STM32F0 Correct way to use HAL_UART_Receive_IT?

seed · ‎2015-09-09

Posted on September 09, 2015 at 11:02

Hi,

I have read some of the previous related issues, but I am still confused. How do I use the uart interrupts in a correct way (using hal)? I need to receive each single character since don't know the length.

I have modified the UART TwoBoards_ComIT example to a dummy rx application that doesn't do anything except beeing in receive mode. The application will get stuck if I send more than 3 characters(I tested from realTerm). Sending each character one by one works fine.

while(1)

{

UartReady = RESET;

if(HAL_UART_Receive_IT(&UartHandle, (uint8_t *)aRxBuffer, 1) != HAL_OK)

{

Error_Handler();

}

while (UartReady != SET)

{

BSP_LED_On(LED2);

HAL_Delay(100);

BSP_LED_Off(LED2);

HAL_Delay(100);

BSP_LED_On(LED2);

HAL_Delay(100);

BSP_LED_Off(LED2);

HAL_Delay(500);

}

void HAL_UART_RxCpltCallback(UART_HandleTypeDef *UartHandle)

{

UartReady = SET;

}

Amel NASRI · ‎2015-09-09

Posted on September 09, 2015 at 11:43

Hi Seed,

It is not so clear how ''The application will get stuck if you send more than 3 characters'':

- at which level exactly?

- are there any error flag set in USART registers?

- isn't the problem root cause coming from transmitter side?

-Mayla-

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seed · ‎2015-09-09

Posted on September 09, 2015 at 14:00

Hi,

Sorry for the bad description of the problem. It does not get stuck. I get buffer overflow error reported in HAL_UART_IRQHandler and HAL_UART_ErrorCallback is called. If I send 3 bytes I get buffer overflow using receive size 1, but if I change the code below to receive 3 bytes(HAL_UART_Receive_IT(&UartHandle, (uint8_t *)aRxBuffer, 3) ) I do not get buffer overflow. I will investigate futher, but I guess it is not reading fast enough and then I guess I need to modify hal implementation? Any suggestions?

/Jonas

seed · ‎2015-09-10

Posted on September 10, 2015 at 09:47

Hi,

It seems like the hal implementation for uart IT not inted for the use case if you do not know the length of the reciving bytes. I will go for the DMA solution using circular buffer mode then I don't think I need to patch the hal implementation.