Theory / Background

This section provides foundational knowledge about parallel I/O interfacing, focusing on the 8085 microprocessor and the 8255 Programmable Peripheral Interface.

Introduction To Parallel Input/output (I/o)

Parallel I/O operations allow multiple bits of data to be transmitted simultaneously between a CPU and external peripheral devices.

Intel 8255 Programmable Peripheral Interface (Ppi)

This section provides an overview of the Intel 8255 Programmable Peripheral Interface, detailing its operational modes, features, pin descriptions, and interfacing with the 8085 microprocessor.

8255 Block Diagram And Features

This section discusses the 8255 Programmable Peripheral Interface (PPI), detailing its block diagram and functional features, emphasizing its role in parallel I/O operations with the 8085 microprocessor.

8255 Pin Description (Key Pins For 8085 Interfacing)

The 8255 Programmable Peripheral Interface (PPI) plays a crucial role in interfacing the 8085 microprocessor with peripheral devices by utilizing various control and I/O pins for communication.

8255 Internal Addressing And Control Word Register

This section focuses on the internal addressing scheme and control word format specific to the 8255 Programmable Peripheral Interface (PPI), which is essential for interfacing with 8085 microprocessors.

8255 Operating Modes

The 8255 Programmable Peripheral Interface operates in various modes to configure input/output ports for different applications, including Bit Set/Reset (BSR) Mode and I/O Mode with three sub-modes.

Control Word Format For 8255

This section discusses the control word format of the 8255 Programmable Peripheral Interface (PPI) and its role in configuring input/output modes.

Interfacing 8255 With 8085

This section covers the interfacing of the 8255 Programmable Peripheral Interface (PPI) with the 8085 microprocessor, focusing on the necessary connections, control signals, and programming techniques.

Apparatus / Software Required

This section outlines the essential equipment and software needed for conducting experiments with the 8085 microprocessor and the 8255 PPI.

Procedure

This section outlines the procedure for interfacing the 8255 Programmable Peripheral Interface (PPI) with the 8085 microprocessor and conducting relevant experiments.

System Setup And 8255 Initialization

In this section, the fundamentals of setting up the 8255 Programmable Peripheral Interface (PPI) with the 8085 microprocessor are covered, focusing on the configuration of ports and initialization steps.

Program Entry And Execution

This section covers the process of entering and executing assembly programs using the 8085 microprocessor and the 8255 PPI, detailing the procedures and expected outcomes.

Observation

This section discusses the practical observation exercises to verify the operations of the 8255 PPI and control circuits using the 8085 microprocessor.

Programs To Be Executed

This section introduces practical assembly programs to interface the 8255 Programmable Peripheral Interface with the 8085 microprocessor.

Program 1: 8255 Initialization And Static Output To Port A

This section covers the initialization of the 8255 Programmable Peripheral Interface to configure its ports and output a static value to Port A.

Program 2: Blinking Leds Connected To Port A

This section covers how to configure the 8255 Programmable Peripheral Interface for blinking LEDs connected to Port A, utilizing assembly programming.

Program 3: Read Switch Inputs From Port B And Display On Port C Lower

This section describes an experiment using the 8255 Programmable Peripheral Interface to read switch inputs from Port B and display the status on Port C Lower.

Observations And Results

This section focuses on recording and interpreting outcomes from the 8255 PPI interfaced with the 8085 microprocessor, along with comparisons to expected results.

Program 1: Static Output To Port A

This section outlines the steps to configure the 8255 PPI for outputting a static byte to Port A, along with relevant programming and interfacing details.

Program 2: Blinking Leds On Port A

This section focuses on programming the 8255 PPI to blink LEDs connected to Port A using the 8085 microprocessor.

Program 3: Read Switch Inputs And Display On Port C Lower

This program demonstrates how to read switch inputs using Port B and display the status on the lower bits of Port C using the 8255 interface with the 8085 microprocessor.

Conclusion

The conclusion summarizes the operational principles of the 8255 Programmable Peripheral Interface (PPI) and its application in controlling inputs and outputs in microprocessor systems.

Viva Voce Questions

The VIVA VOCE QUESTIONS section provides a set of structured questions designed to assess understanding of the 8255 Programmable Peripheral Interface and its operation.