Architecture of a System

Architecture of 8259

Last Updated : 26 Jun, 2024

The 8259 is a programmable interrupt controller which has a unique style. Some certain interrupt conditions regulate the interrupt levels as well. These interrupt levels are also known as the edge-triggered interrupt where the masking process is related to the individual interrupt bits with 64 pins. In this article, we are going to discuss the Architecture of 8259 in detail.

Table of Content

What Is 8259?
Architecture Diagram
Block Description
Application

What is 8259?

The Programmable Interrupt Controller 8259 is developed by Intel. It is used to manage and control hardware interrupts in a computer system. It enables the CPU to handle multiple interrupt requests efficiently. The 8259 is used in systems based on Intel 8086/8088 microprocessors, among others, to prioritize and manage interrupt signals from various peripheral devices.

Architecture Diagram of 8259

Here is the block diagram of 8259 as mentioned below.

267 — Architecture of 8259

Architecture of 8259 - Block Description

Now we are going to discuss the Block Architecture of 8259 as mentioned below.

Block Components	Descriptions
Data Bus Buffer	The Data Bus Buffer always interfaces with the system data bus. It allows the data to transfer between the CPU and the 8259. It is a bi-directional process. The process helps the command to perform the read and write operations by interrupting the vectors.
Read/Write Logic	The read/Write Logic block controls the operations related to the reading and writing processes. These processes are related to the internal registers of the 8259. This block interprets the control signaling related to the CPU.
Control Logic	The Control Logic block is the nodal system of the 8259. It decodes the commands of the CPU and also regulates the information flow in the 8259. Three different processes are related to the Control Logic as mentioned below. Interrupt Request Register (IRR) latches the incoming interrupt requests. The In-Service Register (ISR) maintains the track record of the performed interruptions. Interrupt Mask Register (IMR) performs in favor of the specific interrupt lines which can be enabled or disabled.
Priority Resolver	Priority Resolver works on the priority module. It filters the priority of the incoming interrupts and related requests which can be fixed or rotating.
Interrupt Request Lines (IR0-IR7)	These lines are the mediator through which the external devices send the interrupt requests to the 8259 through a specific interrupt vector.
Interrupt Control Lines	Interrupt Control Lines are divided into two parts i.e. INT and INTA. INT is an output line that picks the interrupt request which needs to be serviced. On the other side, INTA prompts the 8259 to send the interrupt to an appropriate vector.
Cascade Buffer/Comparator	Cascade Buffer/Comparator allows to connection of the multiple 8259 in a cascade formation to handle more than 8 interrupt lines at the same time.
Registers	Interrupt Request Register (IRR): It holds the interrupt requests from the peripheral devices. It keeps track of which interrupts are pending. In-Service Register (ISR): It tracks the interrupts which are currently being serviced. Once an interrupt is acknowledged and its service routine begins execution, it is marked in the ISR. Interrupt Mask Register (IMR): Used to enable or disable specific interrupt requests.

Application of 8259

Here are the applications of 8259 as mentioned below.

Keyboard input management.
Mouse input handling.
Serial communication.
Parallel port management.
Disk drive operations.
Timer interrupts.
Network interface control.
Sound card operations.
USB device management.
System error handling.

Conclusion

8259 microprocessor is a programmable interrupt controller which has a unique style. It can handle multiple interrupts efficiently. It can be programmed to perform different priority schemes. It is also compatible with a wide range of microprocessors.

People Also Read

Architecture of a System

dasrudra0710

Improve

Article Tags :

Similar Reads

Architecture of a System

Architecture is a critical aspect of designing a system, as it sets the foundation for how the system will function and be built. It is the process of making high-level decisions about the organization of a system, including the selection of hardware and software components, the design of interfaces

PowerPC Architecture

PowerPC Architecture are microprocessor for personal computers. PowerPC is a RISC (Reduced Instruction Set Computer) architecture which are very powerful and low-cost microprocessors. RISC architecture tries to keep the processor as busy as possible. Design features of PowerPC are as follows: Broad

Architecture of 8085 microprocessor

A microprocessor is fabricated on a single integrated circuit (IC) or chip that is used as a central processing unit (CPU).The 8085 microprocessor is an 8-bit microprocessor that was developed by Intel in the mid-1970s. It was widely used in the early days of personal computing and was a popular cho

8051 MicroController Architecture

For many years, the 8051 microcontroller architecture is vital and important component in embedded systems design due to its common use. Its strong architecture and multiple uses in a variety of industries from consumer electronics to industrial automation are the main causes of its appeal.What is 8

Xilinx FPGA Architecture

FPGA, which stands for field-programmable gate array, can be used to solve any computable issue. It is an integrated circuit that may be customized after manufacturing by a client or a designer. To be more specific, FPGAs (Field Programmable Gate Arrays) are semiconductor devices that consist of a m

UltraSPARC Architecture

UltraSPARC Architecture belongs to the SPARC (Scalable Processor Architecture) family of processors. This architecture is suitable for wide range of microcomputers and supercomputers. UltraSPARC is example of RISC (Reduced Instruction Set Computer). UltraSPARC architecture: Memory: Memory consists o

Registers used in 8259

The 8259 is a programmable interrupt controller. It was designed to manage multiple interrupt requests from various peripheral devices in a computer system. 8259 is a programmable interrupt controller which has a unique style. Some certain interrupt conditions regulate the interrupt levels as well.

Block Diagram of 8259 Microprocessor

The 8259 Programmable Interrupt Controller (PIC) is a microprocessor peripheral used to manage interrupts in a system. It helps in handling multiple interrupt requests (IRQs) and sending the interrupt service routines (ISRs) to the microprocessor.The 8259 Microprocessor refers to the Intel 8259 Prog

8259 PIC Microcontroller

Intel 8259 is a Programmable Interrupt Controller (PIC). There are 5 hardware interrupts and 2 hardware interrupts in Intel 8085 and Intel 8086 microprocessors respectively. But by connecting Intel 8259 with these microprocessors, we can increase their interrupt handling capability. Intel 8259 combi

Hexagonal Architecture - System Design

Hexagonal Architecture, also known as Ports and Adapters Architecture, is a design pattern used in system development. It focuses on making software flexible and adaptable by separating the core logic from external dependencies, like databases or user interfaces. In this approach, the core system co