spi dma flash程序

SPI DMA FLASH程序通常用于在单片机中使用SPI接口与闪存进行数据传输。DMA（直接内存访问）可以大大提高数据传输的效率，因为它允许数据在不占用CPU时间的情况下直接从外设传输到内存中。

以下是一个基于STM32F4的SPI DMA FLASH程序示例：

#include "stm32f4xx.h"
#include "stm32f4xx_spi.h"
#include "stm32f4xx_dma.h"
#include "stm32f4xx_flash.h"

#define FLASH_START_ADDRESS   0x08000000
#define FLASH_SECTOR_SIZE     0x1000
#define BUFFER_SIZE           256

uint8_t tx_buffer[BUFFER_SIZE];
uint8_t rx_buffer[BUFFER_SIZE];

void SPI_DMA_Configuration(void)
{
    SPI_InitTypeDef  SPI_InitStructure;
    DMA_InitTypeDef  DMA_InitStructure;

    RCC_AHB1PeriphClockCmd(RCC_AHB1Periph_DMA1, ENABLE);
    RCC_APB2PeriphClockCmd(RCC_APB2Periph_SPI1, ENABLE);

    DMA_DeInit(DMA1_Stream4);
    DMA_InitStructure.DMA_Channel = DMA_Channel_3;
    DMA_InitStructure.DMA_PeripheralBaseAddr = (uint32_t)&SPI1->DR;
    DMA_InitStructure.DMA_Memory0BaseAddr = (uint32_t)rx_buffer;
    DMA_InitStructure.DMA_DIR = DMA_DIR_PeripheralToMemory;
    DMA_InitStructure.DMA_BufferSize = BUFFER_SIZE;
    DMA_InitStructure.DMA_PeripheralInc = DMA_PeripheralInc_Disable;
    DMA_InitStructure.DMA_MemoryInc = DMA_MemoryInc_Enable;
    DMA_InitStructure.DMA_PeripheralDataSize = DMA_PeripheralDataSize_Byte;
    DMA_InitStructure.DMA_MemoryDataSize = DMA_MemoryDataSize_Byte;
    DMA_InitStructure.DMA_Mode = DMA_Mode_Normal;
    DMA_InitStructure.DMA_Priority = DMA_Priority_High;
    DMA_InitStructure.DMA_FIFOMode = DMA_FIFOMode_Enable;
    DMA_InitStructure.DMA_FIFOThreshold = DMA_FIFOThreshold_HalfFull;
    DMA_InitStructure.DMA_MemoryBurst = DMA_MemoryBurst_Single;
    DMA_InitStructure.DMA_PeripheralBurst = DMA_PeripheralBurst_Single;
    DMA_Init(DMA1_Stream4, &DMA_InitStructure);

    SPI_I2S_DeInit(SPI1);
    SPI_InitStructure.SPI_Direction = SPI_Direction_2Lines_FullDuplex;
    SPI_InitStructure.SPI_Mode = SPI_Mode_Master;
    SPI_InitStructure.SPI_DataSize = SPI_DataSize_8b;
    SPI_InitStructure.SPI_CPOL = SPI_CPOL_Low;
    SPI_InitStructure.SPI_CPHA = SPI_CPHA_1Edge;
    SPI_InitStructure.SPI_NSS = SPI_NSS_Soft;
    SPI_InitStructure.SPI_BaudRatePrescaler = SPI_BaudRatePrescaler_16;
    SPI_InitStructure.SPI_FirstBit = SPI_FirstBit_MSB;
    SPI_InitStructure.SPI_CRCPolynomial = 7;
    SPI_Init(SPI1, &SPI_InitStructure);

    SPI_I2S_DMACmd(SPI1, SPI_I2S_DMAReq_Rx, ENABLE);

    DMA_Cmd(DMA1_Stream4, ENABLE);

    SPI_Cmd(SPI1, ENABLE);
}

void FLASH_EraseSector(uint32_t sectorAddr)
{
    FLASH_Status status;
    FLASH_Unlock();
    status = FLASH_EraseSector(sectorAddr, VoltageRange_3);
    FLASH_Lock();
}

void FLASH_WriteData(uint32_t addr, uint8_t *data, uint32_t len)
{
    FLASH_Status status;
    uint32_t i;
    uint16_t *pData = (uint16_t *)data;

    FLASH_Unlock();

    for (i = 0; i < len / 2; i++)
    {
        status = FLASH_ProgramHalfWord(addr, *pData++);
        addr += 2;
    }

    FLASH_Lock();
}

int main(void)
{
    uint32_t i;
    uint32_t flashAddr = FLASH_START_ADDRESS;

    for (i = 0; i < BUFFER_SIZE; i++)
    {
        tx_buffer[i] = i;
        rx_buffer[i] = 0;
    }

    SPI_DMA_Configuration();

    // Erase the first sector of flash memory
    FLASH_EraseSector(FLASH_START_ADDRESS);

    // Write the data to flash memory
    FLASH_WriteData(flashAddr, tx_buffer, BUFFER_SIZE);

    // Verify the data
    for (i = 0; i < BUFFER_SIZE; i++)
    {
        if (rx_buffer[i] != tx_buffer[i])
        {
            // Error occurred
            while (1);
        }
    }

    // Data transfer successful
    while (1);
}

在这个程序中，我们首先配置了SPI和DMA，然后使用DMA将数据从SPI接收到的缓冲区传输到内存中。接下来，我们使用FLASH_EraseSector函数擦除了闪存的第一个扇区，并使用FLASH_WriteData函数将数据写入闪存。最后，我们从闪存中读取数据并与原始数据进行比较以验证数据传输的正确性。