clocks.h File Reference

Clocks driver Based on stm32l1xx_rcc.c from ST Library. More...

#include <os.h>

Go to the source code of this file.

Data Structures
struct	clocks_t

Functions
void	clocks_get_freq (clocks_t *clocks)
	Gets the frequencies of various system clocks. More...

Detailed Description

Clocks driver Based on stm32l1xx_rcc.c from ST Library.

Copyright (c) 2015 STMicroelectronics International N.V.. All rights reserved. Copyright (c) 2018, Archos S.A.

Redistribution and use in source and binary forms, with or without modification, are permitted, provided that the following conditions are met:

1. Redistribution of source code must retain the above copyright notice, this list of conditions and the following disclaimer.
2. Redistributions in binary form must reproduce the above copyright notice, this list of conditions and the following disclaimer in the documentation and/or other materials provided with the distribution.
3. Neither the name of STMicroelectronics nor the names of other contributors to this software may be used to endorse or promote products derived from this software without specific written permission.
4. This software, including modifications and/or derivative works of this software, must execute solely and exclusively on microcontroller or microprocessor devices manufactured by or for STMicroelectronics.
5. Redistribution and use of this software other than as permitted under this license is void and will automatically terminate your rights under this license.

THIS SOFTWARE IS PROVIDED BY STMICROELECTRONICS AND CONTRIBUTORS "AS IS" AND EXPRESS, IMPLIED OR STATUTORY WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NON-INFRINGEMENT OF THIRD PARTY INTELLECTUAL PROPERTY RIGHTS ARE DISCLAIMED TO THE FULLEST EXTENT PERMITTED BY LAW. IN NO EVENT SHALL STMICROELECTRONICS OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

Function Documentation

void clocks_get_freq

(

clocks_t *

clocks

)

Gets the frequencies of various system clocks.

Parameters

clocks

The structure that will hold the frequencies of the clocks.

Gets the frequencies of various system clocks.

Note

The frequency returned by this function is not the real frequency in the chip. It is calculated based on the predefined constant and the SYSCLK source:

If SYSCLK source is MSI, function returns values based on MSI value as defined by the MSI range

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 stm32l1xx.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 stm32l1xx.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.

Parameters

clocks

pointer to a clocks_t structure which will hold the clocks frequencies.

Note

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.

Return values

None