UART/USART Does not Work

[akoluacik]

I would like to transmit data via USART and read the data sent to computer via a terminal(I have tried Putty and Real Term so far). To that end, I activate My USART configuration is seen as above. I also wrote the code below:

uint8_t myTxData[13] = "Hello World\r\n";
while (1)
  {
    /* USER CODE END WHILE */
 
    /* USER CODE BEGIN 3 */
 	  HAL_StatusTypeDef res = HAL_UART_Transmit(&huart1, myTxData, 13, 10);
	  if(!res) {
		  HAL_GPIO_TogglePin(GPIOI, GPIO_PIN_1);
		  HAL_Delay(1000);
	  }
  }

Note that I only put here inside the while loop. The other statements were generated by CubeMX.

Normally my code sends data to my pc if res is true, in other words, if it is HAL_OK, and also toggles the LED. Since it couldn't see the data in the terminal, I changed the condition in if statement, and saw that the led is toggled in each second. Therefore, I concluded that my USART channel does not work. What's the issue?

Thx for your help in advance.

[akoluacik]

I am using STM32F746NG Discovery board. I changed timeout to 100 as you said, and tried more different values, i.e., HAL_MAX_DELAY. But still does not work.

My RCC setting is that I enabled HSE and configured max frequency value, which 216 kHz.

[gbm · Accepted solution]

Your program runs on STM32F746, not on ST-Link CPU (STM32F103, which uses its PA2 and PA3 to connect to F746). The schematics of Discovery board shows the pins used in F746 for UART VCP connection are PA9 and PB7, which are USART1 TX and RX pins.

[Anil3]

Hi @Anıl Koluaçık​ 

Try to use CDC_Transmit_FS function as you are using the COM Port

[Piranha]

Writing "u" instead of "you" and inability of splitting the thought to sentences really is an indicator...

[akoluacik]

Thank you sooo much. This solves my problem. I have a question, how did you determine that the correct ones are PA9 and PB7? I looked at the datasheet more times but I couldn't determine it.

[Piranha]

Datasheet, reference manual etc. are for a microcontroller. Board features are documented in board's user manual and schematic.

[Piranha]

MHz, kHz... The units doesn't matter, do they? ;)

[nayanag]

 In schematic PA9 and PB7 are not mentioned as USART Tx and Rx pins, is it available in user manual?

I am using STM32L552 board, which are the USART1 Tx and Rx pins.

[waclawek.jan]

Please don't hijack others threads. Start your own, stating the STM32 and hardware you are using, and the problem you came across. You can link to this thread if you think it's relevant.

JW