generator value? DLL DLM Both a and b None of the above HintThe DLM register is a most significant byte of a universal asynchronous receiver transmitter baud rate generator value97). What is the standard form of UDRE? UART Data Register Empty UART Data Register USART Data Register Empty None of the above HintThe standard form of UDRE is UART Data Register Empty98). What are the applications of a UART? Bluetooth modules GPS units Microcontrollers All of the above HintThe Bluetooth modules, GPS units, microcontrollers, etc are the applications of a UART99). What is the standard form of DUDRE? Dual UART Data Register Empty Digital UART Data Register Empty Data UART Data Register Empty None of the above HintThe standard form of DUDRE is Dual UART Data Register Empty, it combines two UART’s into a one chip100).The UART 16550A has ____________FIFO buffers 2-byte 4-byte 8-byte 16-byte HintThe UART 16550A has 16-byte FIFO buffers Time is Up! Time's up
