SYSTEM

Functions
void	LL_SetSystemCoreClock (uint32_t CPU_Frequency)
	This function sets directly SystemCoreClock CMSIS variable.
ErrorStatus	LL_PLL_ConfigSystemClock_HSI (LL_UTILS_PLLInitTypeDef *UTILS_PLLInitStruct, LL_UTILS_ClkInitTypeDef *UTILS_ClkInitStruct)
	This function configures system clock at maximum frequency with HSI as clock source of the PLL.
ErrorStatus	LL_PLL_ConfigSystemClock_HSE (uint32_t HSEFrequency, uint32_t HSEBypass, LL_UTILS_PLLInitTypeDef *UTILS_PLLInitStruct, LL_UTILS_ClkInitTypeDef *UTILS_ClkInitStruct)
	This function configures system clock with HSE as clock source of the PLL.
ErrorStatus	LL_SetFlashLatency (uint32_t HCLK_Frequency)
	Update number of Flash wait states in line with new frequency and current voltage range.

Detailed Description

Function Documentation

LL_PLL_ConfigSystemClock_HSE()

ErrorStatus LL_PLL_ConfigSystemClock_HSE	(	uint32_t	HSEFrequency,
		uint32_t	HSEBypass,
		LL_UTILS_PLLInitTypeDef *	UTILS_PLLInitStruct,
		LL_UTILS_ClkInitTypeDef *	UTILS_ClkInitStruct
	)

This function configures system clock with HSE as clock source of the PLL.

Note

The application need to ensure that PLL is disabled.

Function is based on the following formula:

• PLL output frequency = (((HSE frequency / PLLM) * PLLN) / PLLP)
• PLLM: ensure that the VCO input frequency ranges from 0.95 to 2.10 MHz (PLLVCO_input = HSE frequency / PLLM)
• PLLN: ensure that the VCO output frequency is between 150 and 836 MHz or 128 to 560 MHz(***) (PLLVCO_output = PLLVCO_input * PLLN)
• PLLP: ensure that max frequency at 550000000 Hz(*), 480000000 Hz(**) or 280000000 Hz(***) is reached (PLLVCO_output / PLLP)

Parameters

HSEFrequency	Value between Min_Data = 4000000 and Max_Data = 48000000
HSEBypass	This parameter can be one of the following values: LL_UTILS_HSEBYPASS_ON LL_UTILS_HSEBYPASS_OFF
UTILS_PLLInitStruct	pointer to a LL_UTILS_PLLInitTypeDef structure that contains the configuration information for the PLL.
UTILS_ClkInitStruct	pointer to a LL_UTILS_ClkInitTypeDef structure that contains the configuration information for the BUS prescalers.

Return values

An	ErrorStatus enumeration value: SUCCESS: Max frequency configuration done ERROR: Max frequency configuration not done

(*) : For stm32h72xxx and stm32h73xxx family lines and requires to enable the CPU_FREQ_BOOST flash option byte, 520MHZ otherwise. (**) : For stm32h74xxx and stm32h75xxx family lines and requires the board to be connected on LDO regulator not SMPS, 400MHZ otherwise. (***): For stm32h7a3xx, stm32h7b3xx and stm32h7b0xx family lines.

LL_PLL_ConfigSystemClock_HSI()

ErrorStatus LL_PLL_ConfigSystemClock_HSI	(	LL_UTILS_PLLInitTypeDef *	UTILS_PLLInitStruct,
		LL_UTILS_ClkInitTypeDef *	UTILS_ClkInitStruct
	)

This function configures system clock at maximum frequency with HSI as clock source of the PLL.

Note

The application need to ensure that PLL is disabled.

Function is based on the following formula:

• PLL output frequency = (((HSI frequency / PLLM) * PLLN) / PLLP)
• PLLM: ensure that the VCO input frequency ranges from 1 to 16 MHz (PLLVCO_input = HSI frequency / PLLM)
• PLLN: ensure that the VCO output frequency is between 150 and 836 MHz or 128 to 560 MHz(***) (PLLVCO_output = PLLVCO_input * PLLN)
• PLLP: ensure that max frequency at 550000000 Hz(*), 480000000 Hz(**) or 280000000 Hz(***) is reach (PLLVCO_output / PLLP)

Parameters

UTILS_PLLInitStruct	pointer to a LL_UTILS_PLLInitTypeDef structure that contains the configuration information for the PLL.
UTILS_ClkInitStruct	pointer to a LL_UTILS_ClkInitTypeDef structure that contains the configuration information for the BUS prescalers.

Return values

An	ErrorStatus enumeration value: SUCCESS: Max frequency configuration done ERROR: Max frequency configuration not done

(*) : For stm32h72xxx and stm32h73xxx family lines and requires to enable the CPU_FREQ_BOOST flash option byte, 520MHZ otherwise. (**) : For stm32h74xxx and stm32h75xxx family lines and requires the board to be connected on LDO regulator not SMPS, 400MHZ otherwise. (***): For stm32h7a3xx, stm32h7b3xx and stm32h7b0xx family lines.

LL_SetFlashLatency()

ErrorStatus LL_SetFlashLatency

(

uint32_t

HCLK_Frequency

)

Update number of Flash wait states in line with new frequency and current voltage range.

Parameters

HCLK_Frequency

HCLK frequency

Return values

An	ErrorStatus enumeration value: SUCCESS: Latency has been modified ERROR: Latency cannot be modified

LL_SetSystemCoreClock()

void LL_SetSystemCoreClock

(

uint32_t

CPU_Frequency

)

This function sets directly SystemCoreClock CMSIS variable.

Note

Variable can be calculated also through SystemCoreClockUpdate function.

Parameters

CPU_Frequency

Core frequency in Hz

Note

CPU_Frequency can be calculated thanks to RCC helper macro or function LL_RCC_GetSystemClocksFreq

Return values

None