B.E./B.Tech. DEGREE EXAMINATION, NOVEMBER/DECEMBER 2010
Fourth Semester
Computer Science and Engineering
CS 2252 — MICROPROCESSORS AND MICROCONTROLLERS
(Common to Information Technology)
(Regulation 2008)
Time : Three hours Maximum : 100 Marks
Answer ALL questions
PART A — (10 × 2 = 20 Marks)
1. Give any two single byte instructions that clear the accumulator register of 8085.
2. List the machine cycles involved in the execution of the following 8085 instructions: PUSH PSW; MOV A, M.3. List the pointer and index registers of 8086 architecture.
4. Identify the addressing modes involved in the following 8086 instructions:
MOV AX, 0005H; MOV AX, 50H [BX][SI].
5. What are the two internal sections of 8087 architecture?
6. What is the role of CCP in 8089 architecture?
7. What are the signals and instructions available in 8085 processor for serial I/O
communication?
8. What signals are required between a 8085 processor and an interrupt
controller for interrupt driven data transfer?
9. What are the functions of the following signals of 8051? ALE/PROG,PSEN .
10. What are the sources of interrupts in 8051?
PART B — (5 × 16 = 80 Marks)
11. (a) (i) List and explain the functions of flags in 8085 processor. (8)
(ii) Write an assembly language program using 8085 instruction set to
convert a string of ASCII characters into its hexadecimal
equivalent. (8)
Or
(b) (i) Identify the addressing modes and the number of T-states required
for the following instructions of 8085: MOV M,A; LXI SP,
addr.; LDAX D;ORA B. (8)
(ii) Discuss the features of 8085 processor for the support of interrupts
and DMA. (8)
12. (a) (i) Explain the register organization of 8086 processor in detail. (8)
(ii) Describe the various addressing modes of 8086 processor with
suitable examples for each. (8)
Or
(b) (i) What is the use of interrupts in microprocessor systems? With
suitable examples explain the sequence of operations done by a
microprocessor when it is interrupted. (8)
(ii) Explain how BIOS function calls are invoked in assembly language
programs. (8)
13. (a) (i) Explain the exception handling feature of 8087. (8)
(ii) Write a detailed note on the data types supported by 8087 in detail.
(8)
Or
(b) (i) With a neat sketch explain the general interconnections between
8086 and 8089. (10)
(ii) Distinguish between loosely coupled and closely coupled
multiprocessor systems with suitable examples. (6)
14. (a) (i) With a neat sketch, show all the interconnections required between
a 8085 processor and a RAM of size 4KB mapped in the address
range 2000H-2FFFH. (8)
(ii) Explain the data transfer on a parallel printer interface using a
timing diagram. (8)
Or
(b) (i) What are the signals a microprocessor should have to support
DMA? List and explain the sequence of operations carried out
during a DMA transfer. (8)
(ii) Explain the four modes of keyboard operation in 8279. (8)
15. (a) (i) Bring out the features of Special Function Registers of 8051
microcontroller. (8)
(ii) With a neat sketch of a Schematic diagram, explain the functions of
various signals of 8051. (8)
Or
(b) (i) Describe the various interrupts and their associated priorities in
8051 microcontroller. (8)
(ii) Write brief notes on ADCs mid DACs along with their interface
details. (8)