stm32 DMA cannot send data to SPI1 DR(无法使用DMA向SPI发送数据)

Question

我正在尝试使用 DMA 将数据发送到 SPI1。然后 SPI1 将控制 DAC 进行电压更新。

使用的芯片是STM32F407。因此对应的channel/stream为:channel3/stream5，引用手册中有说明。但是，当启用 DMA 时，SPI1->DR 中没有数据显示，示波器中也没有显示结果。

当 SPI1->DR 由软件写入时，SPI 工作正常。谁能帮忙看看是怎么回事？代码来了:

uint16_t DACData[1]; 
void InitDMA(void)
{
    DMA_InitTypeDef DMA_InitStructure;
    DMA_Cmd(DMA2_Stream2, DISABLE);
    while (DMA2_Stream2->CR & DMA_SxCR_EN);
    //SPI1 Tx DMA
    DMA_DeInit(DMA2_Stream5);
    DMA_StructInit(&DMA_InitStructure);
    RCC_AHB1PeriphClockCmd(RCC_AHB1Periph_DMA2, ENABLE); //Init DMA clock
    DMA_InitStructure.DMA_Channel = DMA_Channel_3;//SPI1 Tx 
    DMA_InitStructure.DMA_PeripheralBaseAddr  = (uint32_t)&(SPI1->DR); //Set the SPI1 Tx
    DMA_InitStructure.DMA_Memory0BaseAddr  = (uint32_t)&DACData;       //Set the memory location
    DMA_InitStructure.DMA_DIR  = DMA_DIR_MemoryToPeripheral;           //
    DMA_InitStructure.DMA_BufferSize  = 1;            //Define the number of bytes to send
    DMA_InitStructure.DMA_PeripheralInc  = DMA_PeripheralInc_Disable;             
    DMA_InitStructure.DMA_MemoryInc  = DMA_MemoryInc_Disable;            
    DMA_InitStructure.DMA_PeripheralDataSize  = DMA_PeripheralDataSize_HalfWord;    
    DMA_InitStructure.DMA_MemoryDataSize  = DMA_PeripheralDataSize_HalfWord;        
    DMA_InitStructure.DMA_Mode  = DMA_Mode_Normal;               //Normal mode (not circular)
    DMA_InitStructure.DMA_Priority  = DMA_Priority_High;                
    DMA_InitStructure.DMA_FIFOMode  = DMA_FIFOMode_Disable;  //Operate in 'direct mode' 
    DMA_InitStructure.DMA_MemoryBurst =DMA_MemoryBurst_Single;
    DMA_InitStructure.DMA_PeripheralBurst =DMA_PeripheralBurst_Single;
    DMA_Init(DMA2_Stream5, &DMA_InitStructure); //DMA2, Channel 3, stream 5

    //Enable the transfer complete interrupt for DMA2 Stream5
    DMA_ITConfig(DMA2_Stream5, DMA_IT_TC, ENABLE);                                       
}

这是SPI1的初始化方式

void InitSPI1(void) 
 {
    GPIO_InitTypeDef GPIO_InitStruct;
    SPI_InitTypeDef SPI_InitStruct;
    // enable clock for used IO pins
    RCC_AHB1PeriphClockCmd(RCC_AHB1Periph_GPIOA, ENABLE);
    GPIO_InitStruct.GPIO_Pin = GPIO_Pin_7 | GPIO_Pin_6 | GPIO_Pin_5;
    GPIO_InitStruct.GPIO_Mode = GPIO_Mode_AF;
    GPIO_InitStruct.GPIO_OType = GPIO_OType_PP;
    GPIO_InitStruct.GPIO_Speed = GPIO_Speed_50MHz;
    GPIO_InitStruct.GPIO_PuPd = GPIO_PuPd_NOPULL;
    GPIO_Init(GPIOA, &GPIO_InitStruct);

    // connect SPI1 pins to SPI alternate function
    GPIO_PinAFConfig(GPIOA, GPIO_PinSource5, GPIO_AF_SPI1); //SCK
    GPIO_PinAFConfig(GPIOA, GPIO_PinSource6, GPIO_AF_SPI1); //MISO
    GPIO_PinAFConfig(GPIOA, GPIO_PinSource7, GPIO_AF_SPI1); //MOSI
    // enable peripheral clock
    RCC_APB2PeriphClockCmd(RCC_APB2Periph_SPI1, ENABLE);

    /* configure SPI1 in Mode 0 
     * CPOL = 0 --> clock is low when idle
     * CPHA = 0 --> data is sampled at the first edge
     */
    SPI_InitStruct.SPI_Direction = SPI_Direction_1Line_Tx; // one line transmission
    SPI_InitStruct.SPI_Mode = SPI_Mode_Master;     // transmit in master mode, NSS pin has to be always high
    SPI_InitStruct.SPI_DataSize = SPI_DataSize_16b; // one packet of data is 16 bits wide
    SPI_InitStruct.SPI_CPOL = SPI_CPOL_Low;        // clock is low when idle
    SPI_InitStruct.SPI_CPHA = SPI_CPHA_1Edge;      // data sampled at first edge
    SPI_InitStruct.SPI_NSS = SPI_NSS_Soft | SPI_NSSInternalSoft_Set;; // set the NSS management to hardware
    SPI_InitStruct.SPI_BaudRatePrescaler = SPI_BaudRatePrescaler_256; // SPI frequency is APB2 frequency / 4 = 21MHz
    SPI_InitStruct.SPI_FirstBit = SPI_FirstBit_MSB;// data is transmitted MSB first

    SPI_Init(SPI1, &SPI_InitStruct); 
    SPI_Cmd(SPI1, ENABLE); // enable SPI1
}

我尝试使用这些命令来启动 DMA:

DACData[0]=0xff00;
DMA_Cmd(DMA2_Stream5, ENABLE);

如果有帮助，这里是 DMA2、Stream 5 的寄存器值

Answer 1

漏掉了这样一行:

SPI_I2S_DMACmd(SPI1, SPI_I2S_DMAReq_Tx, 启用);

它使 SPI1 能够使用 DMA。