The 8051 Microcontroller MCQs : This section focuses on the "The 8051 Microcontroller". These Multiple Choice Questions (MCQs) should be practiced to improve the The 8051 Microcontroller skills required for various interviews (campus interview, walk-in interview, company interview), placement, entrance exam and other competitive examinations.
Question 1
The contents of the accumulator after this operation MOV A,#0BH ANL A,#2CH will be
A. 11010111
B. 11011010
C. 1000
D. 101000
Question 2
The following command will copy the accumulator to the location whose address is 23H: MOV 23H,A
A. TRUE
B. FALSE
Question 3
The total amount of external code memory that can be interfaced to the 8051 is:
A. 32K
B. 64K
C. 128K
D. 256K
Question 4
Which of the following commands will move the number 27H into the accumulator?
A. MOV A, P27
B. MOV A, #27H
C. MOV A, 27H
D. MOV A, @27
Question 5
The contents of the accumulator after this operation MOV A,#2BH ORL A,00H will be:
A. 1B H
B. 2B H
C. 3B H
D. 4B H
Question 6
This program code will be executed once: STAT: MOV A, #01H JNZ STAT
A. TRUE
B. FALSE
Question 7
The microcontroller is useful in systems that have nonvariable programs for dedicated applications.
A. TRUE
B. FALSE
Question 8
The 8-bit address bus allows access to an address range of:
A. 0000 to FFFFH
B. 000 to FFFH
C. 00 to FFH
D. 0 to FH
Question 9
Data transfer from I/O to external data memory can only be done with the MOV command.
A. TRUE
B. FALSE
Question 10
This statement will set the address of the bit to 1 (8051 Micro-controller): SETB 01H
A. TRUE
B. FALSE
Question 11
What is the difference between the 8031 and the 8051?
A. The 8031 has no interrupts.
B. The 8031 is ROM-less.
C. The 8051 is ROM-less.
D. The 8051 has 64 bytes more memory.
Question 12
A label is used to name a single line of code.
A. TRUE
B. FALSE
Question 13
The 8051 has ________ 16-bit counter/timers.
A. 1
B. 2
C. 3
D. 4
Question 14
An alternate function of port pin P3.1 in the 8051 is:
A. serial port input
B. serial port output
C. memory write strobe
D. memory read strobe
Question 15
Which of the following commands will copy the contents of location 4H to the accumulator?
A. MOV A, 04H
B. MOV A, L4
C. MOV L4, A
D. MOV 04H, A
Question 16
Which of the following statements will add the accumulator and register 3?
A. ADD @R3, @A
B. ADD @A, R3
C. ADD R3, A
D. ADD A, R3
Question 17
Which of the following instructions will move the contents of the accumulator to register 6?
A. MOV 6R, A
B. MOV R6, A
C. MOV A, 6R
D. MOV A, R6
Question 18
When the 8051 is reset and the EA line is LOW, the program counter points to the first program instruction in the:
A. internal code memory
B. external code memory
C. internal data memory
D. external data memory
Question 19
The ADC0804 has ________ resolution.
A. 4-bit
B. 8-bit
C. 16-bit
D. 32-bit
Question 20
An alternate function of port pin P3.0 (RXD) in the 8051 is:
A. serial port input
B. serial port output
C. memory write strobe
D. memory read strobe
Question 21
Which of the following instructions will load the value 35H into the high byte of timer 0?
A. MOV TH0, #35H
B. MOV TH0, 35H
C. MOV T0, #35H
D. MOV T0, 35H
Question 22
The 8051 has ________ parallel I/O ports.
A. 2
B. 3
C. 4
D. 5
Question 23
The designs of a centigrade thermometer and a PWM speed-control circuit can be implemented by the 8051.
A. TRUE
B. FALSE
Question 24
The I/O port that does not have a dual-purpose role is:
A. port 0
B. port 1
C. port 2
D. port 3
Question 25
Device pins XTAL1 and XTAL2 for the 8051 are used for connections to an external oscillator or crystal.
A. TRUE
B. FALSE
Question 26
This program code will read data from port 0 and write it to port 2, and it will stop looping when bit 3 of port 2 is set: STAT: MOV A, PO MOV P2,A JNB P2.3, STAT
A. TRUE
B. FALSE
Question 27
MOV A, @ R1 will:
A. copy R1 to the accumulator
B. copy the accumulator to R1
C. copy the contents of memory whose address is in R1 to the accumulator
D. copy the accumulator to the contents of memory whose address is in R1
Question 28
Which of the following instructions will move the contents of register 3 to the accumulator?
A. MOV 3R, A
B. MOV R3, A
C. MOV A, R3
D. MOV A, 3R
Question 29
Which of the following commands will move the value at port 3 to register 2?
A. MOV P2, R3
B. MOV R3, P2
C. MOV 3P, R2
D. MOV R2, P3
Question 30
To interface external EPROM memory for applications, it is necessary to demultiplex the address/data lines of the 8051.
A. TRUE
B. FALSE
Question 31
The last 96 locations in the internal data memory are reserved for general-purpose data storage and stack.
A. TRUE
B. FALSE
Question 32
Microcontrollers often have:
A. CPUs
B. RAM
C. ROM
D. all of the above
Question 33
The internal RAM memory of the 8051 is:
A. 32 bytes
B. 64 bytes
C. 128 bytes
D. 256 bytes
Question 34
An alternate function of port pin P3.4 in the 8051 is:
A. Timer 0
B. Timer 1
C. interrupt 0
D. interrupt 1
Question 35
The following program will cause the 8051 to be stuck in a loop: LOOP: MOV A, #00H JNZ LOOP
A. TRUE
B. FALSE
Question 36
Data transfer from I/O to external data memory can only be done with the MOVX command.
A. TRUE
B. FALSE
Question 37
Which of the following commands will copy the contents of RAM whose address is in register 0 to port 1?
A. MOV @ P1, R0
B. MOV @ R0, P1
C. MOV P1, @ R0
D. MOV P1, R0
Question 38
The address space of the 8051 is divided into four distinct areas: internal data, external data, internal code, and external code.
A. TRUE
B. FALSE
Question 39
The special function registers can be referred to by their hex addresses or by their register names.
A. TRUE
B. FALSE
Question 40
This program code will be executed continuously: STAT: MOV A, #01H JNZ STAT
A. TRUE
B. FALSE
Question 41
The following command will rotate the 8 bits of the accumulator one position to the left: RL A
A. TRUE
B. FALSE
Question 42
The total external data memory that can be interfaced to the 8051 is:
A. 32K
B. 64K
C. 128K
D. 256K
Question 43
The 8051 can handle ________ interrupt sources.
A. 3
B. 4
C. 5
D. 6
Question 44
Both registers TL0 and TL1 are needed to start Timer 0.
A. TRUE
B. FALSE
Question 45
The statement LCALL READ passes control to the line labelled READ.
A. TRUE
B. FALSE
Question 46
The I/O ports that are used as address and data for external memory are:
A. ports 1 and 2
B. ports 1 and 3
C. ports 0 and 2
D. ports 0 and 3
Question 47
The special function registers are maintained in the next 128 locations after the general-purpose data storage and stack.
A. TRUE
B. FALSE
Question 48
The number of data registers is:
A. 8
B. 16
C. 32
D. 64
Question 49
The following program will receive data from port 1, determine whether bit 2 is high, and then send the number FFH to port 3: READ: MOV A,P1 ANL A,#2H CJNE A,#02H,READ MOV P3,#FFH
A. TRUE
B. FALSE
Question 50
Bit-addressable memory locations are:
A. 10H through 1FH
B. 20H through 2FH
C. 30H through 3FH
D. 40H through 4FH
Question 51
A HIGH on which pin resets the 8051 microcontroller?
A. RESET
B. RST
C. PSEN
D. RSET