/**
@page QSPI_PreInitConfig QSPI pre-init configuration example
@verbatim
******************** (C) COPYRIGHT 2017 STMicroelectronics *******************
* @file QSPI/QSPI_PreInitConfig/readme.txt
* @author MCD Application Team
* @brief Description of the code execution from QSPI memory example.
******************************************************************************
* @attention
*
* Copyright (c) 2017 STMicroelectronics.
* All rights reserved.
*
* This software is licensed under terms that can be found in the LICENSE file
* in the root directory of this software component.
* If no LICENSE file comes with this software, it is provided AS-IS.
*
******************************************************************************
@endverbatim
@par Example Description
How to configure the QSPI IP in order to have access to external memory just after reset.
This example describes how to execute a part of the code from a QSPI memory. To do this,
a section is created where the function is stored.
The QSPI is configured in memory-mapped mode before to call main() function and QSPI memory
is then available after the reset.
The configuration of the QSPI is done in the file system_stm32f4xx.c file in the
function SystemInit_ExtMemCtl(). It is called by the function SystemInit(), which
is the first function called by the Reset_Handler.
The code in executed in a forever loop. It is the same code as GPIO_IOToggle example
with some code mapped in QSPI mode and other in Flash, to show the jump from one
memory to the other.
LED1, LED2, LED3 and LED4 toggle in this forever loop.
In this example, HCLK is configured at 180 MHz.
@note In order to account for external signal delays, SampleShifting parameter should be set to
HALFCYCLE. This bit allows the data is to be sampled correctly at 90MHZ. Otherwise
Read operation will not work at frequency greater than 60MHz.
@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, QUADSPI, Erase, Write, DMA, section, memory-mapped mode, PreInit configuration, Jump
@par Directory contents
- QSPI/QSPI_PreInitConfig/Inc/stm32f4xx_hal_conf.h HAL configuration file
- QSPI/QSPI_PreInitConfig/Inc/stm32f4xx_it.h Interrupt handlers header file
- QSPI/QSPI_PreInitConfig/Inc/main.h Header for main.c module
- QSPI/QSPI_PreInitConfig/Src/stm32f4xx_it.c Interrupt handlers
- QSPI/QSPI_PreInitConfig/Src/main.c Main program
- QSPI/QSPI_PreInitConfig/Src/system_stm32f4xx.c STM32F4xx system source file
- QSPI/QSPI_PreInitConfig/Src/stm32f4xx_hal_msp.c HAL MSP file
@par Hardware and Software environment
- This example runs on STM32F446xx devices.
- This example has been tested with STM32446E-EVAL board and can be
easily tailored to any other supported device and development board.
- STM32446E-EVAL Set-up :
Make sure that board is configured for QuadSPI memory interface as
described in MB1162_UM.pdf
- A specific region for the QSPI memory has been added in the scatter file (STM32F446xx_flash.icf for IAR toolchain,
STM32446E-EVAL.sct for MDK-ARM toolchain, STM32F446ZETx_FLASH.ld for STM32CubeIDE toolchain) in order to map functions in this memory
@par How to use it ?
In order to make the program work, you must do the following :
- Open your preferred toolchain
- Rebuild all files
- Load your image into target memory with ST-Link Utility and external loader N25Q256A_STM32F446E-EVAL
-> !!! Be careful, don't try to use the toolchain to load the image, it is not able to load some code in QSPI memory !!!
- Run the example
*/
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