1. QUESTION BANK-Big questions
MICROPROCESSOR AND MICROCONTROLLERS
III YEAR CSE/IT
8085 MICROPROCESSOR
1. a. Draw the block diagram of 8085 mp and explain? (12)
b. Write an assembly language program to add two 2-digits BCD Number? (4)
2. a. Explain the instruction set of 8085? (10)
b. Write notes on status flag? (6)
3. a. Explain the architecture of Intel 8085 with the help of a block diagram? (12)
b. Explain the similarities diff b/w subtract and compare instructions in 8085? (4)
4. a. Describe the sequence of event that may occur during the different T state in the opcode
Fetch machine cycle of 8085? (8)
b. Write an assembly language program to convert on array of ASCII code to corresponding
Binary (hex) value. The ASCII array is stored starting from 4200H.The first element of the
number of elements in the array. (8)
5. a. With neat block diagram explain the architecture of 8085? (10)
b. List out the maskable and non maskable interrupts available in 8085? (6)
6. a. How do the instructions of 8085 is classified based on their function and word length?
Give an example? (8)
b. Write an ALP to Add two 8bit numbers? (8)
7.(a)Specify the contents of the registers and the flag status as the following
instructions are executed.(8)
i. MVI A, 00H
ii. MVI B, F8H
iii. MOV C, A
iv. MOV D, B
v. HLT
(b)Write instructions to load the hexadecimal number 65H in register C and 92H in
accumulator A. Display the number 65H at PORT0 and 92H at PORT1.(8)
8. (a)Why the lower order address bus is multiplexed with data bus? How they will be
de-multiplexed? (8)
(b) Differentiate between maskable and non-maskable interrupts.(8)
9. a)Write an 8085 assembly language program using minimum number of instructions to add the
16 bit no. in BC, DE & HL. Store the 16 bit result in DE pair. (8)
b) Explain the similarities diff b/w subtract and compare instructions in 8085? (8)
10. (a)Explain in detail the following instructions:-
(i) ADC (ii) LHLD (iii) RLC (iv) DI
(b) Define & explain the term addressing modes.

2. 8086 SOFTWARE ASPECTS AND 8086 SYSTEM DESIGN
1. a. Explain the addressing modes of 8086 with the help of examples? (12)
b. Write short notes on macro? (4)
2. a. Explain the instruction set 8086? (10)
b. Write an ALP in 8086 to find sum of numbers in array? (6)
3. a. Explain the addressing modes of 8086 with the help of example? (12)
b. Describe the action taken by 8086 when NMI pin is activated? (4)
4. a. Explain memory organization in 8086? (8)
b. Explain the following assembler directives (8)
i. ASSUME ii. EQU iii. DD IV. DW
5. a. With the neat sketch explain the architecture of 8086 processor? (12)
b. Give the significance of ‘O’ flag, ’T’ flag, ’I’ flag &’D’flag of 8086? (4)
6.a)Discuss the interrupt system of Intel 8086. What is interrupt pointer? What is 'type' of
an interrupt? (8)
b)Discuss the various addressing modes of 8086. What are displacement, base and
index? What is an effective address or offset? (8)
7. a)What is the difference between minimum and maximum modes of 8086? How are
these modes selected? (6)
b)Draw and explain the architecture of 8086.(10)
8 a)Write an 8086 program to add two 16-bit numbers in CX and DX and store the result
in location 0500H addressed by DI.(6)
b)Draw the maximum mode module of 8086 clearly showing address latches,
transreceivers, clock generator. neatly label the diagram. terminate unused pins properly.(10)
9.Draw the interfacing diagram for 8086 based system(minimum mode)with the
following specification.
-16 KB RAM
-8 KB EPROM
-8255 PPI in I/O address space also show the required latches, buffers and decoder .draw the
memory map for the above interface. (16)
10.a)Explain the following 8086 signals:(8)
-INTR
-DT/(R bar)
-RESET
-TEST (bar )
b)How does 8086 convert a logical address to physical address? explain with an example.(8)
11.a).Explain with the suitable diagram how 8086 access a byte or word from EVEN and ODD
memory banks.
b).State the differences between I/O mapped I/O and Memory mapped I/O.

3. 12.Explain with example ,various addressing modes of 8086/88 microprocessor (16)
13. a. Explain the Maximum mode of operation of 8086. (12)
b. Write short notes on addressing memory. (4)
14. a. Explain the minimum mode of operation of 8086. (12)
b. Write notes on addressing input and output devices? (4)
15. a. Design an 8086 based system in minimum mode containing 64kb of EPROM and
64kb of RAM (12)
b. Give the functions of NMI, BHE and TEST pins of 8086? (4)
16. Explain the various multiprocessor configurations. (16)
17. a. Discuss in detail the various signal of 8086. (10)
b. Explain in detail about 8086 memory banks and associated signals for byte and
word operations. (6)
18.a. Sketch and explain the interface of 32K x 16 RWMs using a decoder in minimum mode. (8)
b.Explain the difference between NEAR and FAR procedure of 8086 processor.
19.a)Explain the use of following instructions:
-XLAT
-DAA
-CMPSB
b).difference between CALL and JMP instruction of 8086 microprocessor.
20.a. Describe any four assembler directives used in 8086 assembly language
programming.
b. Write a program in 8086/8088 assembly language to convert string of character from
uppercase to lowercase. Accept the string of length 8 characters from user.
21. Explain the various assembler directives used while defining the data segment of 8086/8088
microprocessor. 16
22.a. Differentiate between MACRO and PROCEDURE . 8
b.. Write a program in MASM-86 assembly language to convert a two digit BCD
number into HEX. 8
I/O INTERFACING
1. Draw the Block diagram and explain the operations of 8251 serial communication
interface. (16)
2. Draw the Block diagram of 8279 and explain the functions of each block. (16)
3. Draw the block diagram of programmable interrupt controller and explain its operations.
(16)
4. Discuss in detail about the operation of timer along with its various modes. (16)

4. 5. Draw the Block diagram of DMA controller and explain its operations. (16)
6. Sketch and explain the interface of PPI 8255 to the 8085 microprocessor .Interface 4 7 segment
LEDs to display as a BCD counter
7. Sketch and explain the interface of 8279 to the 8085 microprocessor Interface 8x8 key pad
8.a. Draw the block diagram of 8255 and explain its working. What is Control Word? 12
Determine the control word for the following configuration of 8255:- 4
Port A – Output
Mode of port A – Mode 1
Port B – Output
Mode of port B – Mode 0
Port C lower (pins PC0 – PC2) – Output
10. Explain major components of 8259 with the aid of suitable diagram.
.
11. Explain the command words/control words of 8259(/8255/8279/8259/8251/8253) in
details.16/10/8 marks
12.a. What are the different modes of operation of the 8253 programmable timer? 10
b. Which mode will you use to generate a square wave ? Give a flow chart to generate it on 8253.6
13.a. Explain with neat waveform the mode 0 of the 8253 timer/counter.
b. Explain with the help of block diagram, functioning of 8253 in various programmable modes.
14. A 32-bit binary counter is to be implemented using timer/counter
i)design and explain the control word to meet above requirement
ii)Draw timing diagram of the mod(s) used.
MICRO CONTROLLERS
1.Describe the architecture of 8051 with a neat diagram.(16)
2. Explain the interrupt structure, SFR and timers of 8051.(16)
3. List out the salient features of 8051 Microcontroller.(16)
4. Explain the following instructions of 8051 with examples.(16)
i. CJNE destination, source, label
ii. MUL AB
iii. RRL A
iv. SWAP A
v. SETB P2.0
5. Discuss in detail stepper motor interfacing with 8051. (16)
6.Discuss in detail the interfacing of relay and optocouplers with 8051. (16)
7.Write a program to add N numbers.