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EC4 05

USN 1 MIS

M.S. RANLAIAH INSTITUTE OF TECHNOLOGY(AUTONOMO US INSTITUTE, AFFILIATED TO V TU)

BANGA LORE - 560 054SUPPLEMENTARY SEMESTER EXAMINATIONS - 2010

Course & Branch : B.E (Electronics & Communication Engg . ) Semest er I V

Subec : Microprocessors Max. Marks 100

Subject Code : EC405 Duration,;: : 3 hrs

Instructions to the Candidates:Answer one full question from each unit.

UNIT-I

1. a) Explain all the user programmable reDescribe their general and special usmodel.

gisters,

es . Alsoof

w8086

rite themicropro

progrcessor

amming

. ( 12)

b) Explain the following with reference to 80(i) Even and odd addresses ( ii) Multiprog

(iii) Multiprocessing ( iv) Real mode mem

86 mic

ramminory ad

roprg

dres

ocessor

sing

: ( 08)

2. a) Explain the features of Intel 8086 microp rocesso r ( 06)

b) Indicate how the different segments of 8you mean by segment override prefix?

086 are us ed by de fault . What do ( 06)

c) With reference to the internal architectur e of 808 6 m icroprocessor: ( 08)(i) How does ppelining increase its throughput?(ii) Explain which flag bit controls the INTR pin on the microprocessor.(iii) What is the purpose of IP register?(iv) What is the function of SP register?

UNIT-II

a) Describe the data related addressing modes of 8086 with an example for (08)each.

b): Expan the LEA LDS LESinst ruct ions of 8086. (06)

Write::, an 8086 assembly language program to interchange 2 blocks of (06)

word data (10 words) using stack related instructions.

4. a) State if the following statements are meaningful and valid in an 8086 ALP, (08)if valid indicate what action they would perform, else give reasons as to

why they are invalid.

(i) MOV SS,DS (ii) MOV AL,BX(iii) XCHG AX,[SI] (iv) PUSH [SI]

b) What are assembler directives? Mention the assembler directive used to (04)assign a label to a constant, with an example.

c) Explain the string data transfer instructions of 8086. Clearly explain the (08)role of SI, DI registers and the direction flag. Also explain the use ofRepeat prefix with string instructions.

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EC405UNIT-III

5 a) Consi der the f ol owng8086 programcode: (06)MOV AL,28HMOV BL,89HADD AL,BLDA AWhat would be the results in AL and BL when the first three instructionsare executed? What will be the carry and auxiliary carry flag conditionsthen? After the fourth instruction is executed, what would be the results inAL and BL and what will be the flag conditions? Explain.

b) Write an 8086 assembly language program to find the number ofpositive (06)and negative numbers among the ten 16 bit numbers stored in a memoryblock starting with the address BLOCK. Store the counts in locationsPCOUNT and NCOUNT respectively.

c) Write an 8086 assembly language program to find the average of 10 bytes (08)stored in a byte memory block, staring with address NUM and store the

result in location AVG.

6. a) Indicate the resut of mutiplication and status of conditiona flags when (06)

the two signed data 07H and F5H are multiplied using signed multiplication

instruction.b) Which JMP instruction allows the program to continue execution at any (06)

memory location in the system? How many bytes does this instructionrequire? Explain them.

c) Write an assembly language program in 8086 to multiply ASCII.string by (08)

an ASCII digit. Result should be stored;in a BCD string.

UNIT-IV7. a) What is modular programming? What are its advantages? (06)

b) Write a 8086 procedure to read one decima number (0-9) from the (08)

keyboard and return its binary value in AX.c) Expan the 8284 cock generator wth a dag am (06)

8. a) Differentiate clearly between procedures and macros. (04)b) Explain the three ways to read a keyboard, using INT 21H. (06)c) Explain with appropriate diagrams how an 8086 processor is interfaced to (10)

a bus? What is the need for the use of latches and buffers in the interface?

UNIT-V

9. a) Explain briefly the interrupt system of 8086. Also explain the action taken (08)

b )

by 8086 when NMI line is activated.Draw and explain the circuit for converting INTR into an edge-triggered (08)

interrupt request input.c) Explain any two data formats used for the arithmetic coprocessor. (04)

10. a) In 8086 which software instructions call an interrupt service procedure? (04)Explain them briefly.

b) Give the register level description of 8087 processor and briefly explain its (10)

operations.c) Expan t he man f eatures of USBbus. (06)

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