/**
  @page SPI_OneBoard_HalfDuplex_DMA_Init SPI example
  
  @verbatim
  ******************** (C) COPYRIGHT 2016 STMicroelectronics *******************
  * @file    Examples_LL/SPI/SPI_OneBoard_HalfDuplex_DMA_Init/readme.txt 
  * @author  MCD Application Team
  * @brief   Description of the SPI_OneBoard_HalfDuplex_DMA_Init example.
  ******************************************************************************
  * @attention
  *
  * <h2><center>&copy; Copyright (c) 2016 STMicroelectronics.
  * All rights reserved.</center></h2>
  *
  * This software component is licensed by ST under BSD 3-Clause license,
  * the "License"; You may not use this file except in compliance with the
  * License. You may obtain a copy of the License at:
  *                        opensource.org/licenses/BSD-3-Clause
  *
  ******************************************************************************
  @endverbatim

@par Example Description

Configuration of GPIO and SPI peripherals to transmit 
bytes from an SPI Master device to an SPI Slave device in DMA mode. This example
is based on the STM32F1xx SPI LL API. The peripheral initialization uses the 
LL initialization function to demonstrate LL init usage.

This example works with only one STM32F103RB-Nucleo.

SPI1 Peripheral is configured in Master mode Half-Duplex Tx.
SPI2 Peripheral is configured in Slave mode Half-Duplex Rx.
GPIO associated to User push-button is linked with EXTI. 

Example execution:

LED2 is blinking Fast (200ms) and wait User push-button action.
Press User push-button on BOARD start a Half-Duplex communication through DMA.
On MASTER side (SPI1), Clock will be generated on SCK line, Transmission done on MOSI Line.
On SLAVE side (SPI2) reception is done through the MISO Line.

LED2 is On if data is well received.

In case of errors, LED2 is blinking Slowly (1s).
@note You need to perform a reset on the board,then press the User button on 
       board to have the correct behaviour of this example.

@note Since some SPI1 pins (PB3/PB4) are mapped onto some pins used by the JTAG,
      a remap of SPI1 pins and disable of the JTAG are performed.

@par Directory contents 

  - SPI/SPI_OneBoard_HalfDuplex_DMA_Init/Inc/stm32f1xx_it.h          Interrupt handlers header file
  - SPI/SPI_OneBoard_HalfDuplex_DMA_Init/Inc/main.h                  Header for main.c module
  - SPI/SPI_OneBoard_HalfDuplex_DMA_Init/Inc/stm32_assert.h          Template file to include assert_failed function
  - SPI/SPI_OneBoard_HalfDuplex_DMA_Init/Src/stm32f1xx_it.c          Interrupt handlers
  - SPI/SPI_OneBoard_HalfDuplex_DMA_Init/Src/main.c                  Main program
  - SPI/SPI_OneBoard_HalfDuplex_DMA_Init/Src/system_stm32f1xx.c      STM32F1xx system source file

@par Hardware and Software environment

  - This example runs on STM32F103xB devices.

  - This example has been tested with STM32F103RB-Nucleo board and can be
    easily tailored to any other supported device and development board.

  - STM32F103RB-Nucleo Set-up
    - Connect Master SCK  PB3 to Slave SCK  PB13
    - Connect Master MOSI PB5 to Slave MISO PB14

Relation with Board connector:
  PB3 is connected to pin 31 of CN10 connector
  PB5 is connected to pin 29 of CN10 connector
  PB13 is connected to pin 30 of CN10 connector
  PB14 is connected to pin 28 of CN10 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>
 */
