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BSpoe.1
BSpoe.1
Associate III
March 5, 2020
Question

[BUG] STM32WB55 Code Generation with CubeMX - HAL configuration

  • March 5, 2020
  • 3 replies
  • 1080 views

Hi,

I have some problems with the code generation in CubeMX. In the HAL_Init() are three defines checked for enabling or disabling the flash instruction cache, the flash data cache and the prefetch buffer. The default configuration says the following:

/* Configure Flash prefetch, Instruction cache, Data cache */
/* Default configuration at reset is: */
/* - Prefetch disabled */
/* - Instruction cache enabled */
/* - Data cache enabled */
#if (INSTRUCTION_CACHE_ENABLE == 0U)
 __HAL_FLASH_INSTRUCTION_CACHE_DISABLE();
#endif /* INSTRUCTION_CACHE_ENABLE */
 
#if (DATA_CACHE_ENABLE == 0U)
 __HAL_FLASH_DATA_CACHE_DISABLE();
#endif /* DATA_CACHE_ENABLE */
 
#if (PREFETCH_ENABLE != 0U)
 __HAL_FLASH_PREFETCH_BUFFER_ENABLE();
#endif /* PREFETCH_ENABLE */

I have checked this with the preconfiguration inside CubeMX. The default settings are correct. But after generation I can find an activated prefetch buffer in the HAL config file:

#define PREFETCH_ENABLE 1U
#define INSTRUCTION_CACHE_ENABLE 1U
#define DATA_CACHE_ENABLE 1U

So the prefetch buffer is enabled. I cannot change this value inside the file stm32wbxx_hal_conf.h to the correct value. When I change the value to 0 nothing happens.

What can I do to disable this without uncomment the function? Is there anything to change for the project for using the correct setting after changing the value in the HAL config file?

Thanks a lot,

Ben

This topic has been closed for replies.

3 replies

Remi QUINTIN
Remi QUINTIN
Technical Moderator
March 5, 2020

If I look carefully in the extract of the stm32wbxx_hal.c file you show, the prefetch buffer is already enabled in the start configuration set it the HAL_init function.

This activation is based on the #define PREFETCH_ENABLE            

So it is the other way round: #PREFETCH_ENABLE   is not resulting from the call to the _HAL_FLASH_PREFTECH_BUFFER_ENABLE function.

What is strange is the fact that setting PREFETCH_ENABLE  to 0 does not disable this prefetch buffer.

Did you properly rename the file stm32wbxx_hal_conf_template.h by the name other files include it which is stm32wbxx_hal_conf.h

In the end, if you really want to disable it, you can call the __HAL_FLASH_PREFETCH_BUFFER_DISABLE() macro available in the stm32wbxx_hal_flash.h file.

Could you tell me why you want to disable this prefetch buffer?

BSpoe.1
BSpoe.1Author
Associate III
March 5, 2020

I just took the generated code from CubeMX without any modification. I didn't use the template file for configuration.

When I started with the STM32WB55 controller I read something that it's not allowed to enable the prefetch buffer when using the standby mode for lowest power consumption. In my project I need the lowest consumption that is possible. And inside the example project of the p2pServer for the USB dongle it's also disabled.

Remi QUINTIN
Remi QUINTIN
Technical Moderator
March 5, 2020

​>I didn't use the template file for configuration.

You don't have to use it as such but you have to modify it with your own configuration and rename it stm32wbxx_hal_conf.h as it the name use by all the other files to include it.

Or use the __HAL_FLASH_PREFETCH_BUFFER_DISABLE() function to disable it for sure.

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