C++ implementation skills for interrupt handling and exception detection functions in embedded system development

C Tips for implementing interrupt handling and exception detection functions in embedded system development

Introduction:
As embedded systems become more and more widely used, There is also an increasing need for interrupt handling and exception detection. As a high-level programming language, C is increasingly used in embedded system development. This article will introduce some techniques of C to implement interrupt handling and exception detection functions in embedded systems, and demonstrate its specific implementation methods through code examples.

1. Interrupt handling skills
For embedded systems, interrupts are a common and important event, so it is crucial to handle interrupts reasonably and efficiently. Below we will introduce several techniques for implementing interrupt handling in C.

1. Definition of interrupt handling function
   In C, you can use function objects (Function Object) to define interrupt handling functions. By defining the interrupt handling function as a class with a function call operator (operator()), interrupt handling related code can be executed in it. The following is a simple definition example of an interrupt processing function:

class InterruptHandler {
public:
    void operator()() {
        // 中断处理相关代码
    }
};

InterruptHandler interruptHandler;

2. Settings of the interrupt vector table
   In embedded systems, the interrupt vector table is used to store the address of the interrupt processing function , and implement the mapping relationship between interrupt requests and interrupt processing functions. An interrupt vector table can be implemented by defining a class that contains an array of interrupt handler function pointers. The following is a simple definition example of an interrupt vector table:

class InterruptVectorTable {
public:
    using InterruptHandlerFunc = void (*)();
    
    void setInterruptHandler(uint8_t interruptNum, InterruptHandlerFunc handler) {
        interruptHandlers[interruptNum] = handler;
    }
    
    void handleInterrupt(uint8_t interruptNum) {
        if (interruptNum < INT_NUM_MAX && interruptHandlers[interruptNum]) {
            interruptHandlers[interruptNum]();
        }
    }
    
private:
    static constexpr uint8_t INT_NUM_MAX = 16;
    InterruptHandlerFunc interruptHandlers[INT_NUM_MAX] = { nullptr };
};

InterruptVectorTable interruptVectorTable;

Using the above interrupt vector table, you can set and respond to the processing functions of each interrupt.

3. Using interrupt locking technology in C
   In order to protect the code in the critical section (Critical Section), interrupt locking technology can be used during interrupt processing. By disabling interrupts when entering a critical section, you can prevent data race problems caused by multiple interrupts accessing shared resources at the same time. The following is an example of an interrupt lock class:

class InterruptLock {
public:
    InterruptLock() {
        // 禁止中断
        disableInterrupt();
    }
    
    ~InterruptLock() {
        // 允许中断
        enableInterrupt();
    }
    
    InterruptLock(const InterruptLock&) = delete;
    InterruptLock& operator=(const InterruptLock&) = delete;
    
private:
    void disableInterrupt() {
        // 禁止中断的具体实现
    }
    
    void enableInterrupt() {
        // 允许中断的具体实现
    }
};

void criticalSection() {
    InterruptLock lock;
    // 临界区代码
}

By creating an InterruptLock object when entering the critical section, interrupt protection for the critical section can be achieved.

2. Skills in exception detection
In addition to interrupt processing, exception detection and processing are also common requirements in embedded systems. Here are some tips for implementing anomaly detection in C.

1. Definition of exception handling class
   In C, exception detection and processing can be achieved by encapsulating the exception handling function in an exception handling class. Exception handling classes can use destructors to catch exceptions and handle them accordingly. The following is a simple definition example of an exception handling class:

class ExceptionHandler {
public:
    ExceptionHandler() {
        try {
            // 可能引发异常的代码
        } catch (const std::exception& e) {
            // 异常处理的具体实现
        }
    }
};

ExceptionHandler exceptionHandler;

2. Custom exception class
   In some cases, some exception classes can be customized according to specific application requirements. to handle specific exceptions. Custom exception classes can be implemented by inheriting exception classes in the standard library (such as std::exception). The following is an example of a custom exception class:

class CustomException : public std::exception {
public:
    CustomException(const std::string& message): message(message) {}
    
    virtual const char* what() const noexcept override {
        return message.c_str();
    }
    
private:
    std::string message;
};

With a custom exception class, specific exceptions can be thrown and caught in the code.

Summary:
This article introduces some techniques for using C to implement interrupt handling and exception detection functions in embedded system development. By using methods such as function objects, interrupt vector tables, and interrupt locks, interrupts can be controlled and processed. At the same time, through exception handling classes and custom exception classes, abnormal situations can be detected and processed. These techniques can improve the reliability and stability of embedded systems and provide developers with more convenient and efficient programming methods.

Code examples: The above code examples have given corresponding sample codes in each section. Readers can make corresponding modifications and extensions according to specific application requirements and development environment.

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