SPI主机DMA接收数据出错是什么原因

阿成HAC · 发表于 2017-8-10 13:40:41

我用的是STM32F103C8T6，设置SPI为主机，DMA接收方式，左图是轮询读到正确的数据，右图是DMA接收错误的数据

初始化代码：
SPI_InitStructure.SPI_Direction = SPI_Direction_2Lines_FullDuplex;
SPI_InitStructure.SPI_Mode = SPI_Mode_Master;
SPI_InitStructure.SPI_DataSize = SPI_DataSize_8b; //8bit
SPI_InitStructure.SPI_CPOL = SPI_CPOL_Low;
SPI_InitStructure.SPI_CPHA = SPI_CPHA_2Edge;
SPI_InitStructure.SPI_NSS = SPI_NSS_Soft;
SPI_InitStructure.SPI_BaudRatePrescaler = SPI_BaudRatePrescaler_16; //4.5MHZ
SPI_InitStructure.SPI_FirstBit = SPI_FirstBit_MSB;
SPI_InitStructure.SPI_CRCPolynomial = 7;
SPI_Init(SPI1, &SPI_InitStructure);
SPI_NSSInternalSoftwareConfig(SPI1,  SPI_NSSInternalSoft_Set);

SPI_I2S_DMACmd(SPI1, SPI_I2S_DMAReq_Rx, ENABLE);
SPI_I2S_DMACmd(SPI1, SPI_I2S_DMAReq_Tx, ENABLE);

      RCC_AHBPeriphClockCmd(RCC_AHBPeriph_DMA1, ENABLE);

DMA_InitStructure.DMA_PeripheralBaseAddr = (uint32_t)&(SPI1->DR);
DMA_InitStructure.DMA_MemoryBaseAddr = (uint32_t)EcgBuff;
DMA_InitStructure.DMA_DIR = DMA_DIR_PeripheralSRC;
DMA_InitStructure.DMA_BufferSize = 0;
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_VeryHigh;
DMA_InitStructure.DMA_M2M = DMA_M2M_Disable;
DMA_Init(DMA1_Channel2, &DMA_InitStructure);

DMA_Cmd(DMA1_Channel2, DISABLE);

DMA_InitStructure.DMA_MemoryBaseAddr = (uint32_t)DummyClock;
DMA_InitStructure.DMA_DIR = DMA_DIR_PeripheralDST;
DMA_InitStructure.DMA_Priority = DMA_Priority_Low;
DMA_Init(DMA1_Channel3, &DMA_InitStructure);
DMA_Cmd(DMA1_Channel3, DISABLE);

DMA_ITConfig(DMA1_Channel2, DMA_IT_TC, ENABLE);
DMA_ITConfig(DMA1_Channel3, DMA_IT_TC, ENABLE);

DMA读取len字节
void  SPIReadBuf(uint8_t *buf, uint16_t len)
{
DMA_Cmd(DMA1_Channel2, DISABLE);
DMA_Cmd(DMA1_Channel3, DISABLE);
DMA1_Channel2->CNDTR = len;
DMA1_Channel3->CNDTR = len;
SPI1->DR;
DMA_Cmd(DMA1_Channel2, ENABLE);
DMA_Cmd(DMA1_Channel3, ENABLE);

}