STM32CubeF4

/**
  @page TIM_OCToggle TIM_OCToggle example
  
  @verbatim
  ******************** (C) COPYRIGHT 2017 STMicroelectronics *******************
  * @file    TIM/TIM_OCToggle/readme.txt 
  * @author  MCD Application Team
  * @brief   This example shows how to configure the Timer to generate four different 
  *          signals with four different frequencies.
  ******************************************************************************
  *
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  * are permitted provided that the following conditions are met:
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  *      this list of conditions and the following disclaimer.
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  *      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 its contributors
  *      may be used to endorse or promote products derived from this software
  *      without specific prior written permission.
  *
  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
  * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
  * DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE
  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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  * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  *
  ******************************************************************************
  @endverbatim

@par Example Description 

  This example shows how to configure the TIM peripheral to generate four different 
  signals with four different frequencies.

  The TIM4 frequency is set to SystemCoreClock, and the objective is
  to get TIM4 counter clock at 12.5 MHz so the Prescaler is computed as following:
     - Prescaler = (TIM4CLK /TIM4 counter clock) - 1
   
  SystemCoreClock is set to 100 MHz for STM32F4xx Devices.

  The TIM4 CCR1 register value is equal to 32051:
  CC1 update rate = TIM4 counter clock / CCR1_Val = 390 Hz,
  so the TIM4 Channel 1 generates a periodic signal with a frequency equal to 195 Hz.

  The TIM4 CCR2 register value is equal to 16025:
  CC2 update rate = TIM4 counter clock / CCR2_Val = 780 Hz,
  so the TIM4 channel 2 generates a periodic signal with a frequency equal to 390 Hz.

  The TIM4 CCR3 register value is equal to 8012:
  CC3 update rate = TIM4 counter clock / CCR3_Val = 1560 Hz,
  so the TIM4 channel 3 generates a periodic signal with a frequency equal to 780 Hz.

  The TIM4 CCR4 register value is equal to 4006:
  CC4 update rate = TIM4 counter clock / CCR4_Val =  3120 Hz,
  so the TIM4 channel 4 generates a periodic signal with a frequency equal to 1560 Hz.

@note PWM signal frequency values mentioned above are theoretical (obtained when the system clock frequency
      is exactly 100 MHz). Since the generated system clock frequency may vary from one board to another observed
      PWM signal frequency might be slightly different.
	  
@note Care must be taken when using HAL_Delay(), this function provides accurate delay (in milliseconds)
      based on variable incremented in SysTick ISR. This implies that if HAL_Delay() is called from
      a peripheral ISR process, then the SysTick interrupt must have higher priority (numerically lower)
      than the peripheral interrupt. Otherwise the caller ISR process will be blocked.
      To change the SysTick interrupt priority you have to use HAL_NVIC_SetPriority() function.
      
@note The application need to ensure that the SysTick time base is always set to 1 millisecond
      to have correct HAL operation.

@par Keywords

Timers, Output, signals, Outpur compare toggle, PWM, Oscilloscope

@par Directory contents 

  - TIM/TIM_OCToggle/Inc/stm32f4xx_hal_conf.h    HAL configuration file
  - TIM/TIM_OCToggle/Inc/stm32f4xx_it.h          Interrupt handlers header file
  - TIM/TIM_OCToggle/Inc/main.h                  Header for main.c module  
  - TIM/TIM_OCToggle/Src/stm32f4xx_it.c          Interrupt handlers
  - TIM/TIM_OCToggle/Src/main.c                  Main program
  - TIM/TIM_OCToggle/Src/stm32f4xx_hal_msp.c     HAL MSP file
  - TIM/TIM_OCToggle/Src/system_stm32f4xx.c      STM32F4xx system source file


@par Hardware and Software environment

  - This example runs on STM32F412xG devices.
    
  - This example has been tested with STMicroelectronics STM32412G-DISCOVERY 
    board and can be easily tailored to any other supported device 
    and development board.      

  - STM32412G-DISCOVERY Set-up
   Connect the following pins to an oscilloscope to monitor the different waveforms:
      - PB.06: (TIM4_CH1) (connected to PB.06 (pin 23 in P2 connector))
      - PB.07: (TIM4_CH2) (connected to PB.07 (pin 24 in P2 connector))
      - PB.08: (TIM4_CH3) (connected to PB.08 (pin 19 in P2 connector))
      - PB.09: (TIM4_CH4) (connected to PB.09 (pin 20 in P2 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>&copy; COPYRIGHT STMicroelectronics</center></h3>
 */