Microcontroller Lab | EXPERIMENT NO. 5 TITLE: Interrupt Handling and Timer Interfacing (8085/8086 Microprocessors with 8253/8254 Timer) by Prakhar Chauhan | Learn Smarter
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EXPERIMENT NO. 5 TITLE: Interrupt Handling and Timer Interfacing (8085/8086 Microprocessors with 8253/8254 Timer)

This chapter introduces the fundamental concepts of interrupt handling and timer interfacing in microprocessors. It covers the types of interrupts, their purposes, and the process of handling hardware interrupts, specifically focusing on the 8085 and 8086 microprocessors. Additionally, it describes the 8253/8254 Programmable Interval Timer, its modes of operation, and practical applications for generating time delays and square waves.

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Sections

  • 1

    Theory / Background

    This section provides an overview of interrupts in microprocessors, explaining their importance, types, and handling mechanisms, with specific focus on the 8085 and 8086 architectures.

    Learning Practice

  • 1.1

    Concepts Of Interrupts

    This section covers the fundamental concepts of interrupts in microprocessors, their types, purposes, and the process flow of handling interrupts.

    Learning Practice

  • 1.2

    Interrupt Handling In 8085 Microprocessor (Part A)

    This section covers the interrupt handling mechanisms in the 8085 microprocessor, including hardware and software interrupts, and the role of various interrupt service routines.

    Learning Practice

  • 1.3

    Interrupt Handling In 8086 Microprocessor (Part A - Overview)

    This section provides an overview of interrupt handling in the 8086 microprocessor, detailing its structure, types, and the roles of hardware and software interrupts.

    Learning Practice

  • 1.4

    Timer Interfacing With 8253/8254 (Part B)

    This section discusses the interfacing of the 8253/8254 timer with microprocessors and the various configurations and modes available for generating time delays and square waves.

    Learning Practice

  • 1.4.1

    8254 Pin Description (Key Pins)

    This section provides an overview of the key pins of the 8254 timer, detailing their functions and how they facilitate communication with microprocessors.

    Learning Practice

  • 1.4.2

    8254 Internal Addressing

    The section discusses the internal addressing of the 8254 Programmable Interval Timer, detailing its control word format, I/O addressing, and operation modes.

    Learning Practice

  • 1.4.3

    8254 Control Word Format

    The 8254 Control Word Format outlines how to program the 8254 timer by writing an 8-bit control word to its Control Word Register, specifying counter selection, read/write control, mode selection, and counting mode.

    Learning Practice

  • 1.4.4

    8254 Operating Modes (Relevant To Experiment)

    This section details the various operating modes of the 8254 programmable interval timer, particularly focusing on Mode 0, Mode 2, and Mode 3, including their operations and applications in generating precise time delays and waveforms.

    Learning Practice

  • 2

    Apparatus / Software Required

    This section outlines the necessary hardware and software requirements for conducting Experiment No. 5 on interrupt handling and timer interfacing with microprocessors.

    Learning Practice

  • 3

    Procedure

    This section outlines the procedure for conducting Experiment No. 5, which includes understanding interrupt handling in 8085/8086 microprocessors and interfacing the 8254 timer.

    Learning Practice

  • 3.1

    Part A: Interrupt Handling (8085)

    This section covers interrupt handling in the 8085 microprocessor, including the types of interrupts, their purposes, and how to manage them effectively.

    Learning Practice

  • 3.2

    Part B: Timer Interfacing (8254)

    This section covers the interfacing and operational principles of the 8254 Programmable Interval Timer (PIT), highlighting its features, usage considerations, and programming methods.

    Learning Practice

  • 4

    Programs To Be Executed

    This section elaborates on the programs required for understanding interrupt handling and timer interfacing in microprocessors, focusing on 8085 and 8086 architectures.

    Learning Practice

  • 4.1

    Part A: Interrupt Handling (8085)

    This section covers the fundamental concepts of interrupt mechanisms in the 8085 microprocessor, including the types of interrupts, the interrupt handling process, and specifics regarding hardware interrupts.

    Learning Practice

  • 4.2

    Part B: Timer Interfacing (8254)

    This section covers the interfacing of the 8254 timer with microprocessors to generate precise time delays and square wave signals, explaining its operational modes and programming techniques.

    Learning Practice

  • 4.2.1

    Program B.1: Time Delay Using 8254 (Mode 0)

    This section covers the use of the 8254 timer in Mode 0 to generate specific time delays in a microprocessor system.

    Learning Practice

  • 4.2.2

    Program B.2: Generate A Square Wave Using 8254 (Mode 3)

    This section explains how to use the 8254 Programmable Interval Timer to generate a square wave in Mode 3.

    Learning Practice

  • 5

    Observations And Results

    This section provides a detailed analysis of the observations and results from experiments involving interrupt handling and timer interfacing in microprocessors.

    Learning Practice

  • 5.1

    Part A: Interrupt Handling (Rst 7.5)

    This section covers the interrupt handling mechanism in microprocessors, focusing on the RST 7.5 hardware interrupt in the 8085 microprocessor.

    Learning Practice

  • 5.2

    Part B: Timer Interfacing (8254)

    This section covers the fundamentals of timer interfacing with the 8254 Programmable Interval Timer, detailing its features, operations, and programming.

    Learning Practice

  • 5.2.1

    Program B.1: Time Delay (Mode 0)

    This section covers the use of the 8254 timer in Mode 0 to generate precise time delays in microprocessor systems.

    Learning Practice

  • 5.2.2

    Program B.2: Square Wave Generation (Mode 3)

    This section details how to generate square waves using the 8254 timer in Mode 3 with a specific focus on configuration steps and practical applications.

    Learning Practice

  • 6

    Conclusion

    The section summarizes the importance of interrupt handling in microprocessors and the utilization of the 8254 timer for generating precise delays and square waves.

    Learning Practice

  • 7

    Viva Voce Questions

    This section provides a set of viva voce questions related to interrupt handling and timer interfacing in microprocessors.

    Learning Practice

References

Untitled document (13).pdf

Class Notes

Memorization

What we have learnt

  • Interrupts are signals indi...
  • The 8085 microprocessor han...
  • The 8254 timer can be progr...

Final Test

Revision Tests