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[SOLVED] Change the uart pins and afterwards, i get wrong value...why?

RComa.1
Associate II

‎2021-10-19 03:42 AM

Hi folk, how's tricks?

i need some help from you happens following:

I have a UART3, but this UART work's on PORTB and PORTC pins, so i need to use this uart some times on PORTC and other times on PORTC, so i reconfigure the ports in runtime to get this, however i get a wrong value form PORTC when i try to change the UART port from B PORT to C PORT..., in the C PORT i have a sensor thant send a specific value, but it's wrong when i reconfigure the ports...i don't know why...this is my code:

GPIO_InitTypeDef def,def2,def3,def4;
 
  HAL_GPIO_DeInit(GPIOB,GPIO_PIN_11); 
  HAL_GPIO_DeInit(GPIOB,GPIO_PIN_10);
 
/*RECONFIGURE THIS PORTB (uart) TO TURN IT INTO AN OUTPUT PORT
   def3.Pull = GPIO_PULLDOWN;
   def3.Mode = GPIO_MODE_OUTPUT_PP;
   def3.Pin = GPIO_PIN_11;
   def3.Speed = GPIO_SPEED_FREQ_HIGH;
   HAL_GPIO_Init(GPIOB,&def3);
 
   def4.Pull = GPIO_PULLDOWN;
   def4.Mode = GPIO_MODE_OUTPUT_PP;
   def4.Pin = GPIO_PIN_10;
   def4.Speed = GPIO_SPEED_FREQ_HIGH;
   HAL_GPIO_Init(GPIOB,&def4);
 
 
/*RECONFIGURE THIS PORTC (reset state) TO TURN IT INTO A UART3 PORT FROM NOW ON...
  RCC->APB2ENR |=  (1<<4);  //Enable PORTC's clock
 
  def.Alternate = GPIO_AF7_USART3;
  def.Pull = GPIO_NOPULL;
  def.Mode = GPIO_MODE_AF_OD;
  def.Pin = GPIO_PIN_11;
  def.Speed = GPIO_SPEED_FREQ_HIGH;
  HAL_GPIO_Init(GPIOC,&def);
 
  HAL_Delay(100);
  def2.Alternate = GPIO_AF7_USART3;
  def2.Pull = GPIO_NOPULL;
  def2.Mode = GPIO_MODE_AF_OD;
  def2.Pin = GPIO_PIN_10;
  def2.Speed = GPIO_SPEED_FREQ_HIGH;
  HAL_GPIO_Init(GPIOC,&def2);
 
 
  HAL_UART_Receive_IT(&huart3, inputBufferUARTPM, 10); //Get the first trace

Apparently it'work...becaus ei get data from the C port, but it's wrong data...

Thanks in advance

Regards.

SOLUTION:

Just put __HAL_UART_DISABLE(&huart); before reconfigure ports and afterwards, just put __HAL_UART_ENABLE(&huart3);

Thanks!

Regards.

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Andrew Neil
Evangelist III

‎2021-10-19 04:21 AM

@RComa.1​ - "in the C PORT i have a sensor thant send a specific value,"

You need to give more details on that - what kind of sensor? what is it sending? what kind of interface?

A schematic (aka "circuit diagram") would help.

" but it's wrong"

In what way(s), exactly, is it "wrong"? How are you observing this? What investigation/testing/debugging have you done to find what's going on?

Do you have an oscilloscope or logic analyser to see what's happening on the wires?

"when i reconfigure the ports"

So look at what happens when you change the ports - is the configuration for the sensor maintained correctly?

EDIT

Previous thread:

https://community.st.com/s/question/0D53W000019CsapSAC/how-to-use-a-same-uart-for-two-devices

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