Support with fmc nand flash

[HDesa.1]

Hello,

I am running a NAND flash with STM32H7 microcontroller using FMC interface. I have referred to Using the high-density STM32F30xxD/E FMC peripheral to drive external memories datasheet for the programming purpose.

While communicating with the device, I observed that whenever I read the device for the first time I get the desired data. But when I try to access it once again using different command the data section doesn't update. I read the old read data. For example,

If I send the command to read the id for the first time then the ID is properly read. But then when I send the command to read the status register then the old data doesn't get updated.

I even tried to reset the device before each command but the device read register doesn't update. Can you help me with this? What could be the problem?

-Regards

[Tesla DeLorean]

You'll have to read the documentation more thoroughly and use a logic analyzer on the signals to ensure your understanding matches the signaling presented in reality. 

Perhaps look at EVAL board doing the same or similar.

For storage consider eMMC. 

[SofLit]

Hello,

Most probably it's due to the cache. What if you disable it? or just configure the MPU on that region: Strongly Ordered/Or Device?

[HDesa.1]

Sorry, I didn't get you exactly. Which parameter are you referring to? Can you please specify with reference to CubeIDE?

[SofLit]

In CubeMx. All is in Cortex_M7 menu:

[Tesla DeLorean]

Caching at an address level look at ConfigMPU() code examples. Not really expecting the NAND region to be cached/cacheable,

Not much in the way of part# and code to see what might be going astray..

[SofLit]

As MPU example 

void MPU_Config(void)
{
  MPU_Region_InitTypeDef MPU_InitStruct;
  
  /* Disable the MPU */
  HAL_MPU_Disable();

  /* Configure the MPU as Strongly ordered for not defined regions */
  MPU_InitStruct.Enable = MPU_REGION_ENABLE;
  MPU_InitStruct.BaseAddress = <Put your start address of the memory>;
  MPU_InitStruct.Size = <Put your region size>;
  MPU_InitStruct.AccessPermission = MPU_REGION_NO_ACCESS;
  MPU_InitStruct.IsBufferable = MPU_ACCESS_NOT_BUFFERABLE;
  MPU_InitStruct.IsCacheable = MPU_ACCESS_NOT_CACHEABLE;
  MPU_InitStruct.IsShareable = MPU_ACCESS_SHAREABLE;
  MPU_InitStruct.Number = MPU_REGION_NUMBER0;
  MPU_InitStruct.TypeExtField = MPU_TEX_LEVEL0;
  MPU_InitStruct.SubRegionDisable = 0x0;
  MPU_InitStruct.DisableExec = MPU_INSTRUCTION_ACCESS_DISABLE;

  HAL_MPU_ConfigRegion(&MPU_InitStruct);

  /* Enable the MPU */
  HAL_MPU_Enable(MPU_PRIVILEGED_DEFAULT);
}

You need to fill in:

MPU_InitStruct.BaseAddress = <Put your start address of the memory>;
MPU_InitStruct.Size = <Put your region size>;

[HDesa.1]

OK Thank you for the suggestion. I will implement this.

[HDesa.1]

Yes, I too am not sure how NAND region is going to be affected by caching but can check if this can fix my problem.

[HDesa.1]

Hi,

The method suggested by you didn't work. Is there any other which I should look for?

-Regards