stm32f407 dma hal 存储器到存储器

### STM32F407 HAL DMA Memory to Memory Transfer Example To implement a DMA memory-to-memory transfer using the HAL library on an STM32F407 microcontroller, several steps must be followed carefully. The configuration involves setting up the DMA controller and configuring it specifically for memory-to-memory transfers. #### Configuration of DMA Controller Firstly, ensure that the necessary files are included in your project such as `stm32f4xx_hal_dma.c` which contains all functions required for managing Direct Memory Access (DMA). Additionally, include header files like `stm32f4xx_hal.h`, ensuring proper initialization of peripherals through CubeMX or manual setup[^1]. The following code snippet demonstrates how to configure and start a simple memory-to-memory DMA transfer: ```c #include "stm32f4xx_hal.h" // Define source and destination buffers with some data. uint32_t srcBuff[] = {0x01, 0x02, 0x03}; uint32_t destBuff[3]; void SystemClock_Config(void); static void MX_DMA_Init(void); int main(void) { /* Reset of all peripherals, Initializes the Flash interface and Systick */ HAL_Init(); /* Configure the system clock */ SystemClock_Config(); // Initialize DMA MX_DMA_Init(); // Create handle structure for DMA Stream static DMA_HandleTypeDef hdma_memtomem; __HAL_RCC_DMA2_CLK_ENABLE(); // Enable DMA2 Clock // Fill parameters needed by HAL function hdma_memtomem.Instance = DMA2_Stream0; hdma_memtomem.Init.Channel = DMA_CHANNEL_0; hdma_memtomem.Init.Direction = DMA_MEMORY_TO_MEMORY; hdma_memtomem.Init.PeriphInc = DMA_PINC_DISABLE; hdma_memtomem.Init.MemInc = DMA_MINC_ENABLE; hdma_memtomem.Init.PeriphDataAlignment = DMA_PDATAALIGN_WORD; hdma_memtomem.Init.MemDataAlignment = DMA_MDATAALIGN_WORD; hdma_memtomem.Init.Mode = DMA_NORMAL; hdma_memtomem.Init.Priority = DMA_PRIORITY_HIGH; hdma_memtomem.Init.FIFOMode = DMA_FIFOMODE_DISABLE; hdma_memtomem.Init.FIFOThreshold = DMA_FIFO_THRESHOLD_HALFFULL; hdma_memtomem.Init.MemBurst = DMA_MBURST_SINGLE; hdma_memtomem.Init.PeriphBurst = DMA_PBURST_SINGLE; if(HAL_DMA_Init(&hdma_memtomem) != HAL_OK){ Error_Handler(__FILE__, __LINE__); } // Start DMA transfer from SRAM to another location within SRAM if(HAL_DMA_Start_IT(&hdma_memtomem, (uint32_t)&srcBuff, (uint32_t)&destBuff, sizeof(srcBuff)/sizeof(uint32_t))!= HAL_OK){ Error_Handler(__FILE__, __LINE__); } } /** * @brief This function handles DMA stream interrupts. */ void DMA2_Stream0_IRQHandler(void) { HAL_DMA_IRQHandler(&hdma_memtomem); } ``` In this example, two arrays (`srcBuff` and `destBuff`) represent the source and destination buffers respectively. A DMA channel is configured where both peripheral incrementing mode (`PeriphInc`) and memory incrementing modes (`MemInc`) need appropriate settings depending upon whether addresses should increase during each transaction. For memory-to-memory operations typically only one side needs increasing while other remains fixed. Additionally, interrupt handling has been set up so that once the operation completes successfully, corresponding flags can trigger actions defined inside `DMA2_Stream0_IRQHandler`. --related questions-- 1. How does enabling/disabling FIFO affect performance when performing large block transfers? 2. What precautions should be taken into account regarding buffer sizes relative to available RAM space? 3. Can you explain more about different priority levels assigned to streams? 4. Is there any difference between single burst versus multi-burst configurations? 5. Are there specific conditions under which circular buffering might prove beneficial over normal mode?