MP and MC interview Questions4

                                    UNIT-7

1.  The internal RAM memory of the 8051 is: A. 32 bytes B. 64 bytes C. 128 bytes D. 256 bytes Answer: Option C

2.The 8051 has ________ 16-bit counter/timers.

A.	1	B.	2
C.	3	D.	4

Answer: Option B

3.  The 8051 can handle ________ interrupt sources. A. 3 B. 4 C. 5 D. 6 Answer: Option C

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

A.	Timer 0
B.	Timer 1
C.	interrupt 0
D.	interrupt 1

Answer: Option A

   

5.  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 Answer: Option C

  6.Microcontrollers often have:

A.	CPUs
B.	RAM
C.	ROM
D.	all of the above

Answer: Option D

7.The 8051 has ________ parallel I/O ports.

A.	2	B.	3
C.	4	D.	5

Answer: Option C

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

A.	32K	B.	64K
C.	128K	D.	256K

Answer: Option B

9.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

Answer: Option C

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

A.
B.	CS line
C.	INTR line
D.	V ref/2 line

Answer: Option A

			11.The number of data registers is:
			A. 8 B. 16 C. 32 D. 64 Answer: Option C
12.			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 Answer: Option B 13.  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. Answer: Option B 14..  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 Answer: Option B
	15..  The microcontroller is useful in systems that have nonvariable programs for dedicated applications. A. True B. False            Answer: Option A  16.  The total amount of external code memory that can be interfaced to the 8051 is: A. 32K B. 64K C. 128K D. 256K Answer: Option B 17..  The ADC0804 has ________ resolution. A. 4-bit B. 8-bit C. 16-bit D. 32-bit Answer: Option B 18.  A HIGH on which pin resets the 8051 microcontroller? A. RESET B. RST C. PSEN D. RSET Answer: Option B 19.  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 Answer: Option B

      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

Answer: Option A

                              

UNIT-8

1. Which of the following instruction perform the move accumulator to external RAM of 16bit address?

a) MOV @ DPTR, A b) MOVX @ Ri, A

c) MOV A, @ Ri d) MOVX @ DPTR, A

2. Which of the following instruction perform jump indirect relative to DPTR

a) JMP A+DPTR b) JMP DPTR

c) JMP @A+DPTR d) SJMP A+DPTR

3. Which of the following instruction is wrong

a) INC DPTR b) MOV @DPTR, A

c) MOV A, @A+DPTR d) DEC DPTR

4. What instruction performs Compare immediate to indirect and jump if not equal.

a) CJNE A, #data, rel b) CJNE Rn, #data, rel

c) CJNE @ Ri, #data, rel d) CJNE A, data, rel

5. What is the Result of RR A instruction if accumulator contains 1000 0000.

a) 0000 0001 b) 0000 0000 c) 0100 0000 d) 0000 0010

6. MOV 45, #4FH

MOV R0, 45H

INC R0

MOV @R0, #30H

What is the location value of R0 and the content at that place?

a) 45H, 4F b) 50H, 30H c) 30H, 50H d) 50H, 45H

7. Which of the following is of type memory initialized Directive?

i) DS ii) SETiii) DW iv) DBIT

a) i, iii b) ii c) iii d) iv, ii

8. Which of the following is not a program linking directive

i) EXTRN ii) SEGMENT iii) NAME iv) PUBLIC v) USING

a) iv, v b) ii, iii c) i, iii d) ii, v

9. SP of 8051 is of ___ wide and it is loaded with the default value of ___ after reset.

a) 2 byte, 08H b) 8 bit, 07H c) 1 byte, 09H d) 8 bit, 06H

10. Which of the following instruction is used to set bit port directly?

a) SET P1.0 b) MOV P1.0, bit c) SETB P1.0 d) JB P1.0, bit

11. MOV A, #56H

      MOV R1, #50H

      MOV 50H, # 45H

      XCHD A, @R1

What is the result at A, R1?

a)      56H, 45H b) 45H, 50H c) 50H, 56H d) 45H, 56H

12. In 8051 an external interrupt 1 vector address is of ________ and causes of interrupt if ____.

a) 000BH, a high to low transition on pin INT1

b) 001BH, a low to high transition on pin INT1

c) 0013H, a high to low transition on pin INT1

d) 0023H, a low to high transition on pin INT1

13. Serial port vector address is of _______. And causes an interrupt when ________.

a) 0013H, either TI or RI flag is set

b) 0023H, either TI or RI flag is reset

c) 0013H, either TI or RI flag is reset

d) 0023H, either TI or RI flag is set

14. In serial communication modes, mode 1 the Baud rate =

a) BR=2^SMOD/32 * (Timer 0 over flow rate)

b) BR=2^SMOD/16 * (Timer 1 over flow rate)

c) BR=2^SMOD/16 * (Timer 0 over flow rate)

d) BR=2^SMOD/32 * (Timer 1 over flow rate)

15. In modes 2 and 3, if _____ bit of SCON bit is set will causes enable multiprocessor communication and is of ____ bit address.

a) SM1, 9EH b) TB8 , 9CH c) SM2 , 9DH d) SM0, 9FH

16. Interfacing LCD with 89C51 _____ data lines are used along with the _____ signals.

a) 6, RS, RW b) 5, RW, EN c) 8, RS, EN, RW d) 9, RS, EN, RW

17. Resolution of ADC is defined as

a)      1/ (2N – 1) b) 2^N-1c) 1/ (2^N-1) d) 2N-1

 18. In microcontroller and LCD interface which line will instruct the LCD that microcontroller is sending data?

a) DB0 b) RW c) EN d) RS

19. Which bit of TMOD will exactly configure timer / counter as a timer or counter.

i) TMOD.6 of C/T for timer 1 ii) TMOD.6 of C/T for timer 0

iii) TMOD.2 of C/T for timer 0 iv) TMOD.2 of C/T for timer 1

a) i, ii b) ii, ivc) i, iii d) iii, iv

20. Which of the following instruction is of logical instructions?

i) CPL A

ii) JC rel

iii) DA A

iv) ANL A, Rn

v) RR A

vi) CPL bit

a)      i, v b) v, iii, I c) iv, ii d) v, iii, ii