The 8051 Microcontroller

Q1: The number of data registers is:

A 8

B 16

C 32

D 64

Q2:
This program code will be executed continuously:
STAT: MOV A, #01H
 JNZ STAT

A True

B False

Q3: 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

Q4: The 8051 has ________ 16-bit counter/timers.

A 1

B 2

C 3

D 4

Q5: Both registers TL0 and TL1 are needed to start Timer 0.

A True

B False

Q6: The start-conversion on the ADC0804 is done by using the:

A

B CS line

C INTR line

D V ref/2 line

Q7: 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

Q8: Device pins XTAL1 and XTAL2 for the 8051 are used for connections to an external oscillator or crystal.

A True

B False

Q9: 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

Q10: 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.

Q11:
This statement will set the address of the bit to 1 (8051 Micro-controller):
SETB 01H

A True

B False

Q12: 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

Q13: 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

Q14: The special function registers can be referred to by their hex addresses or by their register names.

A True

B False

Q15: The microcontroller is useful in systems that have nonvariable programs for dedicated applications.

A True

B False

Q16:
.
The following command will rotate the 8 bits of the accumulator one position to the left:
RL A

A True

B False

Q17: The following command will copy the accumulator to the location whose address is 23H:
MOV 23H,A

A True

B False

Q18: The total amount of external code memory that can be interfaced to the 8051 is:

A 32K

B 64K

C 128K

D 256K

Q19: 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

Q20: To interface external EPROM memory for applications, it is necessary to demultiplex the address/data lines of the 8051.

A True

B False

Q21: The special function registers are maintained in the next 128 locations after the general-purpose data storage and stack.

A True

B False

Q22: The contents of the accumulator after this operation
MOV A,#0BH
ANL A,#2CH
will be

A 11010111

B 11011010

C 00001000

D 00101000

Q23: A HIGH on which pin resets the 8051 microcontroller?

A RESET

B RST

C PSEN

D RSET

Q24: 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

Q25: 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

Q26: The designs of a centigrade thermometer and a PWM speed-control circuit can be implemented by the 8051.

A True

B False

Q27: The microcontroller is useful in systems that have nonvariable programs for dedicated applications.

A True

B False

Q28: 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

Q29: The 8051 has ________ parallel I/O ports.

A 2

B 3

C 4

D 5

Q30: The last 96 locations in the internal data memory are reserved for general-purpose data storage and stack.

A True

B False

Q31: The total external data memory that can be interfaced to the 8051 is:

A 32K

B 64K

C 128K

D 256K

Q32: The ADC0804 has ________ resolution.

A 4-bit

B 8-bit

C 16-bit

D 32-bit

Q33: This program code will be executed once:
STAT: MOV A, #01H
  JNZ STAT

A True

B False

Q34: 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

Q35: Microcontrollers often have:

A CPUs

B RAM

C ROM

D all of the above

Q36: The internal RAM memory of the 8051 is:

A 32 bytes

B 64 bytes

C 128 bytes

D 256 bytes

Q37: A label is used to name a single line of code.

A True

B False

Q38: Data transfer from I/O to external data memory can only be done with the MOVX command.

A True

B False

Q39: 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

Q40: Bit-addressable memory locations are:

A 10H through 1FH

B 20H through 2FH

C 30H through 3FH

D 40H through 4FH

Q41: 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

Q42: The following program will cause the 8051 to be stuck in a loop:
LOOP: MOV A, #00H
  JNZ LOOP

A True

B False

Q43: When the 8051 is reset and the  line is HIGH, 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

Q44: 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

Q45: 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

Q46: The statement LCALL READ passes control to the line labelled READ.

A True

B False

Q47: 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

Q48: Data transfer from I/O to external data memory can only be done with the MOV command.

A True

B False

Q49: 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

Q50: The 8051 can handle ________ interrupt sources.

A 3

B 4

C 5

D 6

Q51: An alternate function of port pin P3.4 in the 8051 is:

A Timer 0

B Timer 1

C interrupt 0

D interrupt 1

Q52: 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

Q53: 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

Q54: 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

Q55: 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


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