BEE Digital Logic and Microprocessors 3 — Questions and Answers
Question 1: Which of the following is a universal gate?
- AND
- OR
- NAND (Correct answer)
- XOR
Correct answer: NAND
NAND is a universal gate because any Boolean function can be implemented using only NAND gates.
Question 2: What is the decimal equivalent of the 2's complement binary number 11110000?
- -16 (Correct answer)
- -15
- 240
- -240
Correct answer: -16
11110000 in 2's complement: invert to 00001111 = 15, add 1 = 16, so the value is -16.
Question 3: In a D flip-flop, what is the relationship between output Q and input D at the clock edge?
- Q becomes D'
- Q becomes D (Correct answer)
- Q toggles
- Q is unchanged
Correct answer: Q becomes D
A D flip-flop captures the value of D at the active clock edge and transfers it to Q.
Question 4: A multiplexer (MUX) with 3 select lines has how many data inputs?
- 3
- 6
- 8 (Correct answer)
- 16
Correct answer: 8
A MUX with n select lines has 2^n data inputs; 2^3 = 8 data inputs.
Question 5: Which interrupt type cannot be disabled by software in most microprocessors?
- Maskable interrupt
- Non-maskable interrupt (NMI) (Correct answer)
- Software interrupt
- Timer interrupt
Correct answer: Non-maskable interrupt (NMI)
Non-maskable interrupts (NMI) cannot be disabled by the programmer and are used for critical hardware events.
Question 6: In synchronous sequential logic, what determines when state transitions occur?
- Input signal changes
- The clock signal (Correct answer)
- Output feedback
- Reset pulses
Correct answer: The clock signal
In synchronous circuits, all state transitions are triggered by the clock signal's active edge.
Question 7: What does the acronym ALU stand for in microprocessor architecture?
- Algorithmic Logic Unit
- Arithmetic Logic Unit (Correct answer)
- Address Logic Updater
- Asynchronous Latching Unit
Correct answer: Arithmetic Logic Unit
ALU stands for Arithmetic Logic Unit, the component that performs arithmetic and logical operations.
BEE Digital Logic and Microprocessors 3
Which of the following is a universal gate?