STM32CubeF4

@verbatim
******************** (C) COPYRIGHT 2017 STMicroelectronics *******************
* @file FMC/FMC_PSRAM/readme.txt
* @author MCD Application Team
* @brief Description of the FMC PSRAM example.
******************************************************************************
*
* Copyright (c) 2017 STMicroelectronics. All rights reserved.
*
* 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

This example describes how to configure the FMC controller to access the PSRAM
memory.

The PSRAM is IS66WV51216EBLL-55BLI.

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 100 MHz.

The goal of this example is to explain the different steps to configure the FMC
and make the PSRAM device ready for access, without using the MSP layer.

In this example, the SRAM device is configured and initialized explicitly
following all initialization sequence steps. After initializing the device, user
can perform read/write operations on it. A data buffer is written to the PSRAM
memory, then read back and checked to verify its correctness.

If the data is read correctly from PSRAM, the LED3 is ON, otherwise the LED4 is ON.
In case of HAL initialization issue, LED4 will be ON.

@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 Keywords

Memory, FMC, PSRAM, Read, Write, Initialization, Access

@par Directory contents

- FMC/FMC_PSRAM/Inc/stm32f4xx_hal_conf.h HAL Configuration file
- FMC/FMC_PSRAM/Inc/main.h Header for main.c module
- FMC/FMC_PSRAM/Inc/stm32f4xx_it.h Header for stm32f4xx_it.c
- FMC/FMC_PSRAM/Src/main.c Main program
- FMC/FMC_PSRAM/Src/stm32f4xx_hal_msp.c HAL MSP module
- FMC/FMC_PSRAM/Src/stm32f4xx_it.c Interrupt handlers
- FMC/FMC_PSRAM/Src/system_stm32f4xx.c STM32F4xx system clock configuration file

@par Hardware and Software environment

- This example runs on STM32F413xx/STM32F423xx devices.

- This example has been tested with STM32F413H-Discovery board and can be
easily tailored to any other supported device and development board.

@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