MICROPROCESSORS AND INTERFACING (model questions) JNTU BTECH ECE 3-2The questions were framed to cover most of the topics (not all) in the JNTUK curriculum subject microprocessors and interfacing. Most of the questions appeared in old examination papers also. The marked questions are frequently asked. UNIT 1 1. a) Draw the architectural diagram and explain the function of each block in detail. b) What are the different r egisters in 8085 microprocessor? Discuss their function. 2. a) What are the addressing modes of 8085 microprocessor? b) Explain the flag register of 8085. 3. a) Explain various interrupt of 8085 microprocessor and their functionality. b) How is 8086 different from 8085? 4. Explain the architectural diagram of 8086. Explain the function of each block. 5. a) List the register set of 8086 microprocessor and explain the function of each one of them. b) Draw and explain the flag register of 8086. 6. Explain in detail the various addressing modes of 8086 microprocessor with examples. 7. a) Explain the instruction format of MOV instruction. b) Explain the instruction template of ADD instruction. c) Explain the instruction template of IN and OUT instructions. 8. Explain different data transfer instructions of 8086 microprocessor. 9. Explain different arithmetic instructions of 8086. 10. Explain different bit manipulation instructions of 8086. 11. Explain various string instructions of 8086. 12. Explain various execution transfer instructions of 8086. 13. Explain various processor control instructions of 8086. 14. a) What are assembler directives? Why are they required? b) Explain briefly various assembler directives of 8086. 15. a) Discuss briefly about prefetch queue of 8086. Explain when queue fail to speed up the ex ecution. b) Explain briefly the concept of memory segmentation. c) Discuss about multiplexing in 8086. 16. a) Explain the generation of physical address in BIU of 8086. b) Register content of 8086 is given below CS: 5000H, DS: 8000H, SS: 9000H, ES: 7000H, SI: 1000H, DI: 2000H, BP: 0008H SP: 0002H, AX: 0000H, BX: 5200H, CX: 8000H, DX: 2800H Calculate the effective and physical address of the following instructions. a) MOV AX,[BP+BX-24D] b) ADD AX,ES:[SI] c) PUSH CX d) SUB AX,[DI] e) MOVSB f) CMP AX,[DI] g) ADD DX,[DI+8D] h) MUL AX,[SI+2D] i) IMUL AX, [BP+BX-8D] j) SBB AL, ES:[SI+5D] k) PUSH AX l) AND AH, [SI+42D] m) CMPSB n) CMP DX, [SI] o) XOR DH, [DI+8D] p) DIV AX, [SI+2] 17. a) Explain the importance of procedure in assembly programming of 8086. b) Explain briefly about PUBLIC and EXTERN directives. 18. a) Explain the assembly program development process with a neat flow chart. b) Explain the function of MACRO assembler directive. UNIT 2 1. a) How does a near CALL and RET instruction works. b) Write a near procedure that cubes the content of CX register. The procedure may not affect any register except CX r egister. 2. Write an algorithm assembly program to sort the numbers in an array in descending order using bubble sort method. 3. Write a recursive routine to evaluate the following polynomial Y = A0 +A1 X1 +A2 X2 +A3 X3 +....+ANXN. The coefficients A0 , A1 , A2 ....AN are to be successive words in memory and all parameter addresses are to be passed via the stack. The size of SRAM chip is 32KB. 10. Explain the difference between Static RAM and Dynamic RAM. Draw the functional pin diagram of 8086 microprocessor and explain the pins. 19. UNIT 3 1. CX to 32bit content of BX. a) Write a program to check whether the given string is a palindrome or not. 9. AX. Design the address decoder for the address range from 00000H . Give the complete memory interface and also the address map for individual chips. Explain how EPROM is interfaced to 8086. 18. Repeat for unpacked BCD numbers. 6. The expansion slot address map is from 80000H to 8FFFFH. a) Write an ALP in 8086 to move a string of data words from offset 2000h to offset 3000h and the length of the string in 0Fh. 8. Write a assembly language program that will examine a string of 100 characters and replace digital digit by a %. b) Develop a assembly language program to multiply two BCD numbers of two digits each. 13. b) Write a delay loop for the delay of 500 msec on an 8086 with 8Mhz clock. b) Write an ALP in 8086 to multiply a 16-bit unsigned number by an 8-bit unsigned number. 5. a) Write an ALP in 8086 to find add two 16-bit BCD numbers. 17. b) Write an ALP in 8086 to find the average of two numbers. 15. otherwise continue in sequence. Draw a block diagram to interface two 16K X 8 SRAM (62128) to the 16 -bit data bus of 8086 based system. b) Develop a near procedure to find the GCD of two numbers of 2 digit hex. b) Write an assembly language program to display the message “JNTU KAKINADA ” on the CRT screen of micro-computer. a) Using loop instruction write a sequence to add two 16 digit 10’s complement packed BCD number. With neat circuit and timing diagram explain the maximum mode operation of 8086. b) Write an ALP in 8086 to count the number of 0’s in a 16-bit binary string. 4. a) Write a sequence that will convert the integer in binary to four ASCII coded hexadecimal digit and put the result in ASCII-STG. 3. Give the instruction sequence that compares the first 10 bytes beginning at STRG1 with the first 10 bytes beginning at STRG2 and branches to MATCH if they are equal. 5. Give the relevant interface diagram and signals for interfacing of EPROM. 7. 6. a) Write an ALP in 8086 to find the maximum number in an array of 10 numbers. 12. Explain how SRAM is interfaced to 8086. 7. 9. The program n eeds to terminate on 'ctrl+c' key combination.4. b) Develop a macro called ADD32 that add 32 bit content of DX. Give the releva nt interface diagram and signals for interfacing of SRAM. a) Write an assembly language program in 8086 for the addition of a series of 8 -bit numbers. b) Explain with illustration conversion of an ASCII coded decimal number into its binary equivalent. Explain briefly the functioning of EPROM. a) Write an ALP in 8086 to find the LCM of two 16-bit unsigned numbers. b) Write a recursive program to find the sum of first N integers. a) Write an ALP in 8086 to add two ten byte numbers available in array1 and array2 and store result in array3. b) Write an ALP in 8086 to exchange a block of N bytes between source and destination. a) Write an ALP in 8086 to add 5 bytes of data in an array by making use of procedure. With neat circuit and timing diagram explain the minimum mode operation of 8086. Explain the architecture of 8086 in minimum and maximum mode with their relevant pins. Use this procedure to find GCD of three numbers. The on system SR AM address map is from 00000H to 0FFFFH and that of EPROM is from F8000H to FFFFFH. EPROM chip size is 16KB. 16.07FFFH for both the SRAMs. 14. The character string starts at STR. 11. 2. 8. . b) Write an ALP to divide a 32-bit number with 16-bit number. In an SDK-86 kit 64KB SRAM and 32KB EPROM is provided on system and provision for expansion of another 64KB SRAM is given. 10. a) Develop a PUBLIC procedure to conver t 4-digit hex to BCD and return the value. a) Write an ALP in 8086 to count number of positive and negative numbers from an array of 8 -bit integers. a) Write a recursive program to find the factorial of a given number. SRAM with their cell structure. Develop an assembly language program in 8086 that read a key from the keyboard and convert to uppercase before displaying it. b) Write a convert a given packed BCD number into its ASCII equivalent. Explain why interrupt priorities are needed and how 8259 provide interrupt priority. Explain the interfacing of 8257 with 8086 using a circuit diagram. Address of SRAM starts from 00000H and that of EPROM is from E0000H. 16. Explain the functioning of scanning. Interface an 8255 with 8086 to work as an I/O port. 12. What is interrupt service routine? Explain briefly the interrupt structure of 8086 using interrupt vector table. 9. Explain the DAC interface to 8086 using neat diagram. 5. Interface a 4*4 keyboard with 8086 using 8255 and write an ALP for detecting a key closure and return the key code in AL. Write an ALP in 8086 to generate a symmetrical square waveform with 1KHz frequency? Give the nec es sary circuit setup with a DAC? Explain the architecture and functioning of keyboard display interface 8279 using a block diagram.11. Use port A of 8255 for transferring digital data output of ADC to the CPU and port C for control signals. 9. Draw the schematic and write required ALP. 3. It is necessary to interface 512KB SRAM and 128KB EPROM to an 8086 based system. Design the entire memory interface? Give the address map of individual chip. UNIT 5 1. 8. Explain the INTEL predefined interrupts of 8086. Explain the need of DMA. 11. 16. 13. debounce. The debouncing period for a key in 10ms.show the interfacing of 8255 with 8086 in mode1. The transfer is to take place using channel 0. . Explain the operation of 8255 in mode2 with example. to which 8 LEDs are connected. Assume that an analog input is present at I/P2 of the ADC and a clock input of suitable frequency in available for ADC. Explain the function of mode set control word and BSR control word of 8255. which the port C lower displays number of on switches out of the total eight switches. 17. Explain the architecture of programmable interrupt controller 8259 using a block diagram. autoload is not required. 13. Write a delay routine for 1 millisecond after ea ch step movement. Initialize port A as output port. Explain briefly the various DOS and BIOS interrupts. Draw the circuit for interfacing 8255 with 8086 in mode2. Explain the interfacing of a stepper motor with 8086 using the ports of 8255? Write an algorithm for driving a stepper motor. With a neat block diagram explain the architecture and features of 8255. Interface DAC AD7532 with an 8086 CPU resuming at 8MHz and write an assembly language program to generate a saw tooth waveform of period 1ms with Vmax 5V. 10. 17. Explain the ADC interface to 8086 using neat diagram.Write a program to sense switch positions SW0 –SW7 connected at port B. The size of SRAM and EPROM chips is 64KB. Briefly explain the DMA transfer method. Design a memory interface in an 8088 based system with 64KB SRAM and 16KB EPROM. With a neat block diagram explain the working of 8257 DMA controller. 14. Use 74LS138 decoder. The sensed pattern is to be displayed in port A. 6. port B as input port and port C as output port. Explain the interfacing of 8237 with 8086 using a circuit diagra m. 2. 5. With a neat block diagram explain the working of 8237 DMA controller. Port A address should be 0740H. 7. 3. UNIT 4 1. 4. 7. 14. Explain the interfacing of a 7-segment display with the 8086 using 8255. 2. 18. Use software key bouncing technique. Explain in detail the various modes of 8255. All the memory chips are of size 16KB. The SRAM starts at 00000H address and EPROM ends at FFFFFH. Assume that the desired direction stored in BL and the number of steps is stored in CL. Explain the interrupt sequence in 8086 microprocessor. Initialize the 8257 with normal priority. 15. Interface ADC 0808 with 8086 using 8255 ports. Explain the stack with its importance in single and nested interrupt in 8086. Explain various modes of 8259. Explain the (ICW’s) initialization command words and (OCW’s) operational command words of 8259. How can I enable 8086 to operate in single or nested interrupt? 4. 6.write an ALP to move 2KB of data from a peripheral device to memory address 2000:5000H with the above initialization. 8. Explain the software and hardware interrupts of 8086. Explain the input and output status words of 8255 in mode1. 12. Interface DMA controller 8257 with 8086 so that the channel 0 DMA address register has an I/O address 80H and the mode set register has an address 88H. decoding of a key on 4*4 keyboard. TC stop and non extended write. 15. Design a hardware interfacing circuit for interfacing 8251 with 8086. Give the modes defined for cascade system in 8259. Explain the protected virtual address mode in 80286. Explain the synchronous and asynchronous serial data transfer schemes with examples. The address of memory map should start from 0000H. Discuss in detail about parallel I/O ports in 8051 microcontroller. Write an initialization sequence for an 8259 in an 8086 based system. Explain the various timer modes in 8051. 9. 9. Draw the diagram to Interface Program memory of 16K x 8 EPROM to 8051and give its memory map. Explain the RS232C serial communication standard and its specifications. UNIT 6 1. Explain the internal and external program memory as well as data memory of 8051 with the diagram showing their capacities. What are descriptors? Explain local and global descriptor table and their importance in protection in 80286. 7. iv. 11. What is difference between CISC and RISC processor? Explain the Architecture of any RISC processor. Explain the paging and segmentation of virtual memory in 80386. What is the importance of SFR’S TCO N and TMOD in timer operations? 7. 8. Explain the importance of cascade operation of 8259. Request to the edge trigger ed mode ii. SBUF special function registers. Write an ALP to transmit 100 bytes of data string starting at location 2000:5000H. 2 stop bits. vi. What are the salient features of Pentium? 10. Explain the interrupt structure of 8051 microcontroller. Also explain how these ports are accessible for specific applications. Explain the salient features of 80286. SP/EN to output a disable signal to the data bus transceivers. The ISR bits to be cleared automatically at the end of second INTA pulse. Set the 8251A in asynchronous mode as a transmitter and receiver with even parity enabled. Explain briefly mode word. Explain the real and protected mode operation in 80386.10. Explain in detail the serial port communication in 8051 with SCON. Interface Data memory of 16K x 8 SRAM to 8051 and give memory map. With a neat circuit diagram explain the interfacing of 8251 with 8086 microprocessor. 5. 11. Explain with a block diagram the architecture and functioning of 8051 microcontroller. The highest priority i nterrupt will be IR6. 12. with an even address of 0A0H that will cause i. How master and slave 8259 work differently in cascade system of PIC. 3. v. Explain the addressing modes of 8051. Explain the working of USART 8251 with a neat architectural block diagram. 7. Explain the real and protected mode segmentation in 80286. What are the special function registers of 8051. 2. 4. status word of USART 8251. 8. fr equency 160 KHz and baud rate 10K. Explain the salient features of 80386. What is a microcontroller? What are the differences between microcontroller and microprocessor? 2. 2. 10. IR0 request to an interrupt type 30 iii. 6. 12. 6. Explain the conversion of linear address to physical address in 80286. The IMR to be cleared. Write an 8086 instruction sequence for receiving 50 characters using 8251 and store them in memory at location 2080H. 6. 3. Explain the conversion between RS232C and TTL standard. 5. explain them briefly. Give the interface circuit between 8259 and 8086 microprocessor. 4. . 5. The Starting address of SRAM should be 0000H. 8. 3. Explain the memory and register structure of 8051 micr ocontroller. 4. command word. UNIT 8 1. UNIT 7 1. 8-bit character length.