STM32N6 ICache issue

[Chirag_Shah]

Hello everyone!

I am using stm32n6570-dk. My project has only FSBL and was generated using STM32CubeMX. I was able to run it in debug mode without issues. The code does not execute when flashed to external flash memory. I had to comment out "MX_ICACHE_Init();" for the code to run from external memory. 

I thought there may be a configuration issue from my side. So I ran the "Starter project" provided by STM located at "STM32CubeN6\Projects\STM32N6570-DK\Templates_Board". This code also runs fine in debug mode. It does not work when flashed to external memory without commenting out "MX_ICACHE_Init();".

I expect the example code to work without modifications. 

 

I figured out that the program does not reach the error handler and gets stuck in HAL_ICACHE_ConfigAssociativityMode(). This is when flashed to external memory.

if (HAL_ICACHE_ConfigAssociativityMode(ICACHE_1WAY) != HAL_OK)

{

Error_Handler();

}
Within HAL_ICACHE_ConfigAssociativityMode() it gets stuck in READ_BIT(ICACHE->CR, ICACHE_CR_EN) 

 

In debug mode I tried executing 

uint32_t HAL_ICACHE_IsEnabled(void)

{

return ((READ_BIT(ICACHE->CR, ICACHE_CR_EN) != 0U) ? 1UL : 0UL);

}

after which the program stops responding.

I tried

if (HAL_ICACHE_Invalidate() != HAL_OK)

{

Error_Handler();

}

inside MX_ICACHE_Init which does not help. This is when flashed to external memory.

The program does not reach the Error_Handler() and stops at HAL_ICACHE_Invalidate().

My plan is to first get the ICache working on the example code, then I can apply the same fix to my project.

Any help is appreciated. Thanks!

 

[Saket_Om]

Hello @Chirag_Shah 

I cannot see MX_ICACHE_Init(); in the example "STM32CubeN6\Projects\STM32N6570-DK\Templates_Board"

[Chirag_Shah]

Hi @Saket_Om ,

You are correct.

ST released v1.3.0 for STM32CubeN6 MCU Firmware Package 3 days ago (23rd Jan 2026), which does not have MX_ICACHE_Init();. As expected this code runs properly after building and loading to the external flash.

v1.3.0

v1.2.0 does have MX_ICACHE_Init();

 

Nevertheless the question remains; Why am I unable to use v1.2.0 with MX_ICACHE_Init()?
I feel it may have something to do with the security/RIF settings but I have not been able to fix it so far.
Answer to this question will help me implement the same in my own project. 

Thank you Saket for looking into it!

 

 

[Saket_Om]

Hello @Chirag_Shah 

Thank you for bringing this issue to our attention.

I reported this internally.

Internal ticket number: 225931 (This is an internal tracking number and is not accessible or usable by customers).