STM32H7系列AXI SRAM设置不同的cache策略导致以太网初始化异常

发布于 2024-05-24 09:49:35 浏览：322 订阅该版

最近基于STM32H743处理器进行以太网移植，mpu按照art-pi配置是可以，以太网初始化正常，且可以ping通，此时AXI SRAM设置为 write-through 和 no write allocate，如下：
```c
    MPU_InitStruct.Enable			= MPU_REGION_ENABLE;
    MPU_InitStruct.BaseAddress		= 0x24000000;
    MPU_InitStruct.Size				= MPU_REGION_SIZE_512KB;
    MPU_InitStruct.AccessPermission	= MPU_REGION_FULL_ACCESS;
    MPU_InitStruct.IsBufferable		= MPU_ACCESS_BUFFERABLE;
    MPU_InitStruct.IsCacheable		= MPU_ACCESS_CACHEABLE;
    MPU_InitStruct.IsShareable		= MPU_ACCESS_NOT_SHAREABLE;
    MPU_InitStruct.Number			= MPU_REGION_NUMBER0;
    MPU_InitStruct.TypeExtField		= MPU_TEX_LEVEL0;
    MPU_InitStruct.SubRegionDisable	= 0X00;
    MPU_InitStruct.DisableExec		= MPU_INSTRUCTION_ACCESS_ENABLE;
```
尝试使用其它cache策略，出现一些奇怪的现象，表现为栈溢出或者直接进入hardfault，如下两种配置都存在问题，第一种如下， write-back 和  write allocate
```c
    MPU_InitStruct.Enable			= MPU_REGION_ENABLE;
    MPU_InitStruct.BaseAddress		= 0x24000000;
    MPU_InitStruct.Size				= MPU_REGION_SIZE_512KB;
    MPU_InitStruct.AccessPermission	= MPU_REGION_FULL_ACCESS;
    MPU_InitStruct.IsBufferable		= MPU_ACCESS_BUFFERABLE;
    MPU_InitStruct.IsCacheable		= MPU_ACCESS_CACHEABLE;
    MPU_InitStruct.IsShareable		= MPU_ACCESS_NOT_SHAREABLE;
    MPU_InitStruct.Number			= MPU_REGION_NUMBER0;
    MPU_InitStruct.TypeExtField		= MPU_TEX_LEVEL1;
    MPU_InitStruct.SubRegionDisable	= 0X00;
    MPU_InitStruct.DisableExec		= MPU_INSTRUCTION_ACCESS_ENABLE;
```
第二种如下， write-back 和  no write allocate
```c
    MPU_InitStruct.Enable			= MPU_REGION_ENABLE;
    MPU_InitStruct.BaseAddress		= 0x24000000;
    MPU_InitStruct.Size				= MPU_REGION_SIZE_512KB;
    MPU_InitStruct.AccessPermission	= MPU_REGION_FULL_ACCESS;
    MPU_InitStruct.IsBufferable		= MPU_ACCESS_BUFFERABLE;
    MPU_InitStruct.IsCacheable		= MPU_ACCESS_CACHEABLE;
    MPU_InitStruct.IsShareable		= MPU_ACCESS_NOT_SHAREABLE;
    MPU_InitStruct.Number			= MPU_REGION_NUMBER0;
    MPU_InitStruct.TypeExtField		= MPU_TEX_LEVEL0;
    MPU_InitStruct.SubRegionDisable	= 0X00;
    MPU_InitStruct.DisableExec		= MPU_INSTRUCTION_ACCESS_ENABLE;
```
有大神了解相关内容的吗？给简单介绍一些为什么会出现这种状况，似乎只要设置成MPU_ACCESS_BUFFERABLE就有问题。