NVIC_SystemReset() 卡在 while 循环中 (STM32F302VB) [英] NVIC_SystemReset() stuck in while loop (STM32F302VB)

问题描述

我目前正在 STM32F302VB 上进行开发，我需要执行软件重置.在我之前的所有项目(使用 STM32F427 和 STM32F030C8)中，我一直成功地使用了 NVIC_SystemReset() 函数.但由于某种原因，它不适用于该芯片.实现在CMSIS core_cm4.h中，如下:

I'm currently developing on a STM32F302VB and I need to perform a software reset. On all my previous projects (with STM32F427 and STM32F030C8), I've always used the NVIC_SystemReset() function successfully. But for some reason it won't work with this chip. The implementation is in CMSIS core_cm4.h and is as follows:

__STATIC_INLINE void NVIC_SystemReset(void)
{
  __DSB(); /* Ensure all outstanding memory accesses included buffered write are completed before reset */
  SCB->AIRCR  = ((0x5FA << SCB_AIRCR_VECTKEY_Pos)      |
             (SCB->AIRCR & SCB_AIRCR_PRIGROUP_Msk) |
             SCB_AIRCR_SYSRESETREQ_Msk);                   /* Keep priority group unchanged */
  __DSB();                                                     /* Ensure completion of memory access */
  while(1);                                                    /* wait until reset */
}

该函数被调用并执行了所有指令，但它卡在了while循环中，并且从未发生过reset.然后我必须通过 JTAG 将其重置以使其退出该状态.

The function is called and all instructions are executed, but it gets stuck in the while loop, and reset never happens. I then have to reset it via JTAG to get it out of that state.

我查看了编程手册，实现似乎很好(这并不奇怪，因为它在 F4 和 F0 上运行完美).

I checked the programming manual and the implementation seems fine (not surprising since it works perfectly on F4 and F0).

我真的不知道可能是什么问题，有人知道发生了什么吗?

I really don't know what the problem might be, does someone have an idea what's going on?

该功能仍然无法正常工作，但作为一种解决方法，在该功能卡住后，我将 nRST 引脚拉低，然后再拉高.这很丑陋，但它现在有效.不过，我更愿意用软件来做这一切.

The function is still not working but as a workaround, after the function gets stuck, I pull down the nRST pin and then up. It's ugly, but it works for now. I would rather do it all in software though.

推荐答案

Tony K 在他的评论中是正确的，由于布线错误，nRST 引脚确实被外部拉高了.

Tony K was right in his comment, the nRST pin was indeed being pulled high externally, because of a routing mistake.

与我的想法相反，即使在软件重置中也会考虑 nRST 引脚:参考手册说:[重置] 源作用于 NRST 引脚，并且在延迟阶段始终保持低电平"，所以我应该知道！

And contrary to what I thought, the nRST pin is taken into account even in a software reset: the reference manual says: "[Reset] sources act on the NRST pin and it is always kept low during the delay phase", so I should have known!

去掉上拉就成功了，NVIC_SystemReset() 函数现在可以正常工作了！

Removing the pull-up did the trick, the NVIC_SystemReset() function now works as expected!

非常感谢！

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