Hal_Rcc_Disablecss; Hal_Rcc_Getsysclockfreq; Hal_Rcc_Gethclkfreq - ST STM32F2 User Manual

UM1940

HAL_RCC_DisableCSS

Function name
Function description
Return values

HAL_RCC_GetSysClockFreq

Function name
Function description
Return values
Notes

HAL_RCC_GetHCLKFreq

Function name
Function description
Return values
Notes
void HAL_RCC_DisableCSS (void )
Disables the Clock Security System.
None:
uint32_t HAL_RCC_GetSysClockFreq (void )
Returns the SYSCLK frequency.
SYSCLK: frequency
The system frequency computed by this function is not the
real frequency in the chip. It is calculated based on the
predefined constant and the selected clock source:
If SYSCLK source is HSI, function returns values based on
HSI_VALUE(*)
If SYSCLK source is HSE, function returns values based on
HSE_VALUE(**)
If SYSCLK source is PLL, function returns values based on
HSE_VALUE(**) or HSI_VALUE(*) multiplied/divided by the
PLL factors.
(*) HSI_VALUE is a constant defined in stm32f2xx_hal_conf.h
file (default value 16 MHz) but the real value may vary
depending on the variations in voltage and temperature.
(**) HSE_VALUE is a constant defined in
stm32f2xx_hal_conf.h file (default value 25 MHz), user has to
ensure that HSE_VALUE is same as the real frequency of the
crystal used. Otherwise, this function may have wrong result.
The result of this function could be not correct when using
fractional value for HSE crystal.
This function can be used by the user application to compute
the baudrate for the communication peripherals or configure
other parameters.
Each time SYSCLK changes, this function must be called to
update the right SYSCLK value. Otherwise, any configuration
based on this function will be incorrect.
uint32_t HAL_RCC_GetHCLKFreq (void )
Returns the HCLK frequency.
HCLK: frequency
Each time HCLK changes, this function must be called to
update the right HCLK value. Otherwise, any configuration
based on this function will be incorrect.
The SystemCoreClock CMSIS variable is used to store
System Clock Frequency and updated within this function
DocID028236 Rev 2
HAL RCC Generic Driver
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