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STM32f407G-DISC1 : USART loopback using HAL functions and cubeMX

VTOL_Aviations
Associate II

I want to send 10 bytes of data through UART loopback by interrupt mode. Though I'm able to receive the data, I don't understand why my HAL_UART_RxCpltCallback() is not getting executed. But my HAL_UART_TxCpltCallback(), is getting executed every time after a byte of data is transferred. I've generated code through cubeMX. I've enabled the USART2 global interrupt. My Control Register(CR1) for my USART2 is 0x300c. That is, UE,M,TE,RE bits are only set. The TXIE, TCIE bits are NOT set in the CR1 Register. Now, What does "global" in global interrupt mean here? Does that mean an interrupt is generated from any one of the 10 sources(mentioned in the data sheet like, Tx complete, Rx buffer full etc)?

None of the bits corresponding to interrupts are enabled in CR1 register. But the control is going to HAL_UART_TxCpltCallback() every time it transfers a byte of data. Why does this happen?

Please unveil the mystery.

Below is my code.

UART_HandleTypeDef huart2;

void SystemClock_Config(void);

static void MX_GPIO_Init(void);

static void MX_USART2_UART_Init(void);

uint8_t tx_data[] = {0,1,2,3,4,5,6,7,8,9};

uint8_t rx_data[10];

int main(void)

{

  int i=0;

  HAL_Init();

  SystemClock_Config();

  MX_GPIO_Init();

  MX_USART2_UART_Init();

  while (1)

  {

   HAL_UART_Transmit_IT(&huart2, &tx_data[i], 10);

   HAL_Delay(1500);

   HAL_UART_Receive_IT(&huart2, &rx_data[i] , 10);

   HAL_Delay(1500);

   if((xferCnt==10) || (rxCnt==10))

      break;

   else

      i++;

  }

 }

void HAL_UART_TxCpltCallback(UART_HandleTypeDef *huart)

{

  xferCnt++;

}

void HAL_UART_RxCpltCallback(UART_HandleTypeDef *huart)

{

  rxCnt++;

}

PS: I'm using STM32F407G-DISC1 board, Attolic Truestudio IDE, Ubuntu 16.04 OS.

1 REPLY 1
S.Ma
Principal

Unless using DMA on USART, try to use LL functions, makes the mecanics easier to master and still with low complexity, USART IP seems to be quite mature and stable, making your code quite portable across the family.