STM32,HAL库uart+dma空闲中断，波特率9600及以下通讯没问题，到19200就不行了。

HAL库uart+dma空闲中断，波特率9600及以下通讯没问题，到19200就不行了。IDLE中断中 __HAL_DMA_GET_COUNTER(huart->hdmarx)的值一直是255，BUF中只有第一位是有效的，后面的都是0。搞不清楚是什么原因。

void MX_USART2_UART_Init( )
{
huart2.Instance = USART2;
huart2.Init.BaudRate = 19200;

huart2.Init.StopBits = UART_STOPBITS_1;
huart2.Init.Parity = UART_PARITY_NONE ;
huart2.Init.WordLength = UART_WORDLENGTH_8B;
huart2.Init.Mode = UART_MODE_TX_RX;
huart2.Init.HwFlowCtl = UART_HWCONTROL_NONE;
huart2.Init.OverSampling = UART_OVERSAMPLING_16;
huart2.Init.OneBitSampling = UART_ONE_BIT_SAMPLE_DISABLE;
huart2.Init.ClockPrescaler = UART_PRESCALER_DIV1;
huart2.AdvancedInit.AdvFeatureInit = UART_ADVFEATURE_RXOVERRUNDISABLE_INIT|UART_ADVFEATURE_DMADISABLEONERROR_INIT;
huart2.AdvancedInit.OverrunDisable = UART_ADVFEATURE_OVERRUN_DISABLE;
huart2.AdvancedInit.DMADisableonRxError = UART_ADVFEATURE_DMA_DISABLEONRXERROR;
if (HAL_UART_Init(&huart2) != HAL_OK)
{
Error_Handler();
}
if (HAL_UARTEx_SetTxFifoThreshold(&huart2, UART_TXFIFO_THRESHOLD_1_8) != HAL_OK)
{
Error_Handler();
}
if (HAL_UARTEx_SetRxFifoThreshold(&huart2, UART_RXFIFO_THRESHOLD_1_8) != HAL_OK)
{
Error_Handler();
}
if (HAL_UARTEx_DisableFifoMode(&huart2) != HAL_OK)
{
Error_Handler();
}

}

void HAL_UART_MspInit(UART_HandleTypeDef* uartHandle)
{

GPIO_InitTypeDef GPIO_InitStruct = {0};
if(uartHandle->Instance==USART2)
{
/* USER CODE BEGIN USART2_MspInit 0 */

/* USER CODE END USART2_MspInit 0 /
/ USART2 clock enable */
__HAL_RCC_USART2_CLK_ENABLE();

__HAL_RCC_GPIOD_CLK_ENABLE();
/**USART2 GPIO Configuration    
PD5     ------> USART2_TX
PD6     ------> USART2_RX 
*/
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_HIGH;
GPIO_InitStruct.Alternate = GPIO_AF0_USART2;
HAL_GPIO_Init(GPIOD, &GPIO_InitStruct);

/* USART2 DMA Init */
/* USART2_RX Init */
hdma_usart2_rx.Instance = DMA1_Channel2;
hdma_usart2_rx.Init.Request = DMA_REQUEST_USART2_RX;
hdma_usart2_rx.Init.Direction = DMA_PERIPH_TO_MEMORY;
hdma_usart2_rx.Init.PeriphInc = DMA_PINC_DISABLE;
hdma_usart2_rx.Init.MemInc = DMA_MINC_ENABLE;
hdma_usart2_rx.Init.PeriphDataAlignment = DMA_PDATAALIGN_BYTE;
hdma_usart2_rx.Init.MemDataAlignment = DMA_MDATAALIGN_BYTE;
hdma_usart2_rx.Init.Mode = DMA_NORMAL;
hdma_usart2_rx.Init.Priority = DMA_PRIORITY_HIGH;
if (HAL_DMA_Init(&hdma_usart2_rx) != HAL_OK)
{
  Error_Handler();
}

__HAL_LINKDMA(uartHandle,hdmarx,hdma_usart2_rx);

/* USART2_TX Init */
hdma_usart2_tx.Instance = DMA1_Channel3;
hdma_usart2_tx.Init.Request = DMA_REQUEST_USART2_TX;
hdma_usart2_tx.Init.Direction = DMA_MEMORY_TO_PERIPH;
hdma_usart2_tx.Init.PeriphInc = DMA_PINC_DISABLE;
hdma_usart2_tx.Init.MemInc = DMA_MINC_ENABLE;
hdma_usart2_tx.Init.PeriphDataAlignment = DMA_PDATAALIGN_BYTE;
hdma_usart2_tx.Init.MemDataAlignment = DMA_MDATAALIGN_BYTE;
hdma_usart2_tx.Init.Mode = DMA_NORMAL;
hdma_usart2_tx.Init.Priority = DMA_PRIORITY_HIGH;
if (HAL_DMA_Init(&hdma_usart2_tx) != HAL_OK)
{
  Error_Handler();
}

__HAL_LINKDMA(uartHandle,hdmatx,hdma_usart2_tx);

/* USART2 interrupt Init */
HAL_NVIC_SetPriority(USART2_IRQn, 0, 0);
HAL_NVIC_EnableIRQ(USART2_IRQn);

/* USER CODE BEGIN USART2_MspInit 1 */

/* USER CODE END USART2_MspInit 1 */
}
}

可以尝试修改一下中断优先级，还有系统时钟优先级，中断分组等参数。