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Interrupt Service Routine

A software routine that hardware invokes in response to an interrupt.

AbbreviationISR
Categoryhardware

Overview

An ISR (also called an Interrupt Handler) is a specific function in the operating system or device driver designed to handle a particular interrupt.

Execution Flow

  1. Interrupt Occurs: Hardware signals the CPU.
  2. Context Save: CPU saves its current state (registers, program counter).
  3. Jump to ISR: CPU looks up the ISR address in an Interrupt Vector Table and starts executing it.
  4. Handle Event: The ISR performs the necessary task (e.g., reading data from a buffer).
  5. Context Restore: CPU restores the saved state and resumes the original program.