RT-Thread-STM32L4 LPUART1 DMA下不能工作的解决办法RT-Thread问答社区

STM32L4 LPUART1 DMA下不能工作的解决办法

发布于 2022-02-25 22:55:43 浏览：1349 订阅该版

最近项目上使用了STM32L4系列的单片机，需要使用多个串口实现与外部的通信，故发现使用LPUART1 在DMA下不能正常工作这一情况。
    
在论坛搜索发现也有不少人遇到该问题我打算把自己解决的办法提供给大家试一试。
    
rtt版本4.0.5，单片机STM32L431，STM32Cube V1.17.1
MDK-ARM V5.36,使用AC6 V6.16
    
（以上都不重要）

问题出在drv_usart.c文件中stm32_uart_get_dma_config()缺少LPUART1 DMA 配置：
```
static void stm32_uart_get_dma_config(void)
{
#ifdef BSP_USING_UART1
    uart_obj[UART1_INDEX].uart_dma_flag = 0;
#ifdef BSP_UART1_RX_USING_DMA
    uart_obj[UART1_INDEX].uart_dma_flag |= RT_DEVICE_FLAG_DMA_RX;
    static struct dma_config uart1_dma_rx = UART1_DMA_RX_CONFIG;
    uart_config[UART1_INDEX].dma_rx = &uart1_dma_rx;
#endif
#ifdef BSP_UART1_TX_USING_DMA
    uart_obj[UART1_INDEX].uart_dma_flag |= RT_DEVICE_FLAG_DMA_TX;
    static struct dma_config uart1_dma_tx = UART1_DMA_TX_CONFIG;
    uart_config[UART1_INDEX].dma_tx = &uart1_dma_tx;
#endif
#endif

#ifdef BSP_USING_UART2
    uart_obj[UART2_INDEX].uart_dma_flag = 0;
#ifdef BSP_UART2_RX_USING_DMA
    uart_obj[UART2_INDEX].uart_dma_flag |= RT_DEVICE_FLAG_DMA_RX;
    static struct dma_config uart2_dma_rx = UART2_DMA_RX_CONFIG;
    uart_config[UART2_INDEX].dma_rx = &uart2_dma_rx;
#endif
#ifdef BSP_UART2_TX_USING_DMA
    uart_obj[UART2_INDEX].uart_dma_flag |= RT_DEVICE_FLAG_DMA_TX;
    static struct dma_config uart2_dma_tx = UART2_DMA_TX_CONFIG;
    uart_config[UART2_INDEX].dma_tx = &uart2_dma_tx;
#endif
#endif

#ifdef BSP_USING_UART3
    uart_obj[UART3_INDEX].uart_dma_flag = 0;
#ifdef BSP_UART3_RX_USING_DMA
    uart_obj[UART3_INDEX].uart_dma_flag |= RT_DEVICE_FLAG_DMA_RX;
    static struct dma_config uart3_dma_rx = UART3_DMA_RX_CONFIG;
    uart_config[UART3_INDEX].dma_rx = &uart3_dma_rx;
#endif
#ifdef BSP_UART3_TX_USING_DMA
    uart_obj[UART3_INDEX].uart_dma_flag |= RT_DEVICE_FLAG_DMA_TX;
    static struct dma_config uart3_dma_tx = UART3_DMA_TX_CONFIG;
    uart_config[UART3_INDEX].dma_tx = &uart3_dma_tx;
#endif
#endif

#ifdef BSP_USING_UART4
    uart_obj[UART4_INDEX].uart_dma_flag = 0;
#ifdef BSP_UART4_RX_USING_DMA
    uart_obj[UART4_INDEX].uart_dma_flag |= RT_DEVICE_FLAG_DMA_RX;
    static struct dma_config uart4_dma_rx = UART4_DMA_RX_CONFIG;
    uart_config[UART4_INDEX].dma_rx = &uart4_dma_rx;
#endif
#ifdef BSP_UART4_TX_USING_DMA
    uart_obj[UART4_INDEX].uart_dma_flag |= RT_DEVICE_FLAG_DMA_TX;
    static struct dma_config uart4_dma_tx = UART4_DMA_TX_CONFIG;
    uart_config[UART4_INDEX].dma_tx = &uart4_dma_tx;
#endif
#endif

#ifdef BSP_USING_UART5
    uart_obj[UART5_INDEX].uart_dma_flag = 0;
#ifdef BSP_UART5_RX_USING_DMA
    uart_obj[UART5_INDEX].uart_dma_flag |= RT_DEVICE_FLAG_DMA_RX;
    static struct dma_config uart5_dma_rx = UART5_DMA_RX_CONFIG;
    uart_config[UART5_INDEX].dma_rx = &uart5_dma_rx;
#endif
#ifdef BSP_UART5_TX_USING_DMA
    uart_obj[UART5_INDEX].uart_dma_flag |= RT_DEVICE_FLAG_DMA_TX;
    static struct dma_config uart5_dma_tx = UART5_DMA_TX_CONFIG;
    uart_config[UART5_INDEX].dma_tx = &uart5_dma_tx;
#endif
#endif

#ifdef BSP_USING_UART6
    uart_obj[UART6_INDEX].uart_dma_flag = 0;
#ifdef BSP_UART6_RX_USING_DMA
    uart_obj[UART6_INDEX].uart_dma_flag |= RT_DEVICE_FLAG_DMA_RX;
    static struct dma_config uart6_dma_rx = UART6_DMA_RX_CONFIG;
    uart_config[UART6_INDEX].dma_rx = &uart6_dma_rx;
#endif
#ifdef BSP_UART6_TX_USING_DMA
    uart_obj[UART6_INDEX].uart_dma_flag |= RT_DEVICE_FLAG_DMA_TX;
    static struct dma_config uart6_dma_tx = UART6_DMA_TX_CONFIG;
    uart_config[UART6_INDEX].dma_tx = &uart6_dma_tx;
#endif
#endif
}
```

修改后增加LPUART1 DMA配置：

```
static void stm32_uart_get_dma_config(void)
{
#ifdef BSP_USING_LPUART1
    uart_obj[LPUART1_INDEX].uart_dma_flag = 0;
#ifdef BSP_LPUART1_RX_USING_DMA
    uart_obj[LPUART1_INDEX].uart_dma_flag |= RT_DEVICE_FLAG_DMA_RX;
    static struct dma_config LPUART1_dma_rx = LPUART1_DMA_CONFIG;
    uart_config[LPUART1_INDEX].dma_rx = &LPUART1_dma_rx;
#endif
#ifdef BSP_LPUART1_TX_USING_DMA
    uart_obj[LPUART1_INDEX].uart_dma_flag |= RT_DEVICE_FLAG_DMA_TX;
    static struct dma_config LPUART1_dma_tx = LPUART1_DMA_CONFIG;
    uart_config[LPUART1_INDEX].dma_tx = &LPUART1_dma_tx;
#endif
#endif

#ifdef BSP_USING_UART1
    uart_obj[UART1_INDEX].uart_dma_flag = 0;
#ifdef BSP_UART1_RX_USING_DMA
    uart_obj[UART1_INDEX].uart_dma_flag |= RT_DEVICE_FLAG_DMA_RX;
    static struct dma_config uart1_dma_rx = UART1_DMA_RX_CONFIG;
    uart_config[UART1_INDEX].dma_rx = &uart1_dma_rx;
#endif
#ifdef BSP_UART1_TX_USING_DMA
    uart_obj[UART1_INDEX].uart_dma_flag |= RT_DEVICE_FLAG_DMA_TX;
    static struct dma_config uart1_dma_tx = UART1_DMA_TX_CONFIG;
    uart_config[UART1_INDEX].dma_tx = &uart1_dma_tx;
#endif
#endif

测试的时候发现有DMA分包的问题。论坛里已有解决办法。
需要在drv_usart.c文件中找到HAL_UART_RxCpltCallback()
HAL_UART_RxHalfCpltCallback()这两个函数里面把dma_isr(&uart->serial)屏蔽掉。
```
void HAL_UART_RxCpltCallback(UART_HandleTypeDef *huart)
{
    struct stm32_uart *uart;
    RT_ASSERT(huart != NULL);
    uart = (struct stm32_uart *)huart;
//    dma_isr(&uart->serial);
}
```
```
void HAL_UART_RxHalfCpltCallback(UART_HandleTypeDef *huart)
{
    struct stm32_uart *uart;
    RT_ASSERT(huart != NULL);
    uart = (struct stm32_uart *)huart;
//    dma_isr(&uart->serial);
}
```

因为DMA的传输完成和半传输完成中断造成的分包。屏蔽后就是串口空闲中断起作用。