源碼連結:STM32H7序列槽DMA空閑中斷收發不定長資料_Code
視訊連結:STM32H7序列槽DMA空閑中斷收發不定長資料
序列槽中斷:序列槽中斷使用的比較多,收到一個位元組的資料就進入一次中斷,這樣每一個位元組都需要進入中斷,這樣就大大增加了CPU的負荷。
序列槽DMA:在使用序列槽DMA時候,會大大降低CPU的負荷,資料的傳輸會直接通過DMA傳輸,不需要CPU的幹預,但是在接收資料的時候,接收的資料是固定長度的,如果需要接收不定長資料的話就需要添加很多軟體代碼來判斷資料是否接收完成,比較複雜。
序列槽DAM+空閑中斷:在序列槽使用DMA時候同時使用空閑中斷,這樣就可以接收不定長資料,并且還可以記錄接收到的資料長度,這樣不僅可以減小CPU的負荷,還可以簡化代碼的複雜程度
部分核心代碼如下:
void MX_USART1_UART_Init(void)
{
huart1.Instance = USART1;
huart1.Init.BaudRate = 115200;
huart1.Init.WordLength = UART_WORDLENGTH_8B;
huart1.Init.StopBits = UART_STOPBITS_1;
huart1.Init.Parity = UART_PARITY_NONE;
huart1.Init.Mode = UART_MODE_TX_RX;
huart1.Init.HwFlowCtl = UART_HWCONTROL_NONE;
huart1.Init.OverSampling = UART_OVERSAMPLING_16;
huart1.Init.OneBitSampling = UART_ONE_BIT_SAMPLE_DISABLE;
huart1.Init.ClockPrescaler = UART_PRESCALER_DIV1;
huart1.AdvancedInit.AdvFeatureInit = UART_ADVFEATURE_NO_INIT;
if (HAL_UART_Init(&huart1) != HAL_OK)
{
Error_Handler();
}
if (HAL_UARTEx_SetTxFifoThreshold(&huart1, UART_TXFIFO_THRESHOLD_1_8) != HAL_OK)
{
Error_Handler();
}
if (HAL_UARTEx_SetRxFifoThreshold(&huart1, UART_RXFIFO_THRESHOLD_1_8) != HAL_OK)
{
Error_Handler();
}
if (HAL_UARTEx_DisableFifoMode(&huart1) != HAL_OK)
{
Error_Handler();
}
__HAL_UART_ENABLE_IT(&huart1,UART_IT_IDLE);
HAL_UART_Receive_DMA(&huart1, RxBuffer, RxBufferSize);
}
void HAL_UART_MspInit(UART_HandleTypeDef* uartHandle)
{
GPIO_InitTypeDef GPIO_InitStruct = {0};
RCC_PeriphCLKInitTypeDef PeriphClkInitStruct = {0};
if(uartHandle->Instance==USART1)
{
PeriphClkInitStruct.PeriphClockSelection = RCC_PERIPHCLK_USART1;
PeriphClkInitStruct.Usart16ClockSelection = RCC_USART16CLKSOURCE_D2PCLK2;
if (HAL_RCCEx_PeriphCLKConfig(&PeriphClkInitStruct) != HAL_OK)
{
Error_Handler();
}
__HAL_RCC_USART1_CLK_ENABLE();
__HAL_RCC_GPIOA_CLK_ENABLE();
/**USART1 GPIO Configuration
PA10 ------> USART1_RX
PA9 ------> USART1_TX
*/
GPIO_InitStruct.Pin = GPIO_PIN_10|GPIO_PIN_9;
GPIO_InitStruct.Mode = GPIO_MODE_AF_PP;
GPIO_InitStruct.Pull = GPIO_PULLUP;
GPIO_InitStruct.Speed = GPIO_SPEED_FREQ_LOW;
GPIO_InitStruct.Alternate = GPIO_AF7_USART1;
HAL_GPIO_Init(GPIOA, &GPIO_InitStruct);
/* USART1 DMA Init */
/* USART1_RX Init */
hdma_usart1_rx.Instance = DMA1_Stream0;
hdma_usart1_rx.Init.Request = DMA_REQUEST_USART1_RX;
hdma_usart1_rx.Init.Direction = DMA_PERIPH_TO_MEMORY;
hdma_usart1_rx.Init.PeriphInc = DMA_PINC_DISABLE;
hdma_usart1_rx.Init.MemInc = DMA_MINC_ENABLE;
hdma_usart1_rx.Init.PeriphDataAlignment = DMA_PDATAALIGN_BYTE;
hdma_usart1_rx.Init.MemDataAlignment = DMA_MDATAALIGN_BYTE;
hdma_usart1_rx.Init.Mode = DMA_CIRCULAR;
hdma_usart1_rx.Init.Priority = DMA_PRIORITY_LOW;
hdma_usart1_rx.Init.FIFOMode = DMA_FIFOMODE_DISABLE;
if (HAL_DMA_Init(&hdma_usart1_rx) != HAL_OK)
{
Error_Handler();
}
__HAL_LINKDMA(uartHandle,hdmarx,hdma_usart1_rx);
/* USART1_TX Init */
hdma_usart1_tx.Instance = DMA1_Stream1;
hdma_usart1_tx.Init.Request = DMA_REQUEST_USART1_TX;
hdma_usart1_tx.Init.Direction = DMA_MEMORY_TO_PERIPH;
hdma_usart1_tx.Init.PeriphInc = DMA_PINC_DISABLE;
hdma_usart1_tx.Init.MemInc = DMA_MINC_ENABLE;
hdma_usart1_tx.Init.PeriphDataAlignment = DMA_PDATAALIGN_BYTE;
hdma_usart1_tx.Init.MemDataAlignment = DMA_MDATAALIGN_BYTE;
hdma_usart1_tx.Init.Mode = DMA_NORMAL;
hdma_usart1_tx.Init.Priority = DMA_PRIORITY_LOW;
hdma_usart1_tx.Init.FIFOMode = DMA_FIFOMODE_DISABLE;
if (HAL_DMA_Init(&hdma_usart1_tx) != HAL_OK)
{
Error_Handler();
}
__HAL_LINKDMA(uartHandle,hdmatx,hdma_usart1_tx);
HAL_NVIC_SetPriority(USART1_IRQn, 1, 0);
HAL_NVIC_EnableIRQ(USART1_IRQn);
}
}
void HAL_UART_TxCpltCallback(UART_HandleTypeDef *huart)
{
if(huart->Instance == USART1)
{
HAL_UART_Receive_DMA(&huart1, RxBuffer, RxBufferSize);
RxNum = 0;
memset(RxBuffer,0,RxBufferSize);
}
}
void USART1_IRQHandler(void)
{
if(__HAL_UART_GET_FLAG(&huart1,UART_FLAG_IDLE) == SET)
{
__HAL_UART_CLEAR_IDLEFLAG(&huart1);
HAL_UART_DMAStop(&huart1);
RxNum = RxBufferSize - __HAL_DMA_GET_COUNTER(&hdma_usart1_rx);
HAL_UART_Transmit_DMA(&huart1, RxBuffer, RxNum);
}
HAL_UART_IRQHandler(&huart1);
}