Microprocessor Viva Questions

Introduction to Microprocessor and Microcomputers

1. Define microprocessor.
2. Write application of microcontroller.
3. List the basic components of microcomputer.
4. What are the purposes of control unit in Microprocessor?
5. Mention one advantage and one disadvantage of Harvard architecture over von Neumann machine.
6. What is store programmed concept.

8086/8088 Architecture and Instruction Set

1. How many address and data bus are available in 8088 microprocessor?
2. How many minimum address lines are required to access 512 KB?
3. Explain in brief about how microprocessor works.
4. What is segment register in 8086? Explain its function.
5. With an example, explain the Register Indirect Addressing Mode.
6. Write an instruction for the direct addressing mode.
7. Identify the addressing mode of source operand in MOV AL, 23H. Give reason.
8. What happens when MUL BX instruction is executed?
9. What is the total memory capacity of the system with 20 address lines?
10. What is the result of MUL AL? Initial value of AL = 03H.
11. What happens when DIV BL executed.
12. What happens when DIV BX executed.
13. How many byte instruction is MOV AX,2304H?
14. How many byte instruction is MOV AL,23H?
15. Flag Register

OF

DF

IF

TF

SF

ZF

AF

PF

CF

16. BIU, EU, CS, DS, ES, SS, IP, AX, BX, CX, DX, SP, BP, SI, DI
17. What is opcode and operand?
18. Differentiate mov ax,2304h and mov ax,[2304h].
19. Differentiate mov ax,bx and mov ax,[bx].

Assembly Language Programming

1. What is assembler?
2. What is the role of linker?
3. Define one-pass assembler and two-pass assembler.
4. Differentiate between assembler and linker.
5. Assembler directives (data definition and storage allocation directives, end, proc and endp, dup)
6. .model, .stack, .data, .code
7. Some common DOS functions

INT 21H	01H, 02H, 09H, 0AH, 4CH
INT 10H	00H, 01H, 02H, 06H, 07H, 08H, 09H, 0AH

8. What happens when the instruction TEST AL, BL is executed?
9. What is the difference between JMP and LOOP? (TEST and LOOP, AND and TEST)
10. What is the function of INT 21H: mov ah, 01h ?

Hardware Architecture of 8086/8088

1. Write is the similarity and difference between 8086 and 8088 microprocessor?
2. Which signal is used to select Memory or I/O?
3. What are the purposes of S2, S1, S0?
4. What is the function of the ALE signal in 8086?
5. What do you mean by BHE?
6. What is the function of AD0-AD15 pins in 8086?
7. Why do we need maximum mode in 8086 MP? (MN/MX)
8. What is the role of DMA (Dynamic Memory Access) in MP? (HOLD, HLDA)
9. Differentiate between 8086 and 8088.
10. Define machine cycle. (instruction cycle, machine cycle, T-state)
11. Why do we need address decoding technique?
12. Function Chips (8288 bus controller, 8284 clock generator, 8286 transceiver, 8282 address latch).

8086 Interrupt Operations

1. What is interrupt?
2. What do you mean by Interrupt vector table(IVT)?
3. Why do we require INT 10H in assembly language?
4. Define NMI.
5. List the priority of 8086 interrupt.
6. List out the two software interrupts and two hardware interrupts.
7. List the 8086 interrupt types.
8. Define Vectored interrupt and Polled interrupt.
9. What is the function of INTO instruction?
10. What is ISR?

I/O Interfacing

1. Communication

Serial	Mode (simplex, half-duplex, full-duplex) Types (Synchronous, Asynchronous)
Parallel	Methods (simple, strobe, single handshake, double handshake I/O)

2. Define the terms: DTE and DCE with reference to serial communications.
3. Define RS-232.
4. What is control word to set Port A as output, Port B as input and port C as input for 8255.
5. What is the use of A0 and A1 pins of 8255?
6. Give control word to set PC-5 bit for 8255?
7. Give BSR control word to set and reset PC-3 separately for 8255.
8. What are the roles of 8251 in computers? (USART, PCI)
9. Why do we need PIC (Programmable Interrupt Controller)? (8259, 8259A)