read continuous data through UART

[dixon]

Posted on November 02, 2016 at 10:52

I am a beginner, I have the Uart dma example code. How can i change the program to receive the continuous data obtained from the TX in RX  in a simple way. Here is my main fucntion

&sharpinclude ''main.h''&sharpinclude ''stm32f4xx_hal.h''&sharpinclude ''dma.h''&sharpinclude ''usart.h''&sharpinclude ''gpio.h''/* USER CODE BEGIN Includes */&sharpdefine TXSTARTMESSAGESIZE               (COUNTOF(aTxStartMessage) - 1)&sharpdefine TXENDMESSAGESIZE                 (COUNTOF(aTxEndMessage) - 1)/* Size of Reception buffer */&sharpdefine RXBUFFERSIZE                     10/* Exported macro ------------------------------------------------------------*/&sharpdefine COUNTOF(__BUFFER__)   (sizeof(__BUFFER__) / sizeof(*(__BUFFER__)))/* USER CODE END Includes *//* Private variables ---------------------------------------------------------*//* USER CODE BEGIN PV *//* Private variables ---------------------------------------------------------*//* USER CODE END PV *//** @addtogroup UART_Hyperterminal_DMA  * @{  */ /* Private typedef -----------------------------------------------------------*//* Private define ------------------------------------------------------------*//* Private macro -------------------------------------------------------------*//* Private variables ---------------------------------------------------------*//* UART handler declaration *//* Buffer used for transmission */uint8_t aTxStartMessage[] = ''\n\r ****UART-Hyperterminal communication based on DMA ****\n\r Enter 10 characters using keyboard :\n\r'';uint8_t aTxEndMessage[] = ''\n\r Example Finished\n\r'';/* Buffer used for reception */uint8_t aRxBuffer[RXBUFFERSIZE];/* Private function prototypes -----------------------------------------------*/void SystemClock_Config(void);void Error_Handler(void);/* USER CODE BEGIN PFP *//* Private function prototypes -----------------------------------------------*//* USER CODE END PFP *//* USER CODE BEGIN 0 *//* USER CODE END 0 */int main(void){  /* USER CODE BEGIN 1 */  /* USER CODE END 1 */  /* MCU Configuration----------------------------------------------------------*/  /* Reset of all peripherals, Initializes the Flash interface and the Systick. */  HAL_Init();  /* Configure the system clock */  SystemClock_Config();  /* Initialize all configured peripherals */  MX_GPIO_Init();  MX_DMA_Init();  MX_UART8_Init();HAL_UART_MspInit(&huart8);  /* USER CODE BEGIN 2 */ /*♯♯-2- Start the transmission process ♯♯♯♯♯♯♯♯♯♯♯♯♯♯♯♯♯♯♯♯♯♯♯♯♯♯♯♯♯♯♯♯♯♯♯♯♯*/    /* User start transmission data through ''TxBuffer'' buffer */  if(HAL_UART_Transmit_DMA(&huart8, (uint8_t*)aTxStartMessage, TXSTARTMESSAGESIZE)!= HAL_OK)  {    /* Transfer error in transmission process */    Error_Handler();    }    /*♯♯-3- Put UART peripheral in reception process ♯♯♯♯♯♯♯♯♯♯♯♯♯♯♯♯♯♯♯♯♯♯♯♯♯♯♯*/    /* Any data received will be stored in ''RxBuffer'' buffer : the number max of      data received is 10 */  if(HAL_UART_Receive_DMA(&huart8, (uint8_t *)aRxBuffer, RXBUFFERSIZE) != HAL_OK)  {    /* Transfer error in reception process */    Error_Handler();       }  /*♯♯-4- Wait for the end of the transfer ♯♯♯♯♯♯♯♯♯♯♯♯♯♯♯♯♯♯♯♯♯♯♯♯♯♯♯♯♯♯♯♯♯♯♯*/    /*  Before starting a new communication transfer, you need to check the current          state of the peripheral; if it�s busy you need to wait for the end of current      transfer before starting a new one.      For simplicity reasons, this example is just waiting till the end of the       transfer, but application may perform other tasks while transfer operation      is ongoing. */    while (HAL_UART_GetState(&huart8) != HAL_UART_STATE_READY)  {  }    /*♯♯-5- Send the received Buffer ♯♯♯♯♯♯♯♯♯♯♯♯♯♯♯♯♯♯♯♯♯♯♯♯♯♯♯♯♯♯♯♯♯♯♯♯♯♯♯♯♯♯♯*/    if(HAL_UART_Transmit_DMA(&huart8, (uint8_t*)aRxBuffer, RXBUFFERSIZE)!= HAL_OK)  {    /* Transfer error in transmission process */    Error_Handler();      }    /*♯♯-6- Wait for the end of the transfer ♯♯♯♯♯♯♯♯♯♯♯♯♯♯♯♯♯♯♯♯♯♯♯♯♯♯♯♯♯♯♯♯♯♯♯*/    while (HAL_UART_GetState(&huart8) != HAL_UART_STATE_READY)  {  }   /*♯♯-7- Send the End Message ♯♯♯♯♯♯♯♯♯♯♯♯♯♯♯♯♯♯♯♯♯♯♯♯♯♯♯♯♯♯♯♯♯♯♯♯♯♯♯♯♯♯♯♯♯♯♯*/    if(HAL_UART_Transmit_DMA(&huart8, (uint8_t*)aTxEndMessage, TXENDMESSAGESIZE)!= HAL_OK)  {    /* Turn LED3 on: Transfer error in transmission process */   // BSP_LED_On(LED3);    while(1)    {    }        }    /*♯♯-8- Wait for the end of the transfer ♯♯♯♯♯♯♯♯♯♯♯♯♯♯♯♯♯♯♯♯♯♯♯♯♯♯♯♯♯♯♯♯♯♯♯*/    while (HAL_UART_GetState(&huart8) != HAL_UART_STATE_READY)  {  }  /* Infinite loop */    while (1)  {  }}  /* USER CODE END 2 */  /* Infinite loop */  /* USER CODE BEGIN WHILE */ This is configured for the MCU by taking UART8. Help me its urgent  #no-hablo-hal

[Amel NASRI]

Posted on November 15, 2016 at 11:44

Hi sunny.dixon_p,

What are you trying to do exactly?What is going wrong with the code you provided?-Mayla-

[AvaTar]

Posted on November 15, 2016 at 14:58

Why are yo polling, and not using interrupts ?

They are designed as immediate responses to external events. > Help me its urgent Do you honestly expect someone else to take the heat for you ????

[Tesla DeLorean]

Posted on November 15, 2016 at 16:02

What is going wrong with the code you provided?

The OP expressed the desire for it to support reception of data also.

http://www.catb.org/~esr/faqs/smart-questions.html#urgent

[Alan Chambers]

Posted on November 15, 2016 at 17:04

My USART DMA driver does the following:

For TX: - Maintains a queue of pending DMA transfers (of variable length). - I cache the actual data in a TX ring buffer (a little care is need when this wraps - split into - two transfers). - On TC interrupt fetch the next transfer off the queue, set MOAR and NDTR, and re-enable the stream. For RX: - I use a circular buffer for the DMA. - Don't interrupt (I might wait forever for enough data to cause the interrupt). - Poll frequently (SysTick at 1kHz) and test NDTR to see if any new data has been received. - Copy new data into an RX ring buffer (watch the wrapping). - Emit an event to my scheduler to indicate to whoever cares that there is new data to be consumed.   No doubt there are better solutions. But it seems pretty robust. I use a scheduler to decouple subsystems, but a synchronous callback would do just as well as an asynchronous event.