/**
  @page MSC_RTOS USB Host Mass Storage (MSC) RTOS example
  
  @verbatim
  ******************** (C) COPYRIGHT 2014 STMicroelectronics *******************
  * @file    USB_Host/MSC_RTOS/readme.txt 
  * @author  MCD Application Team
  * @version V1.0.1
  * @date    26-February-2014
  * @brief   Description of the USB Host MSC RTOS 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 is a part of the USB Host Library package using STM32Cube firmware. It describes how to use
USB host application based on the Mass Storage Class (MSC) on the STM32F4xx devices in RTOS mode
configuration.

This is a typical example on how to use the STM32F4xx USB OTG Host peripheral to operate with an USB 
flash disk using the Bulk Only Transfer (BOT) and Small Computer System Interface (SCSI) transparent
commands combined with a file system FatFs (Middleware component).

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. The user is provided with the SystemClock_Config()
function to configure the system clock (SYSCLK) to run at 168 MHz. The Full Speed (FS) USB module uses
internally a 48-MHz clock, which is generated from an integrated PLL. In the High Speed (HS) mode the
USB clock (60 MHz) is driven by the ULPI.

It's worth noting that the system clock (SYSCLK) can be configured, depending on the used USB Core:
 - SYSCLK is set to 168 MHz: for FS Core because used embedded PHY requires 48 MHz clock,
                             achieved only when system clock is set to 168 MHz.                             
 - SYSCLK is set to 180 MHz: for only HS Core, since no embedded PHY is used.
 
When the application is started, the connected USB flash disk device is detected in MSC mode and gets 
initialized. The STM32 MCU behaves as a MSC Host, it enumerates the device and extracts VID, PID, 
manufacturer name, Serial no and product name information and displays it on the LCD screen. 
This application is based on read/write file and explore the USB flash disk content. It creates a normal
priority thread, that executes a MSC routine.

A menu is displayed and the user can select any operation from the menu using the Joystick buttons:
 - "File Operations" operation writes a small text file (less to 1 KB) on the USB flash disk.
 - "Explorer Disk" operation explores the USB flash disk content and displays it on the LCD screen.
    User has to press the Key button to display the whole USB flash disk content (recursion level 2).
 - "Re-Enumerate" operation performs a new Enumeration of the device.

@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 USB Library Configuration

To select the appropriate USB Core to work with, user must add the following macro defines within the
compiler preprocessor (already done in the preconfigured projects provided with this example):
      - "USE_USB_HS" when using USB High Speed (HS) Core
      - "USE_USB_FS" when using USB Full Speed (FS) Core 

It is possible to fine tune needed USB Host features by modifying defines values in USBH configuration
file usbh_conf.h available under the project includes directory, in a way to fit the application
requirements, such as:
- Level of debug: USBH_DEBUG_LEVEL
                  0: No debug messages
                  1: Only User messages are shown
                  2: User and Error messages are shown
                  3: All messages and internal debug messages are shown
   By default debug messages are displayed on the debugger IO terminal; to redirect the Library
   messages on the LCD screen, lcd_log.c driver need to be added to the application sources.

Since this is an RTOS based example, built around FreeRTOS and CMSIS-OS wrapping layer common APIs,
the RTOS is enabled by setting, #define USBH_USE_OS      1


@par Directory contents

  - USB_Host/MSC_RTOS/Src/main.c                  Main program
  - USB_Host/MSC_RTOS/Src/system_stm32f4xx.c      STM32F4xx system clock configuration file
  - USB_Host/MSC_RTOS/Src/stm32f4xx_it.c          Interrupt handlers
  - USB_Host/MSC_RTOS/Src/menu.c                  MSC State Machine
  - USB_Host/MSC_RTOS/Src/usbh_conf.c             General low level driver configuration
  - USB_Host/MSC_RTOS/Src/explorer.c              Explore the USB flash disk content
  - USB_Host/MSC_RTOS/Src/file_operations.c       Write/read file on the disk
  - USB_Host/MSC_RTOS/Src/usbh_diskio.c           USB diskio interface for FatFs
  - USB_Host/MSC_RTOS/Inc/main.h                  Main program header file
  - USB_Host/MSC_RTOS/Inc/stm32f4xx_it.h          Interrupt handlers header file
  - USB_Host/MSC_RTOS/Inc/lcd_log_conf.h          LCD log configuration file
  - USB_Host/MSC_RTOS/Inc/stm32f4xx_hal_conf.h    HAL configuration file
  - USB_Host/MSC_RTOS/Inc/FreeRTOSConfig.h        FreeRTOS Module Configuration file
  - USB_Host/MSC_RTOS/Inc/usbh_conf.h             USB Host driver Configuration file
  - USB_Host/MSC_RTOS/Inc/ffconf.h                FatFs Module Configuration file
 

@par Hardware and Software environment

  - This example runs on STM32F407xx/STM32F417xx 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 RevC 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>
 */
 