试图读取STM32F4上未对齐的DMA寄存器地址时出现硬故障

我猜想CPU和DMA控制器之间的总线只允许32位访问操作。

您可以从硬故障中断内部打印(或转储到内存)。

例如:

void HardFault_Handler(unsigned int* hardfault_args)
{
    printf("R0    = 0x%.8X\r\n",hardfault_args[0]);         
    printf("R1    = 0x%.8X\r\n",hardfault_args[1]);         
    printf("R2    = 0x%.8X\r\n",hardfault_args[2]);         
    printf("R3    = 0x%.8X\r\n",hardfault_args[3]);         
    printf("R12   = 0x%.8X\r\n",hardfault_args[4]);         
    printf("LR    = 0x%.8X\r\n",hardfault_args[5]);         
    printf("PC    = 0x%.8X\r\n",hardfault_args[6]);         
    printf("PSR   = 0x%.8X\r\n",hardfault_args[7]);         
    printf("BFAR  = 0x%.8X\r\n",*(unsigned int*)0xE000ED38);
    printf("CFSR  = 0x%.8X\r\n",*(unsigned int*)0xE000ED28);
    printf("HFSR  = 0x%.8X\r\n",*(unsigned int*)0xE000ED2C);
    printf("DFSR  = 0x%.8X\r\n",*(unsigned int*)0xE000ED30);
    printf("AFSR  = 0x%.8X\r\n",*(unsigned int*)0xE000ED3C);
    printf("SHCSR = 0x%.8X\r\n",SCB->SHCSR);                
    while (1);
}

或者,您可以简单地在硬故障中断内停止,并查看IDE中的那些寄存器。。。

从STM32F4数据表:

The MPU attributes don't affect DMA data accesses to the memory/peripherals address
spaces. therefore, in order to protect the memory areas against inadvertent DMA accesses,
the MPU must control the SW/CPU access to the DMA registers.

因此,似乎有一些限制,特别是关于访问DMA寄存器。

根据PaulR的评论,OP扩展了答案:

文件挖掘证实,原因是DMA AHB从机编程接口的限制。

在DM00031020章中 10.2 DMA主要功能 它清楚地写着“仅支持32位访问的AHB从编程接口”。相反,例如,DMA2D支持8位、16位和32位访问,因此可以逐字节访问,不会导致总线故障。