直接调用不就好了, 只要有数据就可以读取到, 或者调用 tls_uart_try_read

case DEMO_MSG_UART_RECEIVE_DATA:

    {
        rx_len = uart- rx_data_len; 
        while  (rx_len   0) 
        {
            printf ("\n----1  rx_len----%d",  rx_len) ; 
            len =  (rx_len   DEMO_UART_RX_BUF_SIZE)  ?  DEMO_UART_RX_BUF_SIZE :  rx_len; 
            printf ("\n----2  len----%d",  len) ; 
            memset (uart- rx_buf,  0,   (DEMO_UART_RX_BUF_SIZE + 1) ) ; 
            tls_uart_read (TLS_UART_1,  msg_rxfifo_buf,  len) ; 
            tls_uart_read (TLS_UART_1,  rx_fifo_buf1[0],  len) ; 
            printf ("\n----####  msg_rxfifo_buf----%s\n",  msg_rxfifo_buf) ; 
            printf ("\n----####  rx_fifo_buf1[0]----%s\n",  rx_fifo_buf1[0]) ; 
            ret = tls_uart_read (TLS_UART_1,   (u8 *) uart- rx_buf,  len) ; 
            ret = tls_uart_read (TLS_UART_1,   (u8 *) uart- rx_buf,  len) ;  /* input */
            printf ("\n----####  DEMO_MSG_UART_RECEIVE_DATA----%s\n",  uart- rx_buf) ; 
            printf ("\n----3  ret----%d",  ret) ; 

            if  (ret  = 0) 
            {
                break; 
            }

            rx_len -= ret; 
            uart- rx_data_len -= ret; 

if USE_DMA_TX_FTR

            // tls_uart_dma_write (uart- rx_buf,  len,  uart_dma_done,  TLS_UART_1) ; 

else

            tls_uart_write (TLS_UART_1,  uart- rx_buf,  len) ;  /* output */
            printf ("\n----4  DEMO_MSG_UART_RECEIVE_DATA  uart- rx_buf----%s\n",  uart- rx_buf) ; 

endif

        }
        printf ("\n----5  DEMO_MSG_UART_RECEIVE_DATA  uart- rx_msg_num----%s\n",  uart- rx_msg_num) ; 
        if  (uart- rx_msg_num   0) 
        {
            uart- rx_msg_num--; 
        }

        printf ("\n----6  DEMO_MSG_UART_RECEIVE_DATA----%s\n",  uart- rx_buf) ; 
    }
    break; 
    
    代码用的是开发板自带的 wm_uart_demo. c
    我修改了下,  运行得不到发送过来的 1234