STM32CubeF0

/**
  @page TIM_TimeBase Timebase example
  
  @verbatim
  ******************** (C) COPYRIGHT 2016 STMicroelectronics *******************
  * @file    TIM/TIM_TimeBase/readme.txt 
  * @author  MCD Application Team
  * @brief   Description of the TIM Timebase example
  ******************************************************************************
  *
  * Redistribution and use in source and binary forms, with or without modification,
  * are permitted provided that the following conditions are met:
  *   1. Redistributions of source code must retain the above copyright notice,
  *      this list of conditions and the following disclaimer.
  *   2. Redistributions in binary form must reproduce the above copyright notice,
  *      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
  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
  * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
  * CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
  * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
  * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  *
  ******************************************************************************
  @endverbatim

@par Example Description 

Configuration of the TIM peripheral to generate a timebase of 
one second with the corresponding interrupt request.

    In this example TIM2 input clock (TIM2CLK)  is set to APB1 clock (PCLK1),
    since APB1 prescaler is equal to 1.
      TIM2CLK = PCLK1
      PCLK1 = HCLK
      => TIM2CLK = HCLK = SystemCoreClock
    To get TIM2 counter clock at 10 KHz, the Prescaler is computed as following:
    Prescaler = (TIM2CLK / TIM2 counter clock) - 1
    Prescaler = (SystemCoreClock /10 KHz) - 1

SystemCoreClock is set to 48 MHz for STM32F0xx Devices.

The TIM2 ARR register value is equal to 10000 - 1, 
Update rate = TIM2 counter clock / (Period + 1) = 1 Hz,
So the TIM2 generates an interrupt each 1 s

When the counter value reaches the auto-reload register value, the TIM upadate 
interrupt is generated and, in the handler routine, PA.05 is toggled with the 
following frequency: 

- PA.05 : 0.5Hz

In case of error, LED2 is turned ON.

@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 Timebase is always set to 1 millisecond
      to have correct HAL operation.

@par Directory contents 

  - TIM/TIM_TimeBase/Inc/stm32f0xx_hal_conf.h    HAL configuration file
  - TIM/TIM_TimeBase/Inc/stm32f0xx_it.h          Interrupt handlers header file
  - TIM/TIM_TimeBase/Inc/main.h                  Header for main.c module  
  - TIM/TIM_TimeBase/Src/stm32f0xx_it.c          Interrupt handlers
  - TIM/TIM_TimeBase/Src/main.c                  Main program
  - TIM/TIM_TimeBase/Src/stm32f0xx_hal_msp.c     HAL MSP file
  - TIM/TIM_TimeBase/Src/system_stm32f0xx.c      STM32F0xx system source file


@par Hardware and Software environment

  - This example runs on STM32F072RB devices.
    
  - This example has been tested with STMicroelectronics STM32F072RB-Nucleo RevC
    board and can be easily tailored to any other supported device
    and development board.      

  - STM32F072RB-Nucleo RevC Set-up
    - Use LED2 connected to PA.05 pin and connect them on an oscilloscope 
      to show the Timebase signal.  


@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>
 */