/**
  @page UART_Printf UART Printf example
  
  @verbatim
  ******************** (C) COPYRIGHT 2017 STMicroelectronics *******************
  * @file    UART/UART_Printf/readme.txt 
  * @author  MCD Application Team
  * @brief   Description of the UART Printf 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 

This example shows how to reroute the C library printf function to the UART. It 
outputs a message sent by the UART on the HyperTerminal.

   _________________________ 
  |           ______________|                       _______________
  |          |USART1        |                      | Hyperterminal |
  |          |              |                      |               |
  |          |       TX(PA9)|______________________|RX             |
  |          |              |                      |               |
  |          |              |     RS232 Cable      |               |             
  |          |              |                      |               |
  |          |      RX(PA10)|______________________|TX             |          
  |          |              |                      |               |           
  |          |______________|                      |_______________|          
  |                         |                       
  |                         |                    
  |                         |                      
  |                         |                      
  |_STM324x9I_______________|                

This implementation output the printf message on the Hyperterminal using USART1.

The USART1 is configured as follows:
    - BaudRate = 9600 baud  
    - Word Length = 8 Bits
    - One Stop Bit
    - ODD parity
    - Hardware flow control disabled (RTS and CTS signals)
    - Receive and transmit enabled


@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.

@par Keywords

Connectivity, UART, Printf, Baud rate, RS-232, HyperTerminal, full-duplex

@par Directory contents 

  - UART/UART_Printf/Inc/stm32f4xx_hal_conf.h    HAL configuration file
  - UART/UART_Printf/Inc/stm32f4xx_it.h          Interrupt handlers header file
  - UART/UART_Printf/Inc/main.h                  Main program header file  
  - UART/UART_Printf/Src/stm32f4xx_it.c          Interrupt handlers
  - UART/UART_Printf/Src/main.c                  Main program
  - UART/UART_Printf/Src/stm32f4xx_hal_msp.c     HAL MSP module
  - UART/UART_Printf/Src/system_stm32f4xx.c      STM32F4xx system clock configuration file


@par Hardware and Software environment

  - This example runs on STM32F42xxx/STM32F43xxx devices
    
  - This example has been tested with STM324x9I-EVAL RevB evaluation board and can be
    easily tailored to any other supported device and development board.    

  - STM324x9I-EVAL RevB Set-up
    - Connect a null-modem female/female RS232 cable between the DB9 connector 
      CN8 (USART1) and PC serial port if you want to display data on the Hyperterminal.
    - Please ensure that jumper JP7 is in position RS232_RX
     
  - Hyperterminal configuration:
    - Word Length = 7 Bits
    - One Stop Bit
    - Odd parity
    - BaudRate = 9600 baud
    - flow control: None 
    
    
@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>
 */