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The 3 players behind every interrupt: vector table, hardware, and you
- The confusion around interrupt service routines (ISR) in embedded systems can lead to bad code and unpredictable bugs.
- The three key players behind every interrupt are the interrupt vector table, hardware, and the programmer.
- The interrupt vector table is a static array of addresses that points the CPU to the address of the ISR when an interrupt occurs.
- Hardware steps in instantly when an interrupt occurs and saves essential context like registers automatically.
- The CPU jumps to the address fetched from the vector table to begin executing the ISR code.
- The compiler handles most of the saving and restoring in ISRs, including additional register saves.
- Programmers are responsible for writing logic in ISRs, such as clearing interrupt sources or toggling flags, without touching the program counter or status register directly.
- The process remains the same even for interrupts triggered by software instructions like SVC.
- Understanding the roles of the interrupt vector table, hardware, and programmer separately helps in writing efficient and precise interrupt handlers.
- Having clarity on who does what in handling interrupts is crucial for embedded engineers targeting companies like Qualcomm, Bosch, or Texas Instruments.
- This knowledge distinguishes professionals and enables them to build better relationships with processors in embedded systems.
- Separating these roles leads to leaner code, quicker debugging, and improved efficiency in embedded systems.
- Understanding the ISR process is essential for success in embedded systems development.
- Knowing the roles of the vector table, hardware, and the programmer is crucial for efficient and effective ISR programming in embedded systems.
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