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PGroe.2
PGroe.2
Associate III
November 6, 2020
Solved

How to get HCLK for LL_Init1msTick?

  • November 6, 2020
  • 3 replies
  • 1447 views

Hi

I noticed on my STM32G071.. that the "LL_mDelay(1000)" function did not produce a steady 1000ms delay if I vary the HCLK frequency (code generated by CubeIDE)...

I did not have this problem with other MCUs code generated, it worked out of the box (F103/F407).

Then I stumbled upon the "LL_Init1msTick(uint32_t HCLKFrequency)" function which seemed to have solved my problem.

But what is the proper (dynamic) way to get the HCLK frequency for the function?

I currently use this in my main.c:

 /* USER CODE BEGIN SysInit */
 LL_Init1msTick(RCC_GetHCLKClockFreq(RCC_GetSystemClockFreq()));
 /* USER CODE END SysInit */

This seems to pass a valid HCLK to the function. But CubeIDE tells me a warning that:

../Core/Src/main.c: In function 'main':
../Core/Src/main.c:85:18: warning: implicit declaration of function 'RCC_GetHCLKClockFreq'; did you mean 'LL_RCC_GetCECClockFreq'? [-Wimplicit-function-declaration]
 LL_Init1msTick(RCC_GetHCLKClockFreq(RCC_GetSystemClockFreq()));
 ^~~~~~~~~~~~~~~~~~~~
 LL_RCC_GetCECClockFreq
../Core/Src/main.c:85:39: warning: implicit declaration of function 'RCC_GetSystemClockFreq'; did you mean 'LL_RCC_GetSystemClocksFreq'? [-Wimplicit-function-declaration]
 LL_Init1msTick(RCC_GetHCLKClockFreq(RCC_GetSystemClockFreq()));
 ^~~~~~~~~~~~~~~~~~~~~~
 LL_RCC_GetSystemClocksFreq

0693W000005AevWQAS.pngWhats the problem here?

This topic has been closed for replies.
Best answer by TDK

The proper LL way is to call LL_RCC_GetSystemClocksFreq and use the HCLK value it returns. RCC_GetHCLKClockFreq is a private function, for whatever reason.

You could also just put the function declaration for RCC_GetHCLKClockFreq in your header and use it directly, but using a private function is probably not the proper way.

3 replies

TDK
TDKBest answer
November 6, 2020

The proper LL way is to call LL_RCC_GetSystemClocksFreq and use the HCLK value it returns. RCC_GetHCLKClockFreq is a private function, for whatever reason.

You could also just put the function declaration for RCC_GetHCLKClockFreq in your header and use it directly, but using a private function is probably not the proper way.

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PGroe.2
PGroe.2Author
Associate III
November 6, 2020

Thanks, already figured it out :)

 LL_RCC_ClocksTypeDef RCC_CLOCKS;
 LL_RCC_GetSystemClocksFreq(&RCC_CLOCKS);
 LL_Init1msTick(RCC_CLOCKS.HCLK_Frequency);

Piranha
Piranha
Principal III
November 6, 2020

https://github.com/STMicroelectronics/STM32CubeG0/blob/5114d9a57d8a450082fc8cafe4fe34d3610d0cef/Drivers/STM32G0xx_HAL_Driver/Src/stm32g0xx_ll_rcc.c#L89

A "private" functions, which are not private - not declared as static... There wouldn't be this misunderstanding if those "private" functions would actually be private. The HAL team's incompetence level is top notch!

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