B.E./B.Tech. DEGREE EXAMINATION, APRIL/MAY 2010
Computer Science and Engineering
CS2252 — MICROPROCESSORS AND MICROCONTROLLERS
(Common to Information Technology)
Time: Three hours Maximum: 100 Marks
Answer ALL Questions
PART A — (10 × 2 = 20 Marks)
1. Assume that the accumulator contains data bytes 82H and the instructionMOV C, A (4FH) is fetched. List the steps in decoding and executing the
2. What are the second bytes in the instruction IN and OUT of
3. Draw the 8086 flag register format.
4. List different types of 8086 hardware interrupts.
5. Compare closely coupled configuration with loosely coupled configuration.
6. Mention the need for co-processor in a microprocessor based system.
7. Can an input port and an output port have the same port address? Justify.
8. Why is each channel in DMA controller restricted to 16K bytes of data
9. With XTAL = 11.0592 MHz, what value should be loaded into TH1 to have
9600 baud rate?
10. How do you select the register bank in 805l microcontroller?
PART B — (5 × 16 = 80 Marks)
11. (a) (i) Write an 8085 assembly language program with flowchart for the
following: Six bytes are stored in memory locations starting at
XX50H. Add all the data bytes. Use register B to save any carry
generated while adding the data bytes. Store the sum at two
consecutive memory locations, XX70H and XX7IH. Data (H): A2,
FA, DF, E5, 98, 8B. (8)
(ii) Write a program to generate a continuous square wave with the
period of s µ 500 . Assume the system clock period is 325ns and use
bit D0 to output the square wave. (8)
(b) (i) Explain the following 8085 instructions with an example
JP, JPO, CM, RPE. DAA, XCHG. SPHL and PCHL. (8)
(ii) Draw the timing diagram for the instruction
MVI A, 32h and OUT 01h. (8)
12. (a) (i) Draw the internal block diagram of 8086 microprocessor and
(ii) Explain any eight assembler directives of 8086 microprocessor. (8)
(b) (i) Give three examples for the following 8086 microprocessor
instructions: String Instructions, Process Control Instructions,
Program Execution Transfer Instructions and Bit Manipulation
(ii) How does one define and Call Macro parameters of 8086
13. (a) (i) Draw the internal block diagram of 8087 Co-processor and explain
it with 8087 control word and status word formats. (12)
(ii) Give two examples for packed decimal data transfers and integer
data transfers of an 8087 Co-processor. (4)
(b) Draw the architecture of 8089 I/O Co-processor and explain. (16)
14. (a) Draw the block diagram of 8279 Keyboard/Display controller and explain
how to interface the Hex Key Pad and 7-segment LEDs using 8279. (16)
(b) (i) Draw the functional block diagram of 8254 timer and explain the
different modes of operation. (8)
(ii) Draw the block diagram of 8259A and explain how to program
15. (a) (i) Explain the memory structure of an 8051 Microcontroller. (8)
(ii) How does one interface a 16 × 2 LCD Display using 8051
(b) (i) Explain the on-chip timer modes of an 8051 Microcontroller. (8)
(ii) Explain how to interface an 8-bit ADC with 8051 Microcontroller.