Clock configuration

[gil_dobjanschi]

Hello,

I have a problem verifying the HCLK frequency for Nucleo-C562RE. I configure the clock to 144MHz (see image below).

When I start the application I print the HCLK frequency:

SEGGER_RTT_printf("---- MCU started at %lu[Hz] ----\n", HAL_RCC_GetHCLKFreq());

I get 48MHz:

---- MCU started at 48000000[Hz] ----

While stepping through the HAL_Init code I see that the code thinks that the clock source is LL_RCC_SYS_CLKSOURCE_STATUS_HSIDIV3 (48MHz)

uint32_t HAL_RCC_GetSYSCLKFreq(void)
{
uint32_t sysclockfreq;
uint32_t sysclk_source;

sysclk_source = LL_RCC_GetSysClkSource();
if (sysclk_source == LL_RCC_SYS_CLKSOURCE_STATUS_HSIS)
{
/* HSIS used as system clock source */
sysclockfreq = HSI_VALUE;
}
else if (sysclk_source == LL_RCC_SYS_CLKSOURCE_STATUS_HSIDIV3)
{
/* HSIS used as system clock source */
sysclockfreq = HSI_VALUE / 3U;
}

#if defined(HSE_VALUE)
else if (sysclk_source == LL_RCC_SYS_CLKSOURCE_STATUS_HSE)
{
/* HSE used as system clock source */
sysclockfreq = HSE_VALUE;
}
#endif /* HSE_VALUE */

else
{
sysclockfreq = HAL_RCC_GetPSIClockFreq();
}

return sysclockfreq;
}

However the clock diagram indicates HSIS as the source of clock for System Mux.

Help would be appreciated,

Gil

---

Edited to apply source code formatting - please see How to insert source code for future reference.

[TDK]

HSIDIV3 is the default after reset. Is it possible the clock has not been changed yet in your code? Where are you calling HAL_RCC_GetHCLKFreq in relation to clock being set? Including your IOC or code may help.

[gil_dobjanschi]

Hi TDK,

I called it before mx_system_init and after mx_system_init in the while(1) loop of the application. It always prints 48MHz. I attached the zipped ioc2 file. 

Thanks,

Gil

[STackPointer64]

Hello @gil_dobjanschi, and welcome to ST Community!

Let me check this and get back to you.

Best regards

[STackPointer64 · Accepted solution]

@gil_dobjanschi, RCC is disabled. Please enable it and test one more time.

[Saket_Om]

Hello @gil_dobjanschi

Thank you for bringing this issue to our attention.

I reported this internally.

Internal ticket number: CDM0061602.

[gil_dobjanschi]

Hi @STackPointer64,

I confirm that by simply activating RCC the clock value is now correct. Specifically it is 48MHz on startup, before  invoking mx_system_init, and 144MHz right after mx_system_init. Thank you for the help!

@Saket_Om, I'm glad I can help! 

Regards,

Gil