在我的项目中，我使用 Master SPI 通信从外部 ADC 获取模拟数据。我的MCU是STM32F746ZGTX。我的系统需要实时工作，所以我使用了 SPI DMA 接收和发送功能。
我在不使用 DMA 的情况下通过 SPI 轮询正确读取所有外部 ADC 数据。在 SPI 轮询中，我首先将控制字节发送到外部 ADC，此时程序正在while(SPI_Ready)循环等待，然后开始接收所有 ADC 数据。这种情况非常有效。
但我不想while(SPI_Ready)在每次 ADC 读数中循环等待。因为它影响我的实时计算。这就是我将功能切换到 DMA 的原因。
我的新算法如下所示：
- 使用下降沿触发生成外部 GPIO 中断，以检测外部 ADC 的数据就绪输出。
- 将片选引脚设为低电平以开始与外部 ADC 通信
HAL_SPI_Transmit_DMA()向具有功能的外部 ADC 发送读取命令。- 在
HAL_SPI_TxCpltCallback函数中，触发HAL_SPI_Receive_DMA() - 在
HAL_SPI_RxCpltCallback功能上，缓冲接收到的 ADC 数据并使片选引脚为高电平以终止通信。
当我使用这个算法时，我的 ADC 缓冲区中总是得到 0xFF 值。似乎即使 ADC 没有发送原始数据，由于触发接收 DMA，我的 MCU 发送时钟并将所有逻辑高信号作为接收数据。
我在下面分享我的代码。如果您有任何建议我错了，请分享您的意见。
/* SPI1 init function */
static void MX_SPI1_Init(void)
{
hspi1.Instance = SPI1;
hspi1.Init.Mode = SPI_MODE_MASTER;
hspi1.Init.Direction = SPI_DIRECTION_2LINES;
hspi1.Init.DataSize = SPI_DATASIZE_8BIT;
hspi1.Init.CLKPolarity = SPI_POLARITY_HIGH;
hspi1.Init.CLKPhase = SPI_PHASE_2EDGE;
hspi1.Init.NSS = SPI_NSS_SOFT;
hspi1.Init.BaudRatePrescaler = SPI_BAUDRATEPRESCALER_8;
hspi1.Init.FirstBit = SPI_FIRSTBIT_MSB;
hspi1.Init.TIMode = SPI_TIMODE_DISABLE;
hspi1.Init.CRCCalculation = SPI_CRCCALCULATION_DISABLE;
hspi1.Init.CRCPolynomial = 7;
hspi1.Init.CRCLength = SPI_CRC_LENGTH_DATASIZE;
hspi1.Init.NSSPMode = SPI_NSS_PULSE_DISABLE;
if (HAL_SPI_Init(&hspi1) != HAL_OK)
{
}
}
void HAL_SPI_MspInit(SPI_HandleTypeDef* hspi)
{
GPIO_InitTypeDef GPIO_InitStruct;
if(hspi->Instance==SPI1)
{
/* USER CODE BEGIN SPI1_MspInit 0 */
/* USER CODE END SPI1_MspInit 0 */
/* Peripheral clock enable */
__HAL_RCC_SPI1_CLK_ENABLE();
/**SPI1 GPIO Configuration
PA5 ------> SPI1_SCK
PA6 ------> SPI1_MISO
PB5 ------> SPI1_MOSI
*/
GPIO_InitStruct.Pin = GPIO_PIN_5|GPIO_PIN_6;
GPIO_InitStruct.Mode = GPIO_MODE_AF_PP;
GPIO_InitStruct.Pull = GPIO_NOPULL;
GPIO_InitStruct.Speed = GPIO_SPEED_FREQ_VERY_HIGH;
GPIO_InitStruct.Alternate = GPIO_AF5_SPI1;
HAL_GPIO_Init(GPIOA, &GPIO_InitStruct);
GPIO_InitStruct.Pin = GPIO_PIN_5;
GPIO_InitStruct.Mode = GPIO_MODE_AF_PP;
GPIO_InitStruct.Pull = GPIO_NOPULL;
GPIO_InitStruct.Speed = GPIO_SPEED_FREQ_VERY_HIGH;
GPIO_InitStruct.Alternate = GPIO_AF5_SPI1;
HAL_GPIO_Init(GPIOB, &GPIO_InitStruct);
/* SPI1 DMA Init */
/* SPI1_RX Init */
hdma_spi1_rx.Instance = DMA2_Stream0;
hdma_spi1_rx.Init.Channel = DMA_CHANNEL_3;
hdma_spi1_rx.Init.Direction = DMA_PERIPH_TO_MEMORY;
hdma_spi1_rx.Init.PeriphInc = DMA_PINC_DISABLE;
hdma_spi1_rx.Init.MemInc = DMA_MINC_ENABLE;
hdma_spi1_rx.Init.PeriphDataAlignment = DMA_PDATAALIGN_BYTE;
hdma_spi1_rx.Init.MemDataAlignment = DMA_MDATAALIGN_BYTE;
hdma_spi1_rx.Init.Mode = DMA_NORMAL;
hdma_spi1_rx.Init.Priority = DMA_PRIORITY_LOW;
hdma_spi1_rx.Init.FIFOMode = DMA_FIFOMODE_DISABLE;
if (HAL_DMA_Init(&hdma_spi1_rx) != HAL_OK)
{
}
__HAL_LINKDMA(hspi,hdmarx,hdma_spi1_rx);
/* SPI1_TX Init */
hdma_spi1_tx.Instance = DMA2_Stream3;
hdma_spi1_tx.Init.Channel = DMA_CHANNEL_3;
hdma_spi1_tx.Init.Direction = DMA_MEMORY_TO_PERIPH;
hdma_spi1_tx.Init.PeriphInc = DMA_PINC_DISABLE;
hdma_spi1_tx.Init.MemInc = DMA_MINC_ENABLE;
hdma_spi1_tx.Init.PeriphDataAlignment = DMA_PDATAALIGN_BYTE;
hdma_spi1_tx.Init.MemDataAlignment = DMA_MDATAALIGN_BYTE;
hdma_spi1_tx.Init.Mode = DMA_NORMAL;
hdma_spi1_tx.Init.Priority = DMA_PRIORITY_LOW;
hdma_spi1_tx.Init.FIFOMode = DMA_FIFOMODE_DISABLE;
if (HAL_DMA_Init(&hdma_spi1_tx) != HAL_OK)
{
}
__HAL_LINKDMA(hspi,hdmatx,hdma_spi1_tx);
/* SPI1 interrupt Init */
HAL_NVIC_SetPriority(SPI1_IRQn, 0, 0);
HAL_NVIC_EnableIRQ(SPI1_IRQn);
/* USER CODE BEGIN SPI1_MspInit 1 */
/* USER CODE END SPI1_MspInit 1 */
/* USER CODE BEGIN SPI1_MspInit 1 */
/* USER CODE END SPI1_MspInit 1 */
}
}
void HAL_SPI_MspDeInit(SPI_HandleTypeDef* hspi)
{
if(hspi->Instance==SPI1)
{
/* USER CODE BEGIN SPI1_MspDeInit 0 */
/* USER CODE END SPI1_MspDeInit 0 */
/* Peripheral clock disable */
__HAL_RCC_SPI1_CLK_DISABLE();
/**SPI1 GPIO Configuration
PA5 ------> SPI1_SCK
PA6 ------> SPI1_MISO
PB5 ------> SPI1_MOSI
*/
HAL_GPIO_DeInit(GPIOA, GPIO_PIN_5|GPIO_PIN_6);
HAL_GPIO_DeInit(GPIOB, GPIO_PIN_5);
/* USER CODE BEGIN SPI1_MspDeInit 1 */
/* Peripheral DMA DeInit*/
HAL_DMA_DeInit(hspi->hdmarx);
HAL_DMA_DeInit(hspi->hdmatx);
/* Peripheral interrupt Deinit*/
HAL_NVIC_DisableIRQ(SPI2_IRQn);
/* USER CODE END SPI1_MspDeInit 1 */
}
}
/* External Interrupt for data ready output of ADC */
void EXTI15_10_IRQHandler(void)
{
/* USER CODE BEGIN EXTI15_10_IRQn 0 */
/* USER CODE END EXTI15_10_IRQn 0 */
HAL_GPIO_EXTI_IRQHandler(GPIO_PIN_15);
/* USER CODE BEGIN EXTI15_10_IRQn 1 */
adc_selectADC(); /* Make Chip Select pin low */
HAL_SPI_Transmit_DMA (&hspi1, &controlByte, 1);
}
void HAL_SPI_TxCpltCallback(SPI_HandleTypeDef *hspi)
{
if (hspi->Instance == hspi1.Instance)
{
/* Transmit is completed */
/* Trigger receive DMA to get raw data from external ADC */
HAL_SPI_Receive_DMA (&hspi1, (uint8_t*)adcRecBuffer, 24);
}
}
void HAL_SPI_RxCpltCallback(SPI_HandleTypeDef *hspi)
{
if (hspi->Instance == hspi1.Instance)
{
/* Receive is completed */
adc_deselectADC(); /* Make Chip Select pin high */
}
}
***Working Algorithm without using DMA or Interrupt:***
/* External Interrupt for data ready output of ADC */
void EXTI15_10_IRQHandler(void)
{
/* USER CODE BEGIN EXTI15_10_IRQn 0 */
/* USER CODE END EXTI15_10_IRQn 0 */
HAL_GPIO_EXTI_IRQHandler(GPIO_PIN_15);
/* USER CODE BEGIN EXTI15_10_IRQn 1 */
adc_selectADC(); /* Make Chip Select pin low */
while(HAL_SPI_GetState(&hspi1) != HAL_SPI_STATE_READY);
HAL_SPI_Transmit(&hspi1, &controlByte, 1,1);
while(HAL_SPI_GetState(&hspi1) != HAL_SPI_STATE_READY);
while(HAL_SPI_GetState(&hspi1) != HAL_SPI_STATE_READY);
HAL_SPI_Receive(&hspi1, (uint8_t*)adcRecBuffer, 24, 1);
while(HAL_SPI_GetState(&hspi1) != HAL_SPI_STATE_READY);
adc_deselectADC(); /* Make Chip Select pin high*/
}