/**
@page DMA_FLASHToRAM DMA FLASH To RAM Example
@verbatim
******************************************************************************
* @file DMA/DMA_FLASHToRAM/readme.txt
* @author MCD Application Team
* @brief Description of the DMA FLASH to RAM example.
******************************************************************************
* @attention
*
* <h2><center>© 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 use a DMA to transfer a word data buffer from Flash memory to embedded
SRAM through the HAL API.
This projects is configured for STM32F750xx devices using STM32CubeF7 HAL and running on
STM32F7508-DISCO board from STMicroelectronics.
In this example, the code is executed from QSPI external memory while data are in internal
SRAM memory.
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 216 MHz.
DMA2_Stream0 is configured to transfer the contents of a 32-word data
buffer stored in Flash memory to the reception buffer declared in RAM.
The start of transfer is triggered by software. DMA2_Stream0 memory-to-memory
transfer is enabled. Source and destination addresses incrementing is also enabled.
The transfer is started by setting the stream enable bit for DMA2_Stream0.
At the end of the transfer a Transfer Complete interrupt is generated since it
is enabled and the callback function (customized by user) is called.
STM32F7508-DISCO board's LEDs can be used to monitor the transfer status:
- LED1 is ON when the transfer is complete (into the Transfer Complete interrupt
routine).
- LED1 is Toggled with a period of 200 ms when there is a transfer error
It is possible to select a different stream for the DMA transfer
example by modifying defines values in the file main.h.
Note that only DMA2 stream are able to perform Memory-to-Memory transfers.
@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, DMA, Data Transfer, Memory to memory, Stream, Flash, RAM
@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><><A0><A0><A0>then it is highly recommended to enable the CPU cache and maintain its coherence at application level.
<0A><><A0><A0><A0><A0>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
<0A><><A0><A0><A0> It is also possible to configure the MPU as "Write through", to guarantee the write access coherence.
<0A><><A0><A0><A0><A0>In that case, the MPU must be configured as Cacheable/Bufferable/Not Shareable.
<0A><><A0><A0><A0><A0>Even though the user must manage the cache coherence for read accesses.
<0A><><A0><A0><A0><A0>Please refer to the AN4838 <20>Managing memory protection unit (MPU) in STM32 MCUs<55>
<0A><><A0><A0><A0><A0>Please refer to the AN4839 <20>Level 1 cache on STM32F7 Series<65>
@par Directory contents
- DMA/DMA_FLASHToRAM/Src/system_stm32f7xx.c STM32F7xx system clock configuration file
- DMA/DMA_FLASHToRAM/Src/stm32f7xx_it.c Interrupt handlers
- DMA/DMA_FLASHToRAM/Src/main.c Main program
- DMA/DMA_FLASHToRAM/Inc/stm32f7xx_hal_conf.h HAL Configuration file
- DMA/DMA_FLASHToRAM/Inc/stm32f7xx_it.h Interrupt handlers header file
- DMA/DMA_FLASHToRAM/Inc/main.h Main program header file
@par Hardware and Software environment
- This application runs on STM32F750xx devices.
- This application has been tested with STMicroelectronics STM32F7508-DISCO
boards 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 example (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 (this example) 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 this example
- Load the file into the external QSPI flash using "Start Programming" at the address APPLICATION_ADDRESS (0x90000000)
* <h3><center>© COPYRIGHT STMicroelectronics</center></h3>
*/
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