Interfacing Through Microprocessors March06 Rr310501

Set No. 1

Code No: RR310501

III B.Tech I Semester Supplementary Examinations, March 2006 INTERFACING THROUGH MICROPROCESSORS ( Common to Computer Science & Engineering, Information Technology and Computer Science & Systems Engineering) Time: 3 hours Max Marks: 80 Answer any FIVE Questions All Questions carry equal marks ⋆⋆⋆⋆⋆ 1. (a) If an absolute address of the type 6A3D9H is given, express it in the form of CS : IP and explain what are the advantages of the memory segmentation. Discuss about the various segment registers in 8086. (b) What are the modes in which the 8086 can be used .How many lines are there in the multiplexed bus of 8086. Give the pin diagram separately for each mode of operation. [8+8] 2. Show the 8086 instruction or group of instructions which will : (a) initialize the stack segment register to 4000H and stack pointer register to 8000H (b) call a near procedure named FIXIT (c) save BX and BP at the start of a procedure and restore them at the end of the procedure (d) return from a procedure and automatically increment the stack pointer by 8. [8+8] 3. Develop an 8086 assembly language program to compute nCr using recursive procedure. Assume n and r to be positive integers and place the binary result in a memory word location. [16] 4. (a) What kind of I/O interface does a 8255 implement, and how many I/O lines are available on the 8255 (b) What is the function of the port B lines of the 8255 when port A configured for mode 2 Operations (c) Explain about maximum mode interrupt interface

[6+4+6]

5. (a) Write about interrupt sequence in an 8086 system (b) Explain about command words of 8259 (c) Show interfacing schematic for connecting 13 interrupting devices to 8086 using 8259 [4+6+6] 6. (a) Design a circuit to activate a actuator, based on a bit combination given by eight switches interfaced to a microprocessor

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Set No. 1

Code No: RR310501

(b) Design a interface circuit to feed numbers 0-9 through a linearly encoded switches and to display the number on a seven segment LED through a microprocessor [8+8] 7. (a) Show the interface connections for a microprocessor based scheme for controlling a stepper motor and explain (b) Explain the interfacing circuitry needed to implement a Data acquisition system. [10+6] 8. (a) Write a program sequence which initializes the mode register and gives a command to enable the transmitter and begin an asynchronous transmission of 7-bit characters followed by an even parity bit and 2 stop bits. Explain the program. (b) Explain the following terms: i. ii. iii. iv.

Simplex, half-duplex and full duplex. baud rate. framing error. Over run error. ⋆⋆⋆⋆⋆

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[8+8]

Set No. 2

Code No: RR310501

III B.Tech I Semester Supplementary Examinations, March 2006 INTERFACING THROUGH MICROPROCESSORS ( Common to Computer Science & Engineering, Information Technology and Computer Science & Systems Engineering) Time: 3 hours Max Marks: 80 Answer any FIVE Questions All Questions carry equal marks ⋆⋆⋆⋆⋆ 1. Write short notes on the following: (a) Relative and based addressing modes of 8086 (b) Interrupt structure of 8086 (c) Use of CALL and RET instructions in executing procedures

[5+5+6]

2. (a) Develop an 8086 assembly language program to copy a block of data from memory location MEMA to MEMB. (b) Develop an 8086 assembly language program to sort a given set of 16-bit unsigned integers into ascending order using insertion sort technique. [8+8] 3. From the following pseudo code draw a detailed flowchart which indicates the elementary constructs and there by translate it into 8086 program. CODE← 0 IF A = 0 THEN IF B = 0 THEN CODE ← 1 ELSE CALL DIVIDE to compute X1← -C/B ENDIF ELSE CALL EVAL to compute E ← -B/2A CALL DISCRIM to compute D← (-B/2A)∧2 - C/A IF D < 0 THEN CODE ← 2 ELSE IF D = 0 THEN X1 ← E CODE ← 3 ELSE CALL SQROOT to compute F ← sqrt(D) CALL SUBTRACT to compute X1←E - F CALL ADDITION to compute X2←E + F ENDIF ENDIF. [16] 4. (a) Suppose that the beginning address of an 8255 is 0500 and write a program sequence that will 1 of 2

Set No. 2

Code No: RR310501

i. Put both groups A and B in mode 0 with ports A and C being input ports and port B as an output port. ii. Put group A in mode 1 with port A being an input and PC6 and PC7 being outputs and group B in mode 1 with port B being an input. (b) Explain interfacing I/O subsystem using an 8255 with one example.

[8+8]

5. (a) What is minimum no. of bus cycles that can occur between the time an interrupt request is recognized and the first instruction in the interrupt routine is fetched. Draw the bys cycles. (b) Write an instruction sequence that will cause the priority of an 8259, whose even address is 08A0, to be IR4, IR5, IR6, IR7, IR0, IR1, IR2, IR3. Solve this twice, once assuming that the highest priority is currently IR0 and once assuming that it is IR3. [6+10] 6. (a) Design a circuit to activate a actuator, based on a bit combination given by eight switches interfaced to a microprocessor (b) Design a interface circuit to feed numbers 0-9 through a linearly encoded switches and to display the number on a seven segment LED through a microprocessor [8+8] 7. With neat layout, explain how a microprocessor can be used for Data Acquisition System using A/D converters and D/ A converters [16] 8. (a) Explain the Handshaking signal sequence for a system using modem. (b) Write a short note on synchronous serial data communication. ⋆⋆⋆⋆⋆

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[8+8]

Set No. 3

Code No: RR310501

III B.Tech I Semester Supplementary Examinations, March 2006 INTERFACING THROUGH MICROPROCESSORS ( Common to Computer Science & Engineering, Information Technology and Computer Science & Systems Engineering) Time: 3 hours Max Marks: 80 Answer any FIVE Questions All Questions carry equal marks ⋆⋆⋆⋆⋆ 1. (a) With examples describe the various branch (control) instructions in 8086 microprocessor. (b) Give the general coding template format for 8086 instructions and describe each byte in detail. [8+8] 2. (a) What does the PUBLIC directive indicate when placed in a program module? (b) What does the EXTRN directive indicate when placed in a program module? (c) Explain how a library file works when it is linked to other files by the linker program? [4+4+8] 3. (a) Develop a 8086 assembly language program with a procedure named BCD BIN, which converts BCD numbers to binary. Use the AL register to pass parameters to the procedure. (b) How do you make the above procedure named BCD BIN as a re-entrant procedure? [8+8] 4. Design a multiplexed display scheme to display seconds, minutes and hours counter using 8255 ports. Assume that a standard delay of 1 second is available . [16] 5. (a) Draw a flow chart for interrupt processing sequence and explain. (b) Explain operational command words of 8259 with examples

[8+8]

6. (a) Design a circuit to activate a actuator, based on a bit combination given by eight switches interfaced to a microprocessor (b) Design a interface circuit to feed numbers 0-9 through a linearly encoded switches and to display the number on a seven segment LED through a microprocessor [8+8] 7. (a) Give the use of character generator ROM. (b) Explain with a block diagram how to interface parallel comparator ADC. Compare its merits and demerits. [4+12] 8. Interface 8251 with 8086 at an address 80H. Initialize it in asynchronous transmit mode, with 7 bit character size, band factor 16, one start bit, one stop bit, even parity enable. Further transmit a message ‘HAPPY NEW YEAR’ in ASCII coded form to a modem. [16] ⋆⋆⋆⋆⋆ 1 of 1

Set No. 4

Code No: RR310501

III B.Tech I Semester Supplementary Examinations, March 2006 INTERFACING THROUGH MICROPROCESSORS ( Common to Computer Science & Engineering, Information Technology and Computer Science & Systems Engineering) Time: 3 hours Max Marks: 80 Answer any FIVE Questions All Questions carry equal marks ⋆⋆⋆⋆⋆ 1. (a) If an absolute address of the type 6A3D9H is given, express it in the form of CS : IP and explain what are the advantages of the memory segmentation. Discuss about the various segment registers in 8086. (b) What are the modes in which the 8086 can be used .How many lines are there in the multiplexed bus of 8086. Give the pin diagram separately for each mode of operation. [8+8] 2. (a) Write an 8086 assembly language program to convert each byte of the code received from IBM PC to SDK 8086 Board, to ASCII codes for the nibbles in the byte. Use IF-THEN-ELSE. (eg:-7AH received is sent as 37 H ,the ASCII code for 7 and 41 for A). (b) Explain the following instructions of 8086 i. JL/JNGE ii. CWD iii. LAHF

[10+6]

3. (a) Develop a 8086 assembly language program with a procedure named BCD BIN, which converts BCD numbers to binary. Use the AL register to pass parameters to the procedure. (b) How do you make the above procedure named BCD BIN as a re-entrant procedure? [8+8] 4. (a) Describe memory-mapped I/O and direct I/O. Give the main advantages and disadvantages of each. (b) Show the truth Table for a 3625 PROM decoder to produce CSI signals for 4Kx8 RAMS in an 8086 system. Assume that the first RAM starts at address 00000H. Also draw the circuit convections. [6+10] 5. (a) Draw and discuss architecture of 8259 (b) Explain about interfacing of a DMA controller with 8086

[10+6]

6. Explain how a seven segment LED can be interfaced to the microprocessor. Give the hardware and software for it. [16] 7. (a) Explain how characters are displayed on CRT screen 1 of 2

Set No. 4

Code No: RR310501

(b) Explain in detail how CRT controller can be interfaced to Microprocessor. [4+12] 8. (a) Show the bit pattern for the mode word and the command word that must be sent to an 8251A to initialize the device as follows: band rate factor of 64, 7 bits / character, even parity, 1stop bit, transmit intercept enabled, receive intercept enabled, DTR and RTS asserted, error flags reset, no hunt mode, no break character. Explain. (b) Show the sequence of instructions required to initialize and 8251A at addresses 80H and 81H with the mode and command words as worked out in the above question. [8+8] ⋆⋆⋆⋆⋆

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