STM32CubeF7/Projects/STM32F7508-DISCO/Examples/GPIO/GPIO_IOToggle/readme.txt

/**
  @page GPIO_IOToggle GPIO IO Toggle example
  
  @verbatim
  ******************************************************************************
  * @file    GPIO/GPIO_IOToggle/readme.txt 
  * @author  MCD Application Team
  * @brief   Description of the GPIO IO Toggle example.
  ******************************************************************************
  * @attention
  *
  * <h2><center>&copy; Copyright (c) 2018 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

How to configure and use GPIOs through the HAL API. 

This example provide different configuration with linker files which allows different eXecution schemas
Supported configuration by STM32F7508-DISCO:
  - XiP From QSPI, Data on Internal SRAM
  - XiP From QSPI, Data on External SDRAM
  - BootROM : Execution From External SDRAM , Data on Internal SRAM
  
PI1 IO (configured in output pushpull mode) toggles in a forever loop.
On STM32F7508-DISCO board this IO is connected to LED1.

In this example, HCLK is configured at 216 MHz.

@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

System, GPIO, Output, Alternate function, Push-pull, Toggle

@Note<74>If the user code size exceeds the DTCM-RAM size or starts from internal cacheable memories (SRAM1 and SRAM2),that is shared between several processors,
 <20><><EFBFBD><EFBFBD><EFBFBD>then it is highly recommended to enable the CPU cache and maintain its coherence at application level.
<EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>The address and the size of cacheable buffers (shared between CPU and other masters)  must be properly updated to be aligned to cache line size (32 bytes).

@Note It is recommended to enable the cache and maintain its coherence, but depending on the use case
<EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD> It is also possible to configure the MPU as "Write through", to guarantee the write access coherence.
<EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>In that case, the MPU must be configured as Cacheable/Bufferable/Not Shareable.
<EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>Even though the user must manage the cache coherence for read accesses.
<EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>Please refer to the AN4838 <20>Managing memory protection unit (MPU) in STM32 MCUs<55>
<EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>Please refer to the AN4839 <20>Level 1 cache on STM32F7 Series<65>

@par Directory contents 

  - GPIO/GPIO_IOToggle/Inc/stm32f7xx_hal_conf.h    HAL configuration file
  - GPIO/GPIO_IOToggle/Inc/stm32f7xx_it.h          Interrupt handlers header file
  - GPIO/GPIO_IOToggle/Inc/main.h                  Header for main.c module  
  - GPIO/GPIO_IOToggle/Src/stm32f7xx_it.c          Interrupt handlers
  - GPIO/GPIO_IOToggle/Src/main.c                  Main program
  - GPIO/GPIO_IOToggle/Src/system_stm32f7xx.c      STM32F7xx system source file


@par Hardware and Software environment

  - This example runs on STM32F7508xx devices.
    
  - This example has been tested with STM32F7508-DISCO 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:

  1. Select required configuration in memory.h in Templates\ExtMem_Boot\Inc.
     The default configuration is: 
     - DATA_AREA set to USE_INTERNAL_SRAM
     - CODE_AREA set to USE_QSPI
  2. Program the internal Flash with the ExtMem_Boot (see below).
  3. Program the external memory with your application (see below).
  4. Start debugging user application or reset for free running.

In order to load the ExtMem_Boot code :
   - Open your preferred toolchain :
      - Open the Project
      - Rebuild all files
      - Load project image

In order to load the user application to the external memory:
   - Open your preferred toolchain
      - Open the Project
      - Use project matching ExtMem_Boot selected configuration
      - Rebuild all files:
      - Run & debug the program:
      - For an XiP configuration (eXecute in Place from QSPI):
          - Using EWARM or MDK-ARM : Load project image from the IDE: Project->Debug
          - Using SW4STM32 :
            - Open the STM32CubeProgrammer tool
            - Select the QSPI external flash loader "N25Q128A_STM32F7508-DISCO" in case of XiP from QSPI
            - From Erasing & Programming menu, browse and open the output binary file relative to the application
            - Load the file into the external QSPI flash using "Start Programming" at the address APPLICATION_ADDRESS (0x90000000)

      - For a BootROM configuration (BootROM external SDRAM):
        - if BINARY_AREA is USE_SPI_NOR then use the STM32CubeProgarmmer tool, select QSPI external flash loader "N25Q128A_STM32F7508-DISCO"
          and load the Project.bin (application binary output file) to the QSPI memory at the address 0x90000000
        - if BINARY_AREA is USE_SDCARD then copy the project.bin to a micro-SD to be plugged on CN3 and reset the board.
        - In order to debug this example, user shall attach the debugger, and perform a reset


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