HAL_UARTEx_ReceiveToIdle_DMA() isn't working as expected

[Praneeth]

Hi Everyone, I'm using Nucleo-f429 board and using HAL UART API's on it. I have observed that on using HAL_UARTEx_ReceiveToIdle_DMA()  for a receiving data of length 800. I found that Buffer getting filled / Interrupt is called once its size reached 64 even though there isn't any idle state and regardless of what data I'm passing.  

I have tried using this API for receiving data of length 50 (<64). Its working and interrupt is getting triggered once the idle state is seen at 50th element.
Could anyone help me out on this.

Required code snippets attached below

Thanks

 

edit:

 

#define BUFFER_SIZE 1000

extern unsigned char rxData[BUFFER_SIZE];

void HAL_UART_MspInit(UART_HandleTypeDef* uartHandle)
{

GPIO_InitTypeDef GPIO_InitStruct = {0};
if(uartHandle->Instance==USART2)
{
/* USER CODE BEGIN USART2_MspInit 0 */

/* USER CODE END USART2_MspInit 0 */
/* USART2 clock enable */
__HAL_RCC_USART2_CLK_ENABLE();

__HAL_RCC_GPIOA_CLK_ENABLE();
__HAL_RCC_GPIOD_CLK_ENABLE();
/**USART2 GPIO Configuration
PA3 ------> USART2_RX
PD5 ------> USART2_TX
*/
GPIO_InitStruct.Pin = GPIO_PIN_3;
GPIO_InitStruct.Mode = GPIO_MODE_AF_PP;
GPIO_InitStruct.Pull = GPIO_NOPULL;
GPIO_InitStruct.Speed = GPIO_SPEED_FREQ_VERY_HIGH;
GPIO_InitStruct.Alternate = GPIO_AF7_USART2;
HAL_GPIO_Init(GPIOA, &GPIO_InitStruct);

GPIO_InitStruct.Pin = GPIO_PIN_5;
GPIO_InitStruct.Mode = GPIO_MODE_AF_PP;
GPIO_InitStruct.Pull = GPIO_NOPULL;
GPIO_InitStruct.Speed = GPIO_SPEED_FREQ_VERY_HIGH;
GPIO_InitStruct.Alternate = GPIO_AF7_USART2;
HAL_GPIO_Init(GPIOD, &GPIO_InitStruct);

/* USART2 DMA Init */
/* USART2_RX Init */
hdma_usart2_rx.Instance = DMA1_Stream5;
hdma_usart2_rx.Init.Channel = DMA_CHANNEL_4;
hdma_usart2_rx.Init.Direction = DMA_PERIPH_TO_MEMORY;
hdma_usart2_rx.Init.PeriphInc = DMA_PINC_DISABLE;
hdma_usart2_rx.Init.MemInc = DMA_MINC_ENABLE;
hdma_usart2_rx.Init.PeriphDataAlignment = DMA_PDATAALIGN_BYTE;
hdma_usart2_rx.Init.MemDataAlignment = DMA_MDATAALIGN_BYTE;
hdma_usart2_rx.Init.Mode = DMA_NORMAL;
hdma_usart2_rx.Init.Priority = DMA_PRIORITY_HIGH;
hdma_usart2_rx.Init.FIFOMode = DMA_FIFOMODE_ENABLE;
hdma_usart2_rx.Init.FIFOThreshold = DMA_FIFO_THRESHOLD_FULL;
hdma_usart2_rx.Init.MemBurst = DMA_MBURST_SINGLE;
hdma_usart2_rx.Init.PeriphBurst = DMA_PBURST_SINGLE;
if (HAL_DMA_Init(&hdma_usart2_rx) != HAL_OK)
{
Error_Handler();
}

__HAL_LINKDMA(uartHandle,hdmarx,hdma_usart2_rx);

/* USART2 interrupt Init */
HAL_NVIC_SetPriority(USART2_IRQn, 0, 0);
HAL_NVIC_EnableIRQ(USART2_IRQn);
/* USER CODE BEGIN USART2_MspInit 1 */

/* USER CODE END USART2_MspInit 1 */
}
}



void UART_data_Receive(void)
{
HAL_UARTEx_ReceiveToIdle_DMA(&huart2,rxData,BUFFER_SIZE);
 while(!UARTreceiveComplete){} // Waiting till the UART data is received
}


void HAL_UARTEx_RxEventCallback(UART_HandleTypeDef *huart,uint16_t Size)
{
 /* Prevent unused argument(s) compilation warning */
 UNUSED(huart);
if (huart -> Instance == USART2)
 {
HAL_GPIO_TogglePin(GPIOB, LD1_Pin); // glowing the led1 for indication of data received
UARTreceiveComplete=1; // Enabling the flag
 }
}

 

 

[TDK]

What is BUFFER_SIZE?

Probably there is an idle interrupt, or your buffer size is too small to receive everything that once. Do you have a logic analyzer to verify there is no idle time on the bus? Probably your terminal program is breaking up the message into 64 byte chunks.

[Praneeth]

I have kept BUFFER_SIZE as 1000. Currently I don't have LA plot but I have checked it before and its not idle

[TDK]

The peripheral only triggers an interrupt on (a) line IDLE, (b) half-transfer complete, and (c) full transfer complete. There is no mechanism for HAL_UARTEx_RxEventCallback to get called without one of these taking place. You can view the source code yourself to verify this.

[mƎALLEm]

Hello,

Please copy paste your code using the button </> instead of providing screenshots of your code.

Thank you for your understanding.