/**
@page RCC_HWAutoMSICalibration RCC example
@verbatim
******************************************************************************
* @file Examples_LL/RCC/RCC_HWAutoMSICalibration/readme.txt
* @author MCD Application Team
* @brief Description of the RCC example.
******************************************************************************
*
* Copyright (c) 2020 STMicroelectronics. All rights reserved.
*
* 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
Use of the MSI clock source hardware autocalibration and LSE clock (PLL mode) to obtain a precise MSI clock.
In the associated software, after start-up, SYSCLK is configured to the max
frequency using the PLL with MSI as clock source.
When a 32.768 kHz external oscillator is present in the application,it is possible to configure
the MSI in a PLL-mode by setting the MSIPLLEN bit.
When configured in PLL-mode, the MSI automatically calibrates itself thanks to the LSE.
This mode is available for all MSI frequency ranges. At 48 MHz, the MSI in PLL-mode can
be used for the USB OTG FS device, saving the need of an external high-speed crystal.
The program waits until User push-button (B1) is pressed to begin the auto calibration
procedure (fast blink of the LED2):
- Enable and wait for LSE is ready.
- Enable PLL-Mode feature
- LED2 is turn on to indicate end of the HW calibration procedure.
@note User can connect on oscilloscope to MCO pin (PA.08) to check MSI frequency before and after
calibration procedure.
@note User can enable USE_TIMEOUT switch to detect a problem with LSE activation (LED2 is blinking
every 1 sec in case of issue)
@par Keywords
RCC, System, MSI clock , PLL-mode, LSE clock, PLL
@par Directory contents
- RCC/RCC_HWAutoMSICalibration/Inc/stm32wlxx_it.h Interrupt handlers header file
- RCC/RCC_HWAutoMSICalibration/Inc/main.h Header for main.c module
- RCC/RCC_HWAutoMSICalibration/Inc/stm32_assert.h Template file to include assert_failed function
- RCC/RCC_HWAutoMSICalibration/Src/stm32wlxx_it.c Interrupt handlers
- RCC/RCC_HWAutoMSICalibration/Src/main.c Main program
- RCC/RCC_HWAutoMSICalibration/Src/system_stm32wlxx.c STM32WLxx system source file
@par Hardware and Software environment
- This example runs on STM32WL55JCIx devices.
- This example has been tested with NUCLEO-WL55JC RevC board and can be
easily tailored to any other supported device and development board.
- NUCLEO-WL55JC RevC Set-up
- External LSE Oscillator is mandatory to be able to run this example.
- Connect the MCO pin to an oscilloscope to monitor the different waveforms:
- PA.08: connector CN10 pin 16
@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>
*/
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