Rashtrasant Tukadoji Maharaj Nagpur University 2009 B.E Electrical Engineering Winter , Faculty of Engineering and Technology, - Question Paper

part A

1. (a) Write a short note on Linear decoding and partial decoding. provide schematic of every.
(b) What is significance of ALE pin? discuss the concept of multiplexing and demultiplexing the address bus and data bus of 8085 microprocessor with proper schematic.

2. (a) discuss the meaning of subsequent indtructions of 8085 microprocessor:
(i) DAD H
(ii) XTHL
(iii) RAR
(iv) CMP B.
(b) provided an 8085 system with register and memory contents as provided beneath. Show how the instructions listed beneath will affect these contents. Parts 1, 2, three are independent of every other:
A=73H, B=4AH, C=5FH, D= 3CH, E=A7H, H=20H, L=20H.

3. (a) Write a program for BCD addition of 2 eight bit numbers. discuss the special instruction used for BCD addition in brief.
(b) Draw the flag structure of 8085 and discuss it.
(c) discuss the significance of PSW.

4. (a) Draw and discuss the timing diagram of CALL 4000H instruction.
(b) discuss the subsequent pins of 8085:
(i) X1 and X2
(ii) READY
(iii) TRAP

5. (a) Why is stack memory required? discuss in brief various instructions available in 8085 that use stack memory. provide suitable examples.
(b) Interface the 4K*8 RAM and 4K*8 ROM with 8085. presume a suitable address.

part B

6. Draw a neat diagram for interfacing of eight numbers of seven segment displays in multiplexed manner to 8085 processor. Show complete hardware and mention IC details relevant for interfacing. Draw a flow chart and write software to flash the message after every two seconds.

7. (a) Write a program to generate a square wave with a period of 400 micro-seconds using SOD pin of a microprocessor having 2MHz clock frequency.
(b) Mention the interrupt pins of 8085, its priorities, kind of input pulse, their vector locations, state whether maskable and non-maskable.

8. (a) discuss 8253 system interface with the help of block diagram from address 40 H.
(b) What is the difference ranging from memory mapped I/O and I/O mapped I/O?

9. (a) Design an interface of DAC 0808 with 8085 using 8255 parts such that CWR addressed43H. Also write a program to generate sawtooth of amplitude +10V and time period of 4m sec.
(b) discuss the control word format for I/O mode and BSR mode in 8255 PPI.

10. Write short notes on any 3 of the following:
(a) Bus contention
(b) Interfacing of ADC with 8085 using 8255.
(c) Handshaking concept
(d) Assembler directives
(e) Interfacing 4*4 keyboard to microprocessor
(f) Methods, Formats and Modes of Data transfer.

Earning:   Approval pending.