c - RAM 测试逐步通过，但在运行时失败

Question

我正在做的项目需要在程序运行前测试一个dsPIC30F芯片的数据存储器。由于行业要求，我们不能使用 C 必须提供的任何预定义库。也就是说，这是我测试 RAM 的方法:

Step 1 - Write the word 0xAAAA to a specific location in memory (defined by a LoopIndex added to the START_OF_RAM address)

Step 2 - increment LoopIndex

Step 3 - Repeat Steps 1-2 until LoopIndex + START_OF_RAM >= END_OF_RAM

Step 4 - Reset LoopIndex = 0

Step 5 - Read memory at LoopIndex+START_OF_RAM

Step 6 - If memory = 0xAAAA, continue, else throw RAM_FAULT_HANDLER

Step 7 - increment LoopIndex

Step 8 - Repeat Step 5 - 7 until LoopIndex + START_OF_RAM >= END_OF_RAM

现在，奇怪的是我可以单步执行代码，没问题。只要我的小指可以按 F8，它就会慢慢地遍历每个内存地址，但是当我尝试在第 4 步设置断点时，它会无缘无故地抛出一个随机的通用中断处理程序。我想过可能是因为我使用的for()可能超过了END_OF_RAM，但是我已经改变了条件的界限，它仍然不喜欢运行。

任何见解都会有所帮助。

void PerformRAMTest()
{

    // Locals
    uint32_t LoopIndex = 0;
    uint16_t *AddressUnderTest;
    uint32_t RAMvar = 0;
    uint16_t i = 0;

    // Loop through RAM and write the first pattern (0xAA) - from the beginning to the first RESERVED block
    for(LoopIndex = 0x0000; LoopIndex < C_RAM_END_ADDRESS; LoopIndex+= 2)
    {

        AddressUnderTest = (uint32_t*)(C_RAM_START_ADDRESS + LoopIndex);

        *AddressUnderTest = 0xAAAA;


    }// end for

    for(LoopIndex = 0x0000; LoopIndex < C_RAM_END_ADDRESS; LoopIndex += 2)
    {
        AddressUnderTest = (uint32_t*)(C_RAM_START_ADDRESS + LoopIndex);

        if(*AddressUnderTest != 0xAAAA)
            {
                // If what was read does not equal what was written, log the
                // RAM fault in NVM and call the RAMFaultHandler()
                RAMFaultHandler();
            }// end if
    }

    // Loop through RAM and write then verify the second pattern (0x55)
    // - from the beginning to the first RESERVED block
//    for(LoopIndex = C_RAM_START_ADDRESS; LoopIndex < C_RAM_END_ADDRESS; LoopIndex++)
//    {
//        AddressUnderTest = (uint32_t*)(C_RAM_START_ADDRESS + LoopIndex);
//        *AddressUnderTest = 0x5555;
//        if(*AddressUnderTest != 0x5555)
//        {
//            // If what was read does not equal what was written, log the
//            // RAM fault in NVM and call the RAMFaultHandler()
//            RAMFaultHandler();
//        }
//    }

}// end PerformRAMTest

你可以看到第二遍测试写入了0x55。这是给我的原始实现，但它从未奏效(至少就调试/运行而言；这种写入方法遇到了相同的随机中断，然后在继续之前立即读取相同的地址)

更新:在几次 Clean&Builds 之后，代码现在将运行直到它到达堆栈指针 (WREG15)，跳过，然后出错。这是相关代码的新示例:

if(AddressUnderTest >= &SPLIMIT && AddressUnderTest <= SPLIMIT)
    {
        // if true, set the Loop Index to point to the end of the stack
        LoopIndex = (uint16_t)SPLIMIT;
    }
    else if(AddressUnderTest == &SPLIMIT) // checkint to see if AddressUnderTest points directly to the stack [This works while the previous >= &SPLIMIT does not. It will increment into the stack, update, THEN say "oops, I just hit the stack" and error out.]
    {
        LoopIndex = &SPLIMIT;
    }
    else
    {
        *AddressUnderTest = 0xAAAA;
    }

Answer 1

我想你真的想要(C_RAM_START_ADDRESS + LoopIndex) < C_RAM_END_ADDRESS作为你的循环条件。当前，您正在从 C_RAM_START_ADDRESS 循环至 C_RAM_START_ADDRESS + C_RAM_END_ADDRESS我假设是在写入 RAM 末尾之后。

您还应该真正将重复的代码分解为一个单独的函数，该函数将测试模式作为参数 (DRY)。