mirror of
https://github.com/STMicroelectronics/STM32CubeF0.git
synced 2025-05-08 19:29:49 +08:00
79 lines
3.4 KiB
Plaintext
79 lines
3.4 KiB
Plaintext
/**
|
|
@page CRS_Synchronization_Polling CRS example
|
|
|
|
@verbatim
|
|
******************** (C) COPYRIGHT 2016 STMicroelectronics *******************
|
|
* @file Examples_LL/CRS/CRS_Synchronization_Polling/readme.txt
|
|
* @author MCD Application Team
|
|
* @brief Description of the CRS_Synchronization_Polling example.
|
|
******************************************************************************
|
|
* @attention
|
|
*
|
|
* <h2><center>© Copyright (c) 2016 STMicroelectronics.
|
|
* All rights reserved.</center></h2>
|
|
*
|
|
* This software component is licensed by ST under BSD 3-Clause license,
|
|
* the "License"; You may not use this file except in compliance with the
|
|
* License. You may obtain a copy of the License at:
|
|
* opensource.org/licenses/BSD-3-Clause
|
|
*
|
|
******************************************************************************
|
|
@endverbatim
|
|
|
|
@par Example Description
|
|
|
|
How to configure the clock recovery service in polling mode through the
|
|
STM32F0xx CRS LL API. The peripheral initialization uses LL unitary
|
|
service functions for optimization purposes (performance and size).
|
|
|
|
At the beginning of the main program the SystemClock_Config() function is used to
|
|
configure the system clock (SYSCLK) to run at 48 MHz.
|
|
|
|
Then, HSI48 and LSE oscillators are enabled. In this example CRS will use LSE
|
|
oscillator to calibrate HSI48 frequency.
|
|
When HSI48 and LSE are started, automatic calibration starts and program call the
|
|
polling function to wait for synchronization status.
|
|
|
|
In this test, there are results which could occur:
|
|
- Wait for User push-button press to start the test (Fast toggle LED2)
|
|
- few loops occurs up to SYNC OK event (if SYNC WARN, HSI48 trimming value will be
|
|
automatically modified)
|
|
- in case of SYNC MISS or SYNC ERROR, there is an issue with synchronization input
|
|
parameters. In this case, user need to apply new parameters after checking synchronization
|
|
information and restart the synchronization.
|
|
- LED2 is slowly blinking (1 sec. period) in case of timeout during polling
|
|
procedure. It may due to an issue with LSE synchronization frequency.
|
|
- LED2 will finally power on if SYNC OK is returned by CRS.
|
|
|
|
@par Directory contents
|
|
|
|
- CRS/CRS_Synchronization_Polling/Inc/stm32f0xx_it.h Interrupt handlers header file
|
|
- CRS/CRS_Synchronization_Polling/Inc/main.h Header for main.c module
|
|
- CRS/CRS_Synchronization_Polling/Inc/stm32_assert.h Template file to include assert_failed function
|
|
- CRS/CRS_Synchronization_Polling/Src/stm32f0xx_it.c Interrupt handlers
|
|
- CRS/CRS_Synchronization_Polling/Src/main.c Main program
|
|
- CRS/CRS_Synchronization_Polling/Src/system_stm32f0xx.c STM32F0xx system source file
|
|
|
|
|
|
@par Hardware and Software environment
|
|
|
|
- This example runs on STM32F072xB devices.
|
|
|
|
- This example has been tested with STM32F072RB-Nucleo RevC board and can be
|
|
easily tailored to any other supported device and development board.
|
|
|
|
- STM32F072RB-Nucleo RevC Set-up
|
|
- Connect the MCO pin to an oscilloscope to monitor HSI48 frequency:
|
|
- PA.08: connected to pin 23 of CN10 connector
|
|
|
|
|
|
@par How to use it ?
|
|
|
|
In order to make the program work, you must do the following :
|
|
- Open your preferred toolchain
|
|
- Rebuild all files and load your image into target memory
|
|
- Run the example
|
|
|
|
* <h3><center>© COPYRIGHT STMicroelectronics</center></h3>
|
|
*/
|