Stm32f407 Uart Dma Multiple Array Tx - stm32

Question

I tried to send Buffer from stm32f407 to terminal.Type is uint8_t and array is 15000. My code is works. but when i try to send 2 buffer like 5000 array, there is problem for second buffer. I use normal mode.What i should do to sending succesfully?
/* USART3 DMA Init */
/* USART3_TX Init */
hdma_usart3_tx.Instance = DMA1_Stream3;
hdma_usart3_tx.Init.Channel = DMA_CHANNEL_4;
hdma_usart3_tx.Init.Direction = DMA_MEMORY_TO_PERIPH;
hdma_usart3_tx.Init.PeriphInc = DMA_PINC_DISABLE;
hdma_usart3_tx.Init.MemInc = DMA_MINC_ENABLE;
hdma_usart3_tx.Init.PeriphDataAlignment = DMA_PDATAALIGN_BYTE;
hdma_usart3_tx.Init.MemDataAlignment = DMA_MDATAALIGN_BYTE;
hdma_usart3_tx.Init.Mode = DMA_NORMAL;
hdma_usart3_tx.Init.Priority = DMA_PRIORITY_VERY_HIGH;
hdma_usart3_tx.Init.FIFOMode = DMA_FIFOMODE_DISABLE;
if (HAL_DMA_Init(&hdma_usart3_tx) != HAL_OK)
{
Error_Handler();
}
__HAL_LINKDMA(huart,hdmatx,hdma_usart3_tx);
/* USART3 interrupt Init */
HAL_NVIC_SetPriority(USART3_IRQn, 0, 0);
HAL_NVIC_EnableIRQ(USART3_IRQn);
/* USER CODE BEGIN USART3_MspInit 1 */
/* USER CODE END USART3_MspInit 1 */
void Send_Dataa(void)
{
HAL_UART_Transmit_DMA(wifi_uart, buf1, 5000);
HAL_UART_Transmit_DMA(wifi_uart, buf2, 5000);
}

Answer 1

If you check the return code from HAL_UART_Transmit_DMA(), you'll probably see it is returning HAL_BUSY. (Note you should always be checking the return codes from HAL functions.)
You'll need to wait until the first transmit is complete before starting the second transmit. You can use HAL_UART_GetState() to monitor the state of the UART.
The HAL does not chain together multiple DMA requests.