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You must have learned about it. Some say it can interrupt the CPU’s sequential execution, which is the essence of microcontroller learning. Others say it helps the CPU achieve asynchronous multitasking, thereby improving CPU efficiency. Some also say it effectively manages various system resources and coordinates relationships between multiple CPUs. The knowledge I am going to talk about is something you must have heard of (not necessarily all, 
), it is interrupts.
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For embedded systems, interrupts are a mechanism for the system to immediately respond to external or internal events while executing the current task. Essentially, it is a real-time controlled interface open to the processor. ARM Cortex series CPUs have a very powerful interrupt response and processing system specifically designed to handle the above events.
Exceptions refer to errors that occur during the CPU execution process, leading to the entry into an exception handling function for processing. In overall form, interrupts and exceptions are similar; both immediately interrupt the currently executing program and enter the interrupt handling function or exception handling function. However, their roots and uses are different. Interrupts are a typical use of asynchronous programming mechanisms, which are expected to happen, while exceptions are unexpected (except for some special-purpose exceptions). An exception often means that the program has reached a state of crash.
In the Cortex-A and Cortex-R series CPUs, the one playing the important role of interrupt management is naturally the GIC. In the ARM architecture, the GIC is a key component for managing and distributing interrupt signals. It is designed to support multi-core processor systems and provide an efficient and flexible interrupt handling mechanism. With the development of the ARM architecture, the GIC has also undergone multiple version iterations, from the initial GICv1 to the latest GICv3 and GICv4. The new versions introduce several improvements, such as support for virtualized environments, allowing virtual machine monitors (VMM) to control and manage interrupts between virtual machines more precisely, and support for security extensions (TrustZone), enhancing system security.
Although there are many posts online introducing interrupts and GIC, they are relatively scattered and not systematic or comprehensive. The author is well aware of the confusion faced by beginners regarding GIC, so “The ARM GICv3 Learning Guide” is here! This book aims to provide a comprehensive reference manual for readers who are just getting started with Cortex-A and R series processors and are learning and developing GIC.
Click here->The ARM GICv3 Learning Guide
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As one of the sequels to “The ARM Cortex-R52 Learning Guide”, it is better to take them together, and I encourage interested students to pay more attention.