Free Bachelor of Computer Engineering Microprocessor Questions and Answers — Questions and Answers

Question 1: What is a Microprocessor?

A multipurpose PLD that accepts whole numbers as input
A multipurpose PLD that accepts prime numbers as input
A multipurpose PLD that accepts binary data as input (Correct answer)
A multipurpose PLD that accepts an integer as input

Correct answer: A multipurpose PLD that accepts binary data as input

A microprocessor is fundamentally a programmable logic device (PLD) designed for general-purpose computation. It operates by executing instructions that manipulate data, and all data within a digital computer system, including inputs, instructions, and results, is represented and processed in binary form.

Question 2: What statement concerning the 8086 microprocessor is true?

STMICROELECTRONICS’s first x86 processor
NanoXplore x86 processor
Intel’s first x86 processor (Correct answer)
Motrola’s first x86 processor

Correct answer: Intel’s first x86 processor

The Intel 8086, released in 1978, was a pivotal microprocessor. It was indeed Intel's first processor to implement the x86 instruction set architecture, which became the foundation for nearly all subsequent Intel and compatible CPUs, dominating the personal computer market for decades.

Question 3: What form of computer hardware is a microprocessor?

RISC
EPIC
CISC
All of the above (Correct answer)

Correct answer: All of the above

Microprocessors are designed based on various architectural philosophies. CISC (Complex Instruction Set Computer) and RISC (Reduced Instruction Set Computer) are two major categories that describe different approaches to instruction set design. EPIC (Explicitly Parallel Instruction Computing) is another architectural paradigm, exemplified by Intel's Itanium, which also falls under the umbrella of microprocessor design.

Question 4: Any information can be processed by a computer's microprocessor if it is only present in .

Main Memory (Correct answer)
Secondary Memory
Program Counter
Flag

Correct answer: Main Memory

A computer's microprocessor can only directly process information that resides in its main memory (RAM). Data and instructions must be loaded from secondary storage into RAM before the CPU can fetch and execute them. The program counter and flag register are internal CPU components, not memory locations for general data.

Question 5: Intel created its first 8-bit microprocessor using which of the following technologies?

HMOS
TTL
NMOS
PMOS (Correct answer)

Correct answer: PMOS

Intel's first 8-bit microprocessor, the 8008 (released in 1972), was indeed fabricated using PMOS (P-channel Metal-Oxide-Semiconductor) technology. PMOS was an early and relatively simple semiconductor manufacturing process, preceding NMOS and CMOS in widespread use for microprocessors.

Question 6: The instruction MOV AX,[BX] represents which of the following addressing methods?

register addressing mode
register relative addressing mode
direct addressing mode
register indirect addressing mode (Correct answer)

Correct answer: register indirect addressing mode

In the instruction `MOV AX,[BX]`, the square brackets around `BX` indicate that the value in the `BX` register is to be interpreted as a memory address. The data at this memory address is then moved into the `AX` register. This method, where a register holds the effective address of the operand, is known as register indirect addressing.

Question 7: How many words can an 8-bit CPU process?

8-bits – 16 bits
8-bits – 32 bits
8-bits – 64 bits (Correct answer)
4-bits – 32 bits

Correct answer: 8-bits – 64 bits

An 8-bit CPU's native word size is 8 bits, meaning it processes data in 8-bit chunks. However, through multiple instruction cycles and software techniques, it can manipulate and process larger data types, such as 16-bit, 32-bit, or even 64-bit 'words' by breaking them down into 8-bit operations. Therefore, while its fundamental unit is 8 bits, it can effectively handle data up to 64 bits in size.

Question 8: How many opcodes are there in an 8-bit processor?

250
256
246 (Correct answer)
278

Correct answer: 246

An 8-bit processor uses an 8-bit opcode, which theoretically allows for 2^8 = 256 unique opcodes. However, not all possible 256 combinations are typically used as valid instructions. Some combinations might be reserved, invalid, or used for multi-byte opcodes. The number 246 represents a common practical count of distinct opcodes found in many 8-bit processors, such as the Intel 8085.

Question 9: Which of the following statements regarding the address bus is false?

It is a bidirectional bus (Correct answer)
Lower address bus lines (AD0 – AD7) are called “Line number”
It consists of control PIN 21 to 28
It is 16 bits in length

Correct answer: It is a bidirectional bus

The address bus is fundamentally a unidirectional bus. Its sole purpose is to transmit memory addresses from the CPU to memory or I/O devices, indicating where data should be read from or written to. Data buses are bidirectional, but address buses only carry information in one direction (out from the CPU).

Question 10: What statement concerning microprocessors is correct?

It has interfacing circuits
It uses Harvard architecture
It has an internal memory
It contains ALU, CU, and registers (Correct answer)

Correct answer: It contains ALU, CU, and registers

A microprocessor's core components include the Arithmetic Logic Unit (ALU) for performing calculations and logical operations, the Control Unit (CU) for managing and coordinating all operations, and a set of registers for temporary data storage during processing. These three elements are essential for its function as a central processing unit.

Question 11: Which of the following describes how a microprocessor should operate?

I/O read, opcode fetch, memory read, memory write, I/O write
I/O read, opcode fetch, memory write, memory read, I/O write
Opcode fetch, memory read, memory write, I/O read, I/O write (Correct answer)
Opcode fetch, memory write, memory read, I/O read, I/O write

Correct answer: Opcode fetch, memory read, memory write, I/O read, I/O write

The fundamental operation cycle of a microprocessor begins with fetching an opcode (instruction) from memory. This is followed by memory read/write operations to access operands or store results, and I/O read/write operations to interact with peripheral devices. This sequence represents the typical order of operations for executing instructions and interacting with the system.

Question 12: The _______ directive tells the assembler to start allocating memory for a segment, block, or piece of code at the specified address.

LABEL
OFFSET
GROUP
ORG (Correct answer)

Correct answer: ORG

The `ORG` (Origin) directive in assembly language is used to specify the starting address in memory where the subsequent code or data should be loaded or assembled. It tells the assembler to set its location counter to the specified address, thereby controlling the memory layout of the program.

Question 13: Among the following, which one is not a microprocessor?

Motorola 6809
PIC1x (Correct answer)
Z8000
Zilog Z8

Correct answer: PIC1x

The Motorola 6809, Z8000, and Zilog Z8 are all examples of microprocessors, which are standalone CPU chips. PIC1x, however, refers to a family of PIC microcontrollers. Microcontrollers integrate a CPU, memory, and I/O peripherals onto a single chip, making them distinct from standalone microprocessors.

Question 14: Which of the following does not apply to the microprocessor's TRAP interrupt?

It uses edge-triggered signal (Correct answer)
It is a vectored interrupt
It is a non-maskable interrupt
It is of highest priority

Correct answer: It uses edge-triggered signal

The TRAP interrupt in many 8-bit microprocessors (like the 8085) is typically a level-triggered interrupt, not edge-triggered. It is indeed a non-maskable, vectored interrupt with the highest priority, designed for critical events that cannot be ignored.

Question 15: Which of the following describes a RST 7.5 interrupt's characteristics?

It uses level-triggered signal
Its vectored address is 003C H (Correct answer)
It is a non-maskable interrupt
It has 3rd highest priority

Correct answer: Its vectored address is 003C H

For the 8085 microprocessor, the RST 7.5 interrupt is a vectored interrupt. When triggered, the program counter is automatically loaded with a specific address, which for RST 7.5 is 003C H. This directs the CPU to a predefined service routine for that interrupt.

Question 16: Which of the following describes a microprocessor's special-purpose register?

Instruction register
Temporary register
Program counter (Correct answer)
Accumulator

Correct answer: Program counter

A program counter (PC) is a special-purpose register within the CPU that holds the memory address of the next instruction to be fetched and executed. It is crucial for controlling the flow of program execution. While other registers like the accumulator and instruction register are also important, the PC's role in instruction sequencing makes it distinctly special-purpose.

Free Bachelor of Computer Engineering Microprocessor Questions and Answers

What is a Microprocessor?