songshiqun2010 发表于 2016-6-23 09:47:12

如何使用HAL库，实现不定长UART数据包的DMA接收

本帖最后由 songshiqun2010 于 2019-6-13 13:28 编辑

uint8_t txbuf="helloworld\r\n";
uint8_t rxbuf="";
ART_HandleTypeDef huart1;


HAL_UART_Receive_DMA(&huart1,rxbuf,sizeof(rxbuf))；

函数原型如下：
/**
* @briefReceives an amount of data in non blocking mode.
* @paramhuart: pointer to a UART_HandleTypeDef structure that contains
*                the configuration information for the specified UART module.
* @parampData: Pointer to data buffer
* @paramSize: Amount of data to be received
* @note   When the UART parity is enabled (PCE = 1) the data received contain the parity bit.
* @retval HAL status
*/
HAL_StatusTypeDef HAL_UART_Receive_DMA(UART_HandleTypeDef *huart, uint8_t *pData, uint16_t Size)
{
uint32_t *tmp;
uint32_t tmp1 = 0;

tmp1 = huart->State;   
if((tmp1 == HAL_UART_STATE_READY) || (tmp1 == HAL_UART_STATE_BUSY_TX))
{
    if((pData == NULL ) || (Size == 0))
    {
      return HAL_ERROR;
    }

    /* Process Locked */
    __HAL_LOCK(huart);

    huart->pRxBuffPtr = pData;
    huart->RxXferSize = Size;

    huart->ErrorCode = HAL_UART_ERROR_NONE;
    /* Check if a transmit process is ongoing or not */
    if(huart->State == HAL_UART_STATE_BUSY_TX)
    {
      huart->State = HAL_UART_STATE_BUSY_TX_RX;
    }
    else
    {
      huart->State = HAL_UART_STATE_BUSY_RX;
    }

    /* Set the UART DMA transfer complete callback */
    huart->hdmarx->XferCpltCallback = UART_DMAReceiveCplt;

    /* Set the UART DMA Half transfer complete callback */
    huart->hdmarx->XferHalfCpltCallback = UART_DMARxHalfCplt;

    /* Set the DMA error callback */
    huart->hdmarx->XferErrorCallback = UART_DMAError;

    /* Enable the DMA Stream */
    tmp = (uint32_t*)&pData;
    HAL_DMA_Start_IT(huart->hdmarx, (uint32_t)&huart->Instance->DR, *(uint32_t*)tmp, Size);

    /* Enable the DMA transfer for the receiver request by setting the DMAR bit
    in the UART CR3 register */
    huart->Instance->CR3 |= USART_CR3_DMAR;

    /* Process Unlocked */
    __HAL_UNLOCK(huart);

    return HAL_OK;
}
else
{
    return HAL_BUSY;
}
}

传送门 HAL UART DMA 环形缓冲接收不定长数据包


大林林 发表于 2016-6-23 12:40:07

如果串口接收频率不高，不是可以使用串口自带的空中断，如果连续接收的，那就DMA收定长的数据，然后做好协议，拼接。
楼下有高见吗

ataudio 发表于 2017-7-11 16:29:48

楼上说的对。如果不是ADC之类的自动转换后的连续收发，没必要用DMA中断的UART，用自带的中断就足够了。

用缓存存储数据，整合后发送或者处理。

一叶清风 发表于 2018-1-5 22:57:48

谢谢分享
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