JNTU III B.Tech Supplimentary Examinations, Aug/Sep 2008

JNTU III B.Tech Supplimentary Examinations, Aug/Sep 2008


(Electrical & Electronic Engineering)


1. (a) Discuss the following interface signals of 8086 in minimum mode

i. DMA interface signals

ii. Interrupt signals

(b) Discuss the following Data Transfer instructions

i. IN

ii. MOV

iii. POP

iv. XLAT

v. LAHF.


2. (a) Write an ALP to find the smallest of a given array of 16 bit numbers? ( assume

suitable array length)

(b) Define a MACRO ”SQUARE” that calculates the Square of number.


3. (a) Explain the steps involved in the Interfacing of an I/O device

(b) Explain various methods of interfacing of I/O devices.


4. Explain various operating modes of 8259 PIC.


5. (a) Explain the pin structure of RS232C and also discuss about voltage and current specifications of RS 232C.

(b) Describe important features of 8251 USART.


6. (a) Draw the architectural diagram of 8051 microcontroller and explain in detail about each block.

(b) Explain the basic differences between a microprocessor and a microcontroller.


7. (a) Write 8051 program to generate 2 kHz square waves on pin P1.0 of port 1 using Timer interrupt.

(b) Write 8051 program to receive a serial byte through RxD.


8. Give the hardware and software details of 4 × 4 matrix keyboard interfaced to


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