ST STM32F31xx User Manual

UM1581
Reset and clock control (RCC)
DocID023800 Rev 1
325/584
18.2.7.6 RCC_GetClocksFreq
Function Name
void RCC_GetClocksFreq ( RCC_ClocksTypeDef *
RCC_Clocks)
Function Description
Returns the frequencies of the System, AHB, APB2 and APB1
busses clocks.
Parameters
 RCC_Clocks : pointer to a RCC_ClocksTypeDef structure
which will hold the clocks frequencies.
Return values
 None.
Notes
 This function returns the frequencies of : System, AHB, APB2
and APB1 busses clocks, ADC1/2/3/4 clocks,
USART1/2/3/4/5 clocks, I2C1/2 clocks and TIM1/8 Clocks.
 The frequency returned by this function is not the real
frequency in the chip. It is calculated based on the predefined
constant and the source selected by RCC_SYSCLKConfig().
 If SYSCLK source is HSI, function returns constant
HSI_VALUE(*)
 If SYSCLK source is HSE, function returns constant
HSE_VALUE(**)
 If SYSCLK source is PLL, function returns constant
HSE_VALUE(**) or HSI_VALUE(*) multiplied by the PLL
factors.
 (*) HSI_VALUE is a constant defined in stm32f30x.h file
(default value 8 MHz) but the real value may vary depending
on the variations in voltage and temperature, refer to
RCC_AdjustHSICalibrationValue().
 (**) HSE_VALUE is a constant defined in stm32f30x.h file
(default value 8 MHz), user has to ensure that HSE_VALUE is
same as the real frequency of the crystal used. Otherwise,
this function may return 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, HCLK, PCLK1 and/or PCLK2 clock
changes, this function must be called to update the structure's
field. Otherwise, any configuration based on this function will
be incorrect.
18.2.8 Peripheral clocks configuration functions
18.2.8.1 RCC_ADCCLKConfig

ST STM32F31xx Specifications

General

Brand	ST
Model	STM32F31xx
Category	Microcontrollers
Language	English