JNTU B.Tech II Semester Examinations, MICROPROCESSORS AND MICRO CONTROLLERS, Apr/May 2008
(Electrical & Electronic Engineering)
Time: 3 hours Max Marks: 80
Answer any FIVE Questions
All Questions carry equal marks
1. Explain the arithmetic instructions of the 8086 processor. 
2. (a) Write an 8086 Assembler Program that adds two given 4-digit BCD numbers
(b) How do you pass parameters to a MACRO? [12+4]
3. Interface ADC 0808 with 8086 using 8255 ports. Use Port A of 8255 for transferring
the digital data output of ADC to the CPU and Port C fo control signals. Assume
that the analog input is present at I/P of the ADC and clock input of suitable
frequency is available to ADC. Draw the schematic and the required ALP.
4. (a) Explain the bus structure of 8086 system
(b) Explain the fundamental concepts of DRAM controller. [8+8]
5. (a) Describe the bit assignment for mode instruction format of 8251 for both
Synchronous and Asynchronous modes.
(b) Write an instruction sequence for initializing 8251 for the following combination.
i. Asynchronous mode
ii. Even parity
iii. 7 data bits
iv. 2 stop bits
v. 6400 baud rate [8+8]
6. (a) Explain the arithmetic instructions of 8051 with examples.
(b) Write 8051 program to subtract the contents of RAM location 13h from RAM
location 2Bh, put the result in RAM location 3Ch. [8+8]
7. (a) Write 8051 program as an example of interrupt call to a routine, timer 0 is
used in mode 0 to overflow and set the timer 0 interrupt flag. When the
interrupt is generated, the program vectors to the interrupt routine, resets the
timer 0 interrupt flag, stops the timer, and returns.
(b) Discuss the bit format of IP register of 8051? [8+8]
8. (a) Explain with a neat diagram how push button and LED can be connected to
(b) Mention any application of electromagnetic relay and explain how a electro-
magnetic Relay is connected to a 8051 microcontroller with diagram. [8+8]