Unit 3

I/O INTERFACING

Memory Interfacing and I/O interfacing - Parallel communication interface – Serial communication interface – D/A and A/D Interface - Timer – Keyboard /display controller – Interrupt controller – DMA controller – Programming and applications Case studies: Traffic Light control, LED display , LCD display, Keyboard display interface and Alarm Controller.

Part A

# Question
1 State the advantage and disadvantage of parallel communication over serial communication.
2 Define the terms A/D & D/A convertor.
3 List the four display modes of 8279 keyboard and display controller
4 Name the applications of programmable interval timer.
5 Outline the interfacing in 8086.
6 Write the various modes of 8254 timer.
7 Classify the output modes used in 8279.
8 What frequency transmit clock (TxC) is required by an 8251 in order for it to transmit data at 4800 Baud with a Baud rate factor of 16?
9 Summarize the modes used by the DMA processor to transfer data.
10 What is meant by key bouncing?
11 How would you use terminal count register?
12 Draw the format of Read back Command register of 8254.
13 Mention the applications of 8251 IC chip?
14 Pointouttheadvantagesanddisadvantagesofparallel communication over serial communication.
15 Examine the features of mode 1 used in 8255?
16 Categorize the basic modes of operation of 8255?
17 State your idea on the different types of command words used in 8259?
18 Evaluate your opinion on the operating modes of 8259A?
19 Elaborate the purpose of control word written to control register in 8255.
20 Propose your idea on polling?

Part B

# Question
1 Withneatblockdiagram,explainthedescriptionand function of 8259. (13)
2 (i)Withablockdiagramdesignhow8255functionsin differentmodestoaccommodatedifferentkindofI/O devices. (5) (ii) Formulate the control word for the 8255 functions in differentmodestoaccommodatedifferentkindofI/O devices. a. To connect one input device and one output device in the strobe mode. (4) b. To connect two input devices in the strobe mode. (4)
3 (i)Discuss how tointerfaceanLCD displaywith8086 microprocessor. (7) (ii)WriteaprogramtodisplayacharacterusingLCD display. (6)
4 With neat diagram, describe the internal structure of key board and display controller. (13)
5 (i) How do you interface a keyboard and the display using keyboard/display controller? (6) (ii) Discuss about memory and I/O interfacing. (7)
6 RelatehowtointerfaceaDMAcontrollerwitha microprocessor? Assess how DMA controller transfers large amountofdatafromonememorylocationstoanother memory location. (13)
7 (i) Infer and explain the block diagram of ADC converter. (7) (ii) How is A/D converter interfaced with 8086? (6)
8 Discuss how a PIC, 8259 is interfaced to an 8086 based system. How does 8259 service an interrupt? (13)
9 (i) List the different DMA transfer modes supported by a DMA controller and explain these modes. (7) (ii) Describe the internal architectural diagram of the 8237 and explain how it functions as a DMA controller. (6)
10 Outlineandexplaintheblockdiagramof8254 Programmable Interval Timer, and also explain the various modes of operation. (13)
11 List the steps involved in interfacing an alarm controller with 8086 microprocessor and explain in detail. (13)
12 (i) Manipulate DAC converter with block diagram. (7) (ii) How is D/A converter interfaced with 8086? (6)
13 (i) Draw the block diagram of traffic light control system using 8086. (7) (ii) Write the algorithm and ALP for traffic light control system. (6)
14 Explain the operation of serial communication interface with a neat diagram. (13)