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. 1). How many wires does UART use?OneTwoThreeFourHintUART uses two wires between transmitter and receiver 2). The UART frame consists of ___________ bitsDataStart/stopParityAll of the aboveHintThe UART frame consists of data, start/stop, and parity bits 3). Which bit is used for error detection?DataStart/stopParityAll of the aboveHintThe parity bit is used for error detection 4). In which parity the number of 1’s must be even?EvenOddBoth a and bNone of the aboveHintIn even parity the number of 1’s must be even 5). ____________ are the UART registersControl and statusReceiveTransmitAll of the aboveHintThe control, status, transmit and receive registers are the UART registers 6). Which one of the following registers contains settings for the UART?ControlReceiveTransmitAll of the aboveHintThe control register contains settings for the UART 7). Which one of the following registers contains information about the UART state or condition?ControlReceiveTransmitStatusHintThe status register contains information about the UART state or condition 8). The universal asynchronous receiver transmitter can be _____________SimplexFull-duplexHalf-duplexAll of the aboveHintThe universal asynchronous receiver transmitter can be simplex, full-duplex, and half-duplex 9). In which parity the number of 1’s must be odd?EvenOddBoth a and bNone of the aboveHintIn odd parity, the number of 1’s must be odd 10). The number of bits sent every second is known as ________ rateBitByteBaudNone of the aboveHintThe number of bits sent every second is known as the bit rate 11). The number of symbols sent every second is known as ________ rateBitByteBaudNone of the aboveHintThe number of symbols sent every second is known as the baud rate 12). Which one is a type of UART flag?TDRERSRRDRNone of the aboveHintThe TDRE is a type of UART flag 13). Which one is a type of UART register?TDRERSRSCSRNone of the aboveHintThe SCSR is a type of UART register 14). What is the standard form of TDRE?Transmit Data Register EmptyTransmit Data Rate EmptyTransmit Data Register EnableNone of the aboveHintThe standard form of TDRE is Transmit Data Register Empty, it is one type of UART flag 15). ____________ is an example for data communication equipmentModemComputerTerminalNone of the aboveHintThe modem is an example of data communication equipment 16). What is the standard form of DTE?Data Transfer EquipmentData Terminal EquipmentData Transmit EquipmentNone of the aboveHintThe standard form of DTE is Data Terminal Equipment 17). What is the standard form of RDRF?Receiver Data Register FullReceiver Data Rate FullRegister Data Receiver FullNone of the aboveHintThe standard form of RDRF is Receiver Data Register Full 18). ____________ is an example for data terminal equipmentTerminalComputerBoth a and bNone of the aboveHintThe computer and terminal both are the examples for data terminal equipment 19). What is the standard form of DCE?Data Communication EquipmentData Common EquipmentData Control Unit EquipmentNone of the aboveHintThe standard form of DCE is Data Communication Equipment 20). What are the advantages of UART?Uses only two wiresWidely used methodClock signal is not necessaryAll of the aboveHintThe UART is a widely used method, it uses only two wires, and the clock signal is not necessary for UART 21). What is the standard form of RDR?Receiver Data RegisterRegister Data ReceiverReceiver Shift RegisterNone of the aboveHintThe standard form of RDR is Receiver Data Register, it is a type of UART register 22). What are the disadvantages of UART?Doesn’t support multiple slaveData frame size is limited to a 9 bits maxBoth a and bNone of the aboveHintThe disadvantages of a UART are it doesn’t support multiple slaves, and the data frame size is limited to a 9 bits max 23). What is the function of the UARTn_TXD signal?Serial data transmit-receiveClear to send handshaking signalBoth a and bNone of the aboveHintThe function of the UARTn_TXD signal is serial data transmit-receive 24). The transmitter section of an UART consists of __________Transmitter shift registerTransmitter hold registerBoth a and bNone of the aboveHintThe transmitter section of a UART consists of transmitter shift register and transmitter hold register 25). What is the standard form of RSR?Receiver Data RegisterRegister Shift ReceiverReceive Shift RegisterNone of the aboveHintThe standard form of RSR is Receive Shift RegisterUART MCQ's with Answers 26). What is the function of UARTn_RTX?Serial data receiveClear to send handshaking signalBoth a and bNone of the aboveHintThe function of UARTn_RTX is Serial data receive 27). Which one of the following was used to enable or disable the interrupt request?IERIIRBoth a and bNone of the aboveHintThe IER is used to enable or disable the interrupt request 28). Which one of the following is a write-only register?FIFO control registerInterrupt identification registerBoth a and bNone of the aboveHintThe FIFO control register is a write-only register 29). What is the standard form of TDR?Transport Data RegisterTransmit Data RegisterTransmit Data ReceiverNone of the aboveHintThe standard form of TDR is Transmit Data Register 30). Which one of the following is a divisor latch?DLHDLLBoth a and bNone of the aboveHintBoth DLH and DLL are the divisor latches 31). The baud rate of 8-bit UART is ___________1200bps1500bps9600bpsNone of the aboveHintThe baud rate of 8-bit UART is 9600bps 32). In 8-bit UART 1 byte is equal to ____________ bitsTwoFourEightSixteenHintIn 8-bit UART 1 byte is equal to eight bits 33). The bits transferred per second is _______ in 8-bit UART1,0005,0988,1926,789HintThe bits transferred per second is 8,192 in 8-bit UART 34). The data in a UART is detected by __________CounterClockBoth a and bNone of the aboveHintThe data in a UART is detected by clock Read more about UART 35). What is the standard form of TSR?Transmit Shift RegisterTransport Status RegisterTransmit Status ReceiverNone of the aboveHintThe standard form of TSR is Transmit Shift Register 36). The baud rate of 16 bit UART is ___________1200bps1500bps9600bpsNone of the aboveHintThe baud rate of 16 bit UART is 9600bps 37). In 16-bit UART 1 byte is equal to ____________ bitsTwoFourEightSixteenHintIn 16-bit UART 1 byte is equal to 16 bits 38). The bits transferred per second is ______ in 16 bit UART12,89815,08996,23016,384HintThe bits transferred per second is 16,384 in 16 bit UART 39). Which register does UART contain?ClockShiftBoth a and bNone of the aboveHintA universal asynchronous receiver transmitter contains a shift register 40). What is the standard form of SCCR?Serial Communication Control RegisterSerial Communication Common RegisterSerial Communication RegisterNone of the aboveHintThe standard form of SCCR is Serial Communication Control Register, it is a type of UART register 41). _________ are the handshaking signalsRI, DCD, CTSDSR, RTSDTRAll of the aboveHintThe RI, DCD, CTS, DSR, RTS, DTR are the handshaking signals 42).The MSP430 family operates in _________ modeSynchronousAsynchronousBoth a and bNone of the aboveHintThe MSP430 family operates in both synchronous and asynchronous mode 43). What is the standard form of SCSR?Serial Communication Serial RegisterSerial Communication Status RegisterSerial Communication RegisterNone of the aboveHintThe standard form of SCSR is Serial Communication Status Register 44). The speed of the UART is ________ compare to USARTLessHighVery highNone of the aboveHintThe speed of the UART is less compare to USART 45). Which one of the following uses data signal for its functioning?UARTUSARTBoth a and bNone of the aboveHintUART uses data signals for its functioning 46). In which one of the following the data is transmitted in the form of bytes?UARTUSARTBoth a and bNone of the aboveHintIn UART the data is transmitted in the form of bytes 47). What is the standard form of UDR?UART Data RegisterUSART Data RegisterUSART Control RegisterNone of the aboveHintThe standard form of UDR is UART Data Register 48). Which one of the following is an SPI register?SPDRSPCRSPSRAll of the aboveHintThe SPDR, SPCR, SPSR are the SPI registers 49). The transmitter type of LIN is ____________SynchronousAsynchronousBoth a and bNone of the aboveHintThe transmitter type of LIN is asynchronous 50). The data rate of a UART is __________10Kbps20Kbps40Kbps50KbpsHintThe data rate of a UART is 20KbpsUART Interview Questions and Answers 51). The data rate of an SPI is __________10Mbps25Mbps40Mbps50KbpsHintThe data rate of an SPI is 25Mbps 52). Which one of the following scalability is low?UARTSPII2CNone of the aboveHintIn UART the scalability is low 53). What is the standard form of USR?UART Serial RegisterUART Status RegisterUSART Simple RegisterNone of the aboveHintThe standard form of USR is UART Status Register 54). The transmitter type of SPI is __________SynchronousAsynchronousBoth a and bNone of the aboveHintThe transmitter type of SPI is synchronous 55). The data rate of I2C is ___________1Mbps2Mbps3Mbps4MbpsHintThe data rate of I2C is 1Mbps 56). Which one of the following scalability is high?I2CUARTSPINone of the aboveHintThe I2C scalability is high compare to UART and SPI 57). What is the standard form of UBRR?UART Baud Rate RegisterUSART Baud Rate RegisterUSART Baud RegisterNone of the aboveHintThe standard form of UBRR is UART Baud Rate Register 58). The maximum speed of a UART is ___________115Kbps1Kbps115.2Kbps1.2KbpsHintThe maximum speed of a UART is 115.2Kbps 59). The maximum speed of an SPI is ___________115Kbps4Mbps115.2Kbps1.2KbpsHintThe maximum speed of an SPI is 4Mbps 60). What is the standard form of UCR?UART Control RegisterUSART Common RegisterUSART Control RegisterNone of the aboveHintThe standard form of UCR is UART Control Register 61). The transmitter type of I2C is _______SynchronousAsynchronousBoth a and bNone of the aboveHintThe transmitter type of I2C is synchronous 62). The maximum speed of I2C is ___________15Kbps4Mbps115.2Kbps1MbpsHintThe maximum speed of I2C is 1Mbps 63). The maximum distance of a UART is ___________10m12m15m29mHintThe maximum distance of a UART is 15m 64). In a UART, the maximum possible number of devices in a bus is ___________TwoUnlimitedFourEightHintIn a UART, the maximum possible number of devices in a bus is two 65). The associated protocol for serial interface RS-422 is ___________UARTI2CSPINone of the aboveHintThe associated protocol for serial interface RS-422 is UART 66). The master unit is ______ in UARTVariableFixedVariable or fixedNone of the aboveHintThe master unit is variable in UART 67). The maximum speed of RS-485 is ________15Kbps4Mbps115.2Kbps1MbpsHintThe maximum speed of RS-485 is 115.2Kbps 68). The maximum distance of SPI is ___________0.1m12m15m29mHintThe maximum distance of SPI is 0.1m 69). In SPI, the maximum possible number of devices in a bus is ___________UnlimitedTwoEightSeveralHintIn SPI, the maximum possible number of devices in a bus is virtually unlimited 70). The master unit is ______ in USB 2.0VariableFixedVariable or fixedNone of the aboveHintThe master unit is fixed in USB 2.0 71). The speed of USB is ______12M bit /sec1M bit/sec2M bytes/sec4M bytes/secHintThe speed of USB is 12M bit/sec 72). The speed of SCSI is ______160M bytes/sec1M bytes/sec2M bytes/sec4M bytes/secHintThe speed of SCSI is 160M bytes/sec 73). The maximum distance of I2C is ____________1m2m0.5m12mHintThe maximum distance of I2C is 0.5m 74). In I2C, the maximum possible number of devices in a bus is _________6416127HintIn I2C, the maximum possible number of devices in a bus is 127 75). The maximum throughput of RS 232 is _____________20KB/sec2KB/sec28.8KB/sec10KB/secHintThe maximum throughput of RS 232 is 28.8KB/sec 76). The product availability of RS-232 is _____________>500<1000>10,000None of the aboveHintThe product availability of RS-232 is greater than 10,000 77). The maximum distance of RS-485 is _________1.2km15km9km10kmHintThe maximum distance of RS-485 is 1.2km 78). The maximum throughput of an Ethernet is _____________20KB/sec125MB/sec28.8KB/sec10KB/secHintThe maximum throughput of an Ethernet is 125MB/sec 79). The maximum cable length of RS-232 is ___________1.2km1.5km9km10kmHintThe maximum cable length of RS-232 is 1.5km 80). The maximum cable length of USB is ______1.2km1.5km9km30kmHintThe maximum cable length of USB is 30kmUART MCQ's for Exams 81). What is the standard form of PCON?Power ControlPower Control ReceiverPower Control RegisterNone of the aboveHintThe standard form of PCON is Power Control Register 82). How many lines does I2C use between multiple slaves and multiple masters?OneTwoThreeFourHintThe I2C uses two lines between multiple slaves and multiple masters 83). What is the standard form of UARTFR?UART Flag RegisterUSART Flag RegisterUART RegisterNone of the aboveHintThe standard form of UARTFR is UART Flag Register 84). Which one of the following is a write-only register?FCRIIRBoth a and bNone of the aboveHintThe FCR is a write-only register 85). The UART transmitter consists of ___________FIFO moduleShift registerHold registerAll of the aboveHintThe UART transmitter consists of a FIFO module, shift and hold registers Read more about Shift Registers 86). An UART used for _______ accessMainframeInternetBoth a and bNone of the aboveHintAn UART used for both mainframe and internet access 87). What is the standard form of MCR?Modem Control RegisterModem Control ReceiverModem Common RegisterNone of the aboveHintThe standard form of MCR is Modem Control Register 88). __________ are the revision identification registersREVID1REVID2Both a and bNone of the aboveHintThe REVID1 and REVID2 are the revision identification registers 89). What is the standard form of MDR?Modem Definition RegisterMode Definition ReceiverModule Data RegisterNone of the aboveHintThe standard form of MDR is Modem Definition Register 90). Which register contains the data to be transmitted?RBRTHRFCRNone of the aboveHintThe THR register contains the data to be transmitted 91). Which register contains the data which is recently received?RBRTHRFCRNone of the aboveHintThe RBR register contains the data which is recently received 92). Which register controls the universal asynchronous receiver transmitter frame formatting?RBRTHRFCRLCRHintThe LCR register controls the universal asynchronous receiver transmitter frame formatting 93). What is the standard form of MSR?Modem Status RegisterMode Simple ReceiverModule Data RegisterNone of the aboveHintThe standard form of MSR is Modem Status Register 94). Which register is used to disable/enable the transmission?TERTHRFCRLCRHintThe TER register is used to disable/enable the transmission 95). Which one of the following registers is a least significant byte of a universal asynchronous receiver transmitter baud rate generator value?DLLDLMBoth a and bNone of the aboveHintThe DLL register is a least significant byte of a universal asynchronous receiver transmitter baud rate generator value 96). Which one of the following registers is a most significant byte of a universal asynchronous receiver transmitter baud rate generator value?DLLDLMBoth a and bNone of the aboveHintThe DLM register is a most significant byte of a universal asynchronous receiver transmitter baud rate generator value 97). What is the standard form of UDRE?UART Data Register EmptyUART Data RegisterUSART Data Register EmptyNone of the aboveHintThe standard form of UDRE is UART Data Register Empty 98). What are the applications of a UART?Bluetooth modulesGPS unitsMicrocontrollersAll of the aboveHintThe Bluetooth modules, GPS units, microcontrollers, etc are the applications of a UART 99). What is the standard form of DUDRE?Dual UART Data Register EmptyDigital UART Data Register EmptyData UART Data Register EmptyNone of the aboveHintThe standard form of DUDRE is Dual UART Data Register Empty, it combines two UART’s into a one chip 100).The UART 16550A has ____________FIFO buffers2-byte4-byte8-byte16-byteHintThe UART 16550A has 16-byte FIFO buffers Time is Up! Time's up
