A directory of Objective Type Questions covering all the Computer Science subjects. Here you can access and discuss Multiple choice questions and answers for various compitative exams and interviews.

151. In 8085 microprocessor, what is the output of following program?

LDA 8000H
MVI B, 30H
ADD B
STA 8001H
a. Read a number from input port and store it in memory
b. Read a number from input device with address 8000H and store it in memory at location 8001H
c. Read a number from memory at location 8000H and store it in memory location 8001H
d. Load A with data from input device with address 8000H and display it on the output device with address 8001H
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Answer: (d).Load A with data from input device with address 8000H and display it on the output device with address 8001H

152. The Boolean function with the following Karnaugh map is :
a. (A + C).D + B
b. (A + B).C + D
c. (A + D).C + B
d. (A + C).B + D
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Answer: (a).(A + C).D + B

153. The Octal equivalent of the binary number 1011101011 is:
a. 7353
b. 1353
c. 5651
d. 5657
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Answer: (b).1353

154. The output of the following combinational circuit is F. The value of F is :
a. P1+P2’P3
b. P1+P2’P3’
c. P1+P2P3’
d. P1’+P2P3
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Answer: (b).P1+P2’P3’

155. In 8085 microprocessor which of the following flag(s) is (are) affected by an arithmetic operation?
a. AC flag Only
b. CY flag Only
c. Z flag Only
d. AC, CY, Z flags
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Answer: (d).AC, CY, Z flags

156. In 8085 microprocessor the address bus is of .................... bits.
a. 4
b. 8
c. 16
d. 32
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Answer: (c).16

157. In the architecture of 8085 microprocessor match the following:

List - I
(a) Processing unit
(b) Instruction unit
(c) Storage and Interface unit

List - II
(i) Interrupt
(ii) General purpose Register
(iii) ALU
(iv) Timing and Control
Code :
(a) (b) (c)
a. (iv) (i) (ii)
b. (iii) (iv) (ii)
c. (ii) (iii) (i)
d. (i) (ii) (iv)
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Answer: (b).(iii) (iv) (ii)

158. Which of the following addressing mode is best suited to access elements of an array of contiguous memory locations?
a. Indexed addressing mode
b. Base Register addressing mode
c. Relative address mode
d. Displacement mode
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Answer: (a).Indexed addressing mode

159. Which of the following is correct statement?
a. In memory - mapped I/O, the CPU can manipulate I/O data residing in interface registers that are not used to manipulate memory words.
b. The isolated I/O method isolates memory and I/O addresses so that memory address range is not affected by interface address assignment.
c. In asynchronous serial transfer of data the two units share a common clock.
d. In synchronous serial transmission of data the two units have different clocks.
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Answer: (b).The isolated I/O method isolates memory and I/O addresses so that memory address range is not affected by interface address assignment.

160. A micro-instruction format has micro-ops field which is divided into three subfields F1, F2, F3 each having seven distinct micro-operations, condition field CD for four status bits, branch field BR having four options used in conjunction with address field ADF. The address space is of 128 memory locations. The size of micro-instruction is:
a. 17 bits
b. 20 bits
c. 24 bits
d. 32 bits
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Answer: (b).20 bits