8086 Question

MICROPROCESSOR Long Questions 1) 2) 3) 4) 5) 6)

Draw & explain the pipeline architecture of INTEL 8086. ** What is segmentation? Explain the memory segmentation technique of 8086. * Explain the different addressing modes of 8086 with examples. ** How the logical address in 8086 is converted to physical address, explain. ** Draw the interrupt vector table & explain the 8086 interrupt system. * Draw the minimum/maximum mode read/write bus cycle of 8086 (with wait states). ** 7) WAP to read the DIP switches connected in port B of 8255 display the value in port A in mode0. 8) Draw the 8086 minimum mode system & explain? 9) Write an ALP using 8086 instruction to find the largest/smallest no. from an array of 16-bit numbers. * 10) Write an ALP using 8086 instruction to copy a string of 50 bytes from memory address 52000H to 65000H. ** 11) Write an ALP using 8086 instruction to search the presence of a byte 50H in a string of 40 bytes present at memory 61000H. 12) Write an ALP using 8086 instruction to multiply two 16-bit numbers. 13) Explain de-multiplexing of buses in 8086. * 14) Interface a 64K RAM and 32k ROM with 8086 and calculate the physical address.** 15) Interface an 8251 with 8086 and explain the function of command words. 16) Draw and explain the different modes of operation of 8254 clock generator. 17) Draw and explain minimum/maximum mode 8086 system. 18) Draw and explain the register organization of 8086. 19) Write an ALP using 8086 instruction to add an array of 16-bit numbers using whiledo. The array contains 5 numbers with a starting address of 24050H.** 20) Write an ALP to convert a binary no. to gray.** 21) Write an ALP to convert a decimal no. to hexadecimal. 22) Write an ALP using 8086 instruction to swap the bytes of a 16-bit no. 23) Explain the different instruction format of 8086 microprocessor. Short Questions 1) What is the difference between the minimum & maximum mode of 8086. Ans: Min Mode Max Mode MN/ =1 MN/ =0 Uniprocessor Multiprocessor No bus controller External bus controller 8288 used 2) What is assembler directive? Ans: - An assembler directive is a message to the assembler that tells the assembler something it needs to know in order to carry out the assembly process or Assembler directives are instructions to the assembler to perform various bookkeeping tasks, storage reservation, and other control functions. Ex- EQU, ORG etc 3) What is the function of Index registers of 8086. How many index registers are there. Asst. Prof. SATYANARAYAN PRADHAN

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MICROPROCESSOR Ans: - They hold the offset for data and extra segment. Two index registers SI & DI. 4) What is the difference between carry and overflow? Ans: - Overflow indicates carry for signed numbers. It is the excess bit at D 6 in case of 8-bit and D14 in case of 16-bit number. Carry occurs at the MSB in case of unsigned numbers. 5) What is the function of direction flag in 8086? Ans: - To set the direction of string access. DF=1, String bytes are accessed from higher memory address to lower memory address and if DF=0, String bytes are accessed from lower memory address to higher memory address. 6) In INTEL 8086 why the segment registers are appended by 0 to generate physical address? Ans: - Because when segment registers are appended by 0 the generate the starting address of the segment which is then added with the offset to give the physical address. 7) Which register holds the address of the next instruction to be executed? Ans: - PC in 8085 and [CS:IP] in 8086 microprocessor. 8) What is BSR & IO mode of 8255? Ans: - BSR mode is used to set or reset the Port-C bits where IO mode is used for data transfer. 9) Why CS can be a source but can’ be a destination. Ans:- Because CS holds the segment address of executable program codes which should not be changed not to affect the program execution. 10) List out the segment and index registers of 8086. Ans: - CS, DS,ES,SS as segment registers and SI & DI as index registers. 11) How much memory can be active at a given time in 8086? Ans: - Four segments each of 64K, Total 256K of memory active. 12) What is the difference between memory mapped IO and IO mapped IO technique. 13) What is the function of QS1 and QS0. 14) Draw an instruction word format. 15) What is the difference between synchronous and asynchronous data transfer? 16) What do you mean by word length of a processor? What is the word length of 8086? Ans: - Processing capacity. 16-bit. 17) Write down the specification of 8086? Ans: - 16-bit, 1M address space, 5/8/10 Mhz clk, +5v power supply, 40pin DIP VLSI chip, HMOS technology, 14 word. 18) What is the addressing capacity of 8086 & why? Ans: - 220=1M due to the presence of 20 address lines. 19) Enumerate the interrupt signals of 8085. Ans: - H/W- NMI & INTR S/W – INT n (n=0 to 255) i.e type0 to type 255. 20) What are the address space partition schemes are used by the processors? Ans: - Memory mapped IO & Io mapped IO. 21) Theoretically using IO mapped IO scheme how many IO devices can be connected with 8086. Asst. Prof. SATYANARAYAN PRADHAN

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MICROPROCESSOR Ans: - Theoretically 220=1M. Practically 28 =256. 22) What is the difference between maskable and non-maskable interrupts? Ans: - Non-maskable interrupts can never be made ineffective. 23) List out the h/w and s/w interrupts of 8086. 24) Draw the 8086 flag register. 25) What is the difference between control and status flags of 8086? 26) WAP to clear the content of flag register without using any arithmetic or logic instruction. Ans:- MOV AX,0000H MOV SP, 4000H PUSH AX POPF 27) What is the vector address (CALL Location) for RESET in 8086 microprocessor. Ans:- FFFF0H 28) What are the different display modes available in 8279. 29) Implement an IF-THEN-ELSE structure using 8086 instruction. 30) What is difference between 8086 & 8088. Short Notes 1) 2) 3) 4) 5) 6) 7)

8288 Bus controller** Interrupt Processing** DMA state Addressing Modes of 8086 Maskable Interrupt 8286 transceiver** 8279 Keyboard/Display controller

Instructions:- PUSH , POP, SHIFT, ROTATE, LDS, LES, LEA, MUL, DIV, CMP, MOVSB, LODSB, STOSB, SCASB, LAHF, SAHF. Directives:- GLOBAL, PROC, ORG, ASSUME, TYPE, OFFSET,EQU, EXTERN, PUBLIC. Pins:- ALE, MN/MX, TEST, READY, BHE, QS1 & QS0, HOLD & HLDA, LOCK, RQ/GT, NMI.

Asst. Prof. SATYANARAYAN PRADHAN

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