Digital Circuit and Microprocessor MCQs

Question 1

In 8085, the instruction register is part of the control unit. The contents of the instruction register are split into two nibbles. The upper nibble goes to the

Accepted Answer

controller sequence

Answer

memory address

Answer

source programme

Answer

micro-instruction

Question 2

The nmemonics used in writing a program is called

Accepted Answer

(e) object program

Answer

assembly language

Answer

fetch cycle micro-instruction

Answer

none of the above

Question 3

In micro-processors like 8080 and the 8085, the cycle may have from one to five machine cycle

Accepted Answer

instruction

Answer

micro-instruction

Answer

source program

Answer

fetch cycle

Question 4

A___ is used to isolatea bit ; it does this because the ANI sets all other bits to zero.

Accepted Answer

mask

Answer

subroutine

Answer

flag

Answer

label

Question 5

Match the following :Column I Column 11(a) Pop (i) to save data in the stock(b) Push(ii) to read data from the stack (c) Stack (iii) a portion of memory reserved for return addresses and data(d) Mask (iv) a byte used with an ANI instruction to blankout certain bits

Accepted Answer

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

Answer

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

Answer

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

Answer

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

Question 6

Vectored interrupt is an interrupt that takes the program to a vector location. TRAP vectors to 0024 H, RST 7.5 to 003 CH, RST 6.5 to 0034 H and

Accepted Answer

RST 5.5 to 002 CH

Answer

RST 5.5

Answer

RST 6.5

Answer

24 H to 48 H

Question 7

TRAP is where as RST 7.5, RST 6.5, RST 5.5 are

Accepted Answer

non-maskable, maskable

Answer

maskable, non-maskable

Answer

maskable, maskable

Answer

non-maskable, non-maskable

Question 8

Which interrupts are masked

Accepted Answer

6.5

Answer

5.5

Answer

7.5

Answer

none

Question 9

How many outputs are there in the output of a 10-bit D/A converter?

Accepted Answer

1023

Answer

1000

Answer

1024

Answer

1224