STM32CubeF4

@verbatim
******************** (C) COPYRIGHT 2017 STMicroelectronics *******************
* @file Examples_LL/RCC/RCC_OutputSystemClockOnMCO/readme.txt
* @author MCD Application Team
* @brief Description of the RCC example.
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@endverbatim

@par Example Description

This example describes how to configure MCO pins (PA8 and PC9) to output the system clock.

At start-up, USER button and MCO pin are configured. The program configures SYSCLK
to the max frequency using the PLL with HSE as clock source.

The signal on PA8 and PC9 can be monitored with an oscilloscope
to check the different MCO configuration set at each button press.
Different configuration will be observed
- HSI frequency with frequency value around @16MHz.
- PLLCLK frequency value divided by 4, hence around @25MHz.
- SYSCLK frequency value divided by 2, hence around @50MHz.
- HSE frequency value divided by 2, hence around @4MHz.

When user press User push-button, a LED2 toggle is done to indicate a change in MCO config.

@par Directory contents

- RCC/RCC_OutputSystemClockOnMCO/Inc/stm32f4xx_it.h Interrupt handlers header file
- RCC/RCC_OutputSystemClockOnMCO/Inc/main.h Header for main.c module
- RCC/RCC_OutputSystemClockOnMCO/Inc/stm32_assert.h Template file to include assert_failed function
- RCC/RCC_OutputSystemClockOnMCO/Src/stm32f4xx_it.c Interrupt handlers
- RCC/RCC_OutputSystemClockOnMCO/Src/main.c Main program
- RCC/RCC_OutputSystemClockOnMCO/Src/system_stm32f4xx.c STM32F4xx system source file

@par Hardware and Software environment

- This example runs on STM32F411xE devices.

- This example has been tested with NUCLEO-F411RE board and can be
easily tailored to any other supported device and development board.

- NUCLEO-F411RE Set-up
- Connect the MCO pin to an oscilloscope to monitor the different waveforms:
- PA.08: connected to pin 23 of CN10 connector for Nucleo-64 (MB1136)
- PC.09: connected to pin 1 of CN10 connector for Nucleo-64 (MB1136)

@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