/**
  @page FatFs_USBDisk   FatFs with USB disk drive example
 
  @verbatim
  ******************** (C) COPYRIGHT 2014 STMicroelectronics *******************
  * @file    readme.txt 
  * @author  MCD Application Team
  * @version V1.0.1
  * @date    26-February-2014
  * @brief   Description of the FatFs with USB disk drive example
  ******************************************************************************
  *
  * Licensed under MCD-ST Liberty SW License Agreement V2, (the "License");
  * You may not use this file except in compliance with the License.
  * You may obtain a copy of the License at:
  *
  *        http://www.st.com/software_license_agreement_liberty_v2
  *
  * Unless required by applicable law or agreed to in writing, software 
  * distributed under the License is distributed on an "AS IS" BASIS, 
  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  * See the License for the specific language governing permissions and
  * limitations under the License.
  *
  ******************************************************************************
    @endverbatim

@par Example Description

This example provides a description on how to use STM32Cube firmware with FatFs 
middleware component as a generic FAT file system module and STM32 USB On-The-Go
(OTG) host library, in both Full Speed (FS) and High Speed (HS) modes,
in order to develop an application exploiting FatFs offred features with USB 
disk drive configuration.

At the beginning of the main program the HAL_Init() function is called to reset 
all the peripherals, initialize the Flash interface and the systick.
Then the SystemClock_Config() function is used to configure the system clock
(SYSCLK) to run at 168 MHz.
           
The application is based on writing  a text file to a drive, and it's performed 
using FatFs APIs to access the FAT volume as described in the following steps: 

 - Link the USB Host disk I/O driver;
 - Register the file system object (mount) to the FatFs module for the USB drive;
 - Create and Open new text file object with write access;
 - Write data to the text file;
 - Close the open text file;
 - Open text file object with read access;
 - Read back data from the text file;
 - Close the open text file;
 - Check on read data from text file;
 - Unlink the USB Host disk I/O driver.

It is worth noting that the application manages any error occurred during the 
access to FAT volume, when using FatFs APIs. Otherwise, user can check if the
written text file is available on the USB disk. 

It is possible to fine tune needed FatFs features by modifying defines values 
in FatFs configuration file ffconf.h available under the project includes 
directory, in a way to fit the application requirements. 

STM32 Eval board's LEDs can be used to monitor the example status:
  - LED1 is ON when the example runs successfully.
  - LED3 is ON when any error occurs.


@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 Directory contents
 
  - FatFs/FatFs_USBDisk_RTOS/Inc/stm32f4xx_hal_conf.h    HAL configuration file
  - FatFs/FatFs_USBDisk_RTOS/Inc/stm32f4xx_it.h          Interrupt handlers header file
  - FatFs/FatFs_USBDisk_RTOS/Inc/main.h                  Header for main.c module
  - FatFs/FatFs_USBDisk_RTOS/Inc/ffconf.h                FAT file system module configuration file   
  - FatFs/FatFs_USBDisk_RTOS/Src/stm32f4xx_it.c          Interrupt handlers
  - FatFs/FatFs_USBDisk_RTOS/Src/main.c                  Main program
  - FatFs/FatFs_USBDisk_RTOS/Src/system_stm32f4xx.c      STM32F4xx system source file


@par Hardware and Software environment

  - This example runs on STM32F407xx/417xx devices.
    
  - This example has been tested with STMicroelectronics STM324xG-EVAL RevC 
    evaluation boards and can be easily tailored to any other supported device 
    and development board. 

  - STM324xG-EVAL Set-up
    - Plug the USB key into the STM324xG-EVAL board through 'USB micro A-Male 
      to A-Female' cable to the connector:
      - CN9 : to use USB High Speed (HS) with embedded PHY(U7)
      - CN14: to use USB Full Speed (FS)


@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
  - In the workspace toolbar select the project configuration:
   - STM324xG-EVAL_USBH-HS: to configure the project for STM32F4xx devices using USB OTG HS peripheral
   - STM324xG-EVAL_USBH-FS: to configure the project for STM32F4xx devices using USB OTG FS peripheral
 - Run the example

 * <h3><center>&copy; COPYRIGHT STMicroelectronics</center></h3>
 */
 