83 lines
3.3 KiB
Plaintext
83 lines
3.3 KiB
Plaintext
/**
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@page RCC_HWAutoMSICalibration RCC example
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@verbatim
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******************************************************************************
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* @file Examples_LL/RCC/RCC_HWAutoMSICalibration/readme.txt
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* @author MCD Application Team
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* @brief Description of the RCC example.
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******************************************************************************
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*
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* Copyright (c) 2020 STMicroelectronics. All rights reserved.
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*
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* This software component is licensed by ST under BSD 3-Clause license,
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* the "License"; You may not use this file except in compliance with the
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* License. You may obtain a copy of the License at:
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* opensource.org/licenses/BSD-3-Clause
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*
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******************************************************************************
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@endverbatim
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@par Example Description
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Use of the MSI clock source hardware autocalibration and LSE clock (PLL mode) to obtain a precise MSI clock.
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In the associated software, after start-up, SYSCLK is configured to the max
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frequency using the PLL with MSI as clock source.
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When a 32.768 kHz external oscillator is present in the application,it is possible to configure
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the MSI in a PLL-mode by setting the MSIPLLEN bit.
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When configured in PLL-mode, the MSI automatically calibrates itself thanks to the LSE.
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This mode is available for all MSI frequency ranges. At 48 MHz, the MSI in PLL-mode can
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be used for the USB OTG FS device, saving the need of an external high-speed crystal.
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The program waits until User push-button (B1) is pressed to begin the auto calibration
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procedure (fast blink of the LED2):
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- Enable and wait for LSE is ready.
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- Enable PLL-Mode feature
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- LED2 is turn on to indicate end of the HW calibration procedure.
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@note User can connect on oscilloscope to MCO pin (PA.08) to check MSI frequency before and after
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calibration procedure.
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@note User can enable USE_TIMEOUT switch to detect a problem with LSE activation (LED2 is blinking
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every 1 sec in case of issue)
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@par Keywords
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RCC, System, MSI clock , PLL-mode, LSE clock, PLL
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@par Directory contents
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- RCC/RCC_HWAutoMSICalibration/Inc/stm32wlxx_it.h Interrupt handlers header file
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- RCC/RCC_HWAutoMSICalibration/Inc/main.h Header for main.c module
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- RCC/RCC_HWAutoMSICalibration/Inc/stm32_assert.h Template file to include assert_failed function
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- RCC/RCC_HWAutoMSICalibration/Src/stm32wlxx_it.c Interrupt handlers
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- RCC/RCC_HWAutoMSICalibration/Src/main.c Main program
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- RCC/RCC_HWAutoMSICalibration/Src/system_stm32wlxx.c STM32WLxx system source file
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@par Hardware and Software environment
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- This example runs on STM32WL55JCIx devices.
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- This example has been tested with NUCLEO-WL55JC RevC board and can be
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easily tailored to any other supported device and development board.
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- NUCLEO-WL55JC RevC Set-up
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- External LSE Oscillator is mandatory to be able to run this example.
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- Connect the MCO pin to an oscilloscope to monitor the different waveforms:
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- PA.08: connector CN10 pin 16
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@par How to use it ?
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In order to make the program work, you must do the following :
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- Open your preferred toolchain
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- Rebuild all files and load your image into target memory
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- Run the example
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* <h3><center>© COPYRIGHT STMicroelectronics</center></h3>
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*/
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