HAL_UART_Transmit_DMA problem

[Min-Kyoung Kim]

Posted on February 06, 2017 at 14:22

I had problem for 'HAL_UART_Transmit_DMA', once I transmitted some data, I couldn't send any data after that.

I used this function,

'HAL_UART_Transmit_DMA' in 'USART1_IRQHander'.

(Because I should parse the data as soon as I receive any data. (N of data is not fixed.).)

So I found the solution in this forum. And I succeeded using'HAL_UART_Transmit_DMA'.

I attached one line(huart->gState = HAL_UART_STATE_READY;) in 'UART_DMATransmitCplt' like below.

static void UART_DMATransmitCplt(DMA_HandleTypeDef *hdma)
{
 UART_HandleTypeDef* huart = ( UART_HandleTypeDef* )((DMA_HandleTypeDef* )hdma)->Parent;
 /* DMA Normal mode*/
 if((hdma->Instance->CR & DMA_SxCR_CIRC) == 0U)
 {
 huart->TxXferCount = 0U;
/* Disable the DMA transfer for transmit request by setting the DMAT bit
 in the UART CR3 register */
 CLEAR_BIT(huart->Instance->CR3, USART_CR3_DMAT);
/* Enable the UART Transmit Complete Interrupt */
 SET_BIT(huart->Instance->CR1, USART_CR1_TCIE);
huart->gState = HAL_UART_STATE_READY; <- this!!!!
}�?�?�?�?�?�?�?�?�?�?�?�?�?�?

But I wonder if I can use

'HAL_UART_Transmit_DMA' in'USART1_IRQHander'.

Does any problem happen later?

Please answer me,

#usart1 #dam

[T J]

Posted on February 06, 2017 at 21:58

Try this one...

void CheckTxDMABufferProgress(void){ if ( DMABufHasData ){ char uartState = HAL_UART_GetState(&huart1); if ((uartState == HAL_UART_STATE_READY) || (uartState == HAL_UART_STATE_BUSY_RX)) { DMABufHasData = false; // sending now if (HAL_UART_Transmit_DMA(&huart1, (uint8_t *)Usart1TxDMABuffer + U1TxBufferPtrOUT ,U1TxBufferPtrIN - U1TxBufferPtrOUT) == HAL_OK){ HAL_UART_Transmit_DMA_Status = UartDMAsuccess; U1TxBufferPtrOUT = U1TxBufferPtrIN; } else{ Error_Handler(); /* Transfer error in transmission process */ HAL_UART_Transmit_DMA_Status = UartDMAfailed; } } }}�?�?�?�?�?�?

[Davydenko.Sergey]

Posted on February 07, 2017 at 15:39

Good afternoon.

It seems I have encountered the same problem ...There is no need to modify the HAL code.You must enable global interrupt USART1Good luck.

[Gln]

Posted on February 07, 2017 at 18:47

Hi

Min-Kyoung Kim,

The HAL code does not need to be modified. Make sure to call

HAL_UART_IRQHandler(&UartHandle)

inside your

USART1_IRQHander()

before doing another

HAL_UART_Transmit_DMA()

:

void USART1_IRQHandler(void)
{
 HAL_UART_IRQHandler(&UartHandle); // Should reset gState to HAL_UART_STATE_READY
 HAL_UART_Transmit_DMA(&UartHandle, buffer, BUFFER_SIZE);
}�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?

Guillaume

[Min-Kyoung Kim]

Posted on February 09, 2017 at 13:02

- where can I put your function? 

- where can I get 'DMABufHasData' ?

[T J]

Posted on February 09, 2017 at 13:13

I constantly check the 'DMABufHasData' code within the foreground main loop;

after I add bytes to the DMA buffer with puts(string), I set the flag 'DMABufHasData' true from anywhere in the code..

the foreground loop will send the data out instantly..

ie

while (1){

                delayCounter++;         // small delay loop                if ( delayCounter > 0x0ff){                   delayCounter = 0;

            checkBackgroundServices();        //  Uart1RxPort, TxDMA, RxDMA etc.

         }

}

[Min-Kyoung Kim]

Posted on February 09, 2017 at 14:13

you mean that i should  'SET_BIT(huart1.Instance->CR1, USART_CR1_RXNEIE);' after

'HAL_UART_Transmit_DMA

'

???

[Min-Kyoung Kim]

Posted on February 09, 2017 at 14:24

It works!!!!!

should I put your code before 'HAL_UART_Transmit_DMA'? 

[Gln]

Posted on February 09, 2017 at 21:34

Which part of my code exactly? In the example I posted, HAL_UART_Transmit_DMA() is called in the IRQHandler, you could also call that function in HAL_UART_TxCpltCallback() or in your main code if you look for a flag. Just make sure

HAL_UART_IRQHandler() is called BEFORE.

[Min-Kyoung Kim]

Posted on February 09, 2017 at 22:12

It is right that

HAL_UART_Transmit_DMA() is called in the IRQHandler.

I mean your code is below.

HAL_UART_IRQHandler(&UartHandle); 

I put this code in USART1_IRQHandler and put it before

HAL_UART_Transmit_DMA