带DMA的SPI回送

Question

我正在使用STM32F4发现板，而我正在尝试通过DMA来获得SPI回送。我成功地获得了一个“SPI专用”环回运行，但是现在我想在SPI之外使用DMA，下面是正在使用的函数：

SPI编辑的初始化

void init_SPI1(void){    
  NVIC_InitTypeDef NVIC_InitStructure;
  GPIO_InitTypeDef GPIO_InitStruct;
  SPI_InitTypeDef SPI_InitStruct ;

  RCC_AHB1PeriphClockCmd(RCC_AHB1Periph_GPIOA, ENABLE);

  GPIO_InitStruct.GPIO_Pin = GPIO_Pin_7 | GPIO_Pin_6 | GPIO_Pin_5|GPIO_Pin_4;
  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_PinSource4, GPIO_AF_SPI1);
  GPIO_PinAFConfig(GPIOA, GPIO_PinSource5, GPIO_AF_SPI1);
  GPIO_PinAFConfig(GPIOA, GPIO_PinSource6, GPIO_AF_SPI1);
  GPIO_PinAFConfig(GPIOA, GPIO_PinSource7, GPIO_AF_SPI1);

  //Set chip select high 
  GPIOA->BSRRL |= GPIO_Pin_4; // set PA4 high

  // enable SPI1 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_StructInit(&SPI_InitStruct); // set default settings 
  SPI_InitStruct.SPI_Direction = SPI_Direction_2Lines_FullDuplex; // set to full duplex mode, seperate MOSI and MISO lines
  SPI_InitStruct.SPI_Mode = SPI_Mode_Master;     // transmit in master mode, NSS pin has to be always high
  SPI_InitStruct.SPI_DataSize = SPI_DataSize_8b; // one packet of data is 8 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 ; // set the NSS management to internal and pull internal NSS high
  SPI_InitStruct.SPI_BaudRatePrescaler = SPI_BaudRatePrescaler_4; // SPI frequency is APB2 frequency / 4
  SPI_InitStruct.SPI_FirstBit = SPI_FirstBit_MSB;// data is transmitted MSB first
  SPI_Init(SPI1, &SPI_InitStruct); 

  NVIC_InitStructure.NVIC_IRQChannel = SPI1_IRQn;
  NVIC_InitStructure.NVIC_IRQChannelPreemptionPriority = 1;
  NVIC_InitStructure.NVIC_IRQChannelSubPriority = 1;
  NVIC_InitStructure.NVIC_IRQChannelCmd = ENABLE;
  NVIC_Init(&NVIC_InitStructure);  

  SPI_I2S_ITConfig(SPI1,SPI_I2S_IT_RXNE,ENABLE);
  return;
}        

DMA编辑的配置

void DMA_Config()
{  
DMA_InitTypeDef DMA_InitStructure;   
NVIC_InitTypeDef NVIC_InitStructure;

RCC_AHB1PeriphClockCmd(RCC_AHB1Periph_DMA2, ENABLE);

DMA_ClearFlag(DMA2_Stream5,        DMA_FLAG_FEIF2|DMA_FLAG_DMEIF2|DMA_FLAG_TEIF2|DMA_FLAG_HTIF2|DMA_FLAG_TCIF2);
DMA_Cmd(DMA2_Stream5, DISABLE);
while (DMA2_Stream5->CR & DMA_SxCR_EN);
DMA_DeInit(DMA2_Stream5);
DMA_StructInit(&DMA_InitStructure);

DMA_InitStructure.DMA_Channel = DMA_Channel_3;
DMA_InitStructure.DMA_PeripheralBaseAddr  = (uint32_t) &(SPI1->DR);
DMA_InitStructure.DMA_Memory0BaseAddr  = (uint32_t) &spiTxBuff;
DMA_InitStructure.DMA_DIR = DMA_DIR_MemoryToPeripheral;
DMA_InitStructure.DMA_BufferSize  = SPI_TX_MAX;
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_Disable;

DMA_Init(DMA2_Stream5, &DMA_InitStructure); 

/**
configuration of the interrupts of DMA
******************************************************/
DMA_ITConfig(DMA2_Stream5, DMA_IT_TC, ENABLE);
NVIC_InitStructure.NVIC_IRQChannel = DMA2_Stream5_IRQn;
NVIC_InitStructure.NVIC_IRQChannelPreemptionPriority = 1;
NVIC_InitStructure.NVIC_IRQChannelSubPriority = 2;
NVIC_InitStructure.NVIC_IRQChannelCmd = ENABLE;
NVIC_Init(&NVIC_InitStructure);  
return;
}

SPI写函数：

void SPI1_Write(uint8_t *txBuff,int length,tSPI_Callback fct)
{
 DMA2_Stream5->M0AR = (uint32_t) &spiTxBuff;
 DMA_Cmd(DMA2_Stream5, ENABLE);
 SPI_I2S_DMACmd(SPI1, SPI_I2S_DMAReq_Tx, ENABLE);
 SPI_Cmd(SPI1, ENABLE);
}

接收到的数据使用spi中断处理程序写在Rx缓冲区中。

void SPI1_IRQHandler()
{
 spiRxBuff[spiRxCount] = SPI_I2S_ReceiveData(SPI1);
 spiRxCount++;
}

我主要是这样调用这些函数的：

C.主要：

DMA_Config();
init_SPI1();
SPI1_Write(spiTxBuff,SPI_TX_MAX,(void*)0); 

使用调试器我发现，在DMA高中断状态寄存器中，TCIF5(传输完全标志)和HTIF5(半传输完全标志)被设置为1，这意味着在我看来，传输是成功的，但是在SPI缓冲区中没有得到任何数据，第二个奇怪的事情是，未触发DMA中断或SPI中断。你能帮我找出我的代码有什么问题吗？

编辑

DMA和SPI中断被触发，但现在的问题是我不能接收所有的元素，只能接收第一个

uint8_t spiTxBuff[SPI_TX_MAX] = {0x01,0x02,0x03,0x04,0x05,0x06,0x07,0x08,0x09,0x10};

但spiRxBuff[SPI_RX_MAX] ={0x01,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00}

这个问题是因为DMA比中断处理程序快，所以SPI中断处理程序没有时间处理所有接收到的数据吗？

Answer 1

• 正如kkrambo所指出的，您正在为DMA1而不是DMA2启用中断。不要忘记在那里安装一个中断处理程序。
• DMA2_Stream2是怎么回事？
• SPI中断显然没有配置(或者我找不到位置)。喜欢：SPI_I2S_ITConfig(SPI1,SPI_I2S_IT_RXNE,ENABLE);

Answer 2

确保在SPI中没有读取接收到的字节，如果这样做会导致DMA找不到要复制的字节。我的意思是，DMA和SPI是试图读取同一个缓冲区的两个资源，您不知道哪个资源会首先读取字节。此外，DMA工作时，仍然是SPI ISR旗帜升起，如果SPI读取这个标志将被清除，导致DMA将无法工作。