/**
  @page TIM_Encoder Encoder example

  @verbatim
  ******************** (C) COPYRIGHT 2017 STMicroelectronics *******************
  * @file    TIM/TIM_Encoder/Readme.txt 
  * @author  MCD Application Team
  * @brief   This example shows how to configure the Timer in Encoder interface 
  *          to determinate the rotation direction. 
  ******************************************************************************
  *
  * 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
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  * 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 

This example shows how to configure the TIM1 peripheral in encoder mode to
determinate the rotation direction.
                                     
     -------------                               -------------
    |             |CH1:PC6              CH1:PA8 |             |
    |             |---------------------------->|             |
    |    TIM3     |                             |    TIM1     |
    |             |CH1:PC7             CH1:PE11 |             |
    | Quadrature  |---------------------------->| Quadrature  |
    | encoder     |                             | encoder     |
    | emulator    |                             | interface   |
    |             |                             |             |
    |             |                             |             |
    |             |                             |-------------|     -----------
    |             |                             |  Direction  |--> |uwDirection|     
     -------------                               -------------      -----------
               Encoder interface example description
               
               

  To emulate a quadrature encoder, TIM3 is configured in toggle mode to generate
2 quadrature signals on (PC6 and PC7) at 10KHz. Each 1s, signals change phase
(+90°/-90°) to emulate a Forward/Backward rotation.  

  TIM1 is configured in encoder mode interface, counting on TI1 and TI2.
  The counting direction corresponds to the rotation direction of the connected 
sensor (emulated by TIM3 signals).
Rotation direction can be monitored by putting "uwDirection" variable in the 
Live Watch window.
  When uwDirection = 0, and according to the "Counting direction versus encoder
signals" table, rotation direction is Forward.
  When uwDirection = 1, and according to the "Counting direction versus encoder
signals" table, rotation direction is Backward.

@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 needs to ensure that the SysTick time base is always set to 1 millisecond
      to have correct HAL operation.

@note LED4 is turned ON, because it's sharing the same GPIO pin with the TIM3 channel 2.

@par Directory contents 

  - TIM/TIM_Encoder/Inc/stm32f2xx_conf.h     Library Configuration file
  - TIM/TIM_Encoder/Inc/stm32f2xx_it.h       Interrupt handlers header file
  - TIM/TIM_Encoder/Inc/main.h               Main program header file  
  - TIM/TIM_Encoder/Src/stm32f2xx_it.c       Interrupt handlers
  - TIM/TIM_Encoder/Src/main.c               Main program
  - TIM/TIM_Encoder/Src/stm32f2xx_hal_msp.c  HAL MSP file
  - TIM/TIM_Encoder/Src/system_stm32f2xx.c   STM32F2xx system clock configuration file

    
@par Hardware and Software environment 

  - This example runs on STM32F207xx/217xx device.
    
  - This example has been tested with STMicroelectronics STM322xG-EVAL  
    evaluation boards and can be easily tailored to any other supported device and development board

  - STM322xG-EVAL Set-up 
    - Connect PC6(Pin21 in CN3) (TIM3_Channel 1) to PA8(Pin16 in CN3) (TIM1_Channel 1).
    - Connect PC7(Pin20 in CN3) (TIM3_Channel 2) to PE11(Pin26 in CN2) (TIM1_Channel 2).
    - Put uwDirection in the debugger live watch to detect the rotation direction
      change.
    
@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>
 */
