STM32L4+USART+Rx+HAL-------Distortion of received data

[ControlFreak]

Hello Everyone,

I am using Nucleo-32 board in my project. I am programming USART to receive 10 character data and then transmit this 10 character data back.

Problem that I am observing is that if accidentally 11 character it is suppose to display error message after that every time I enter 10 character string, my response character shift right+1. Can someone

Please find below code:

HAL_Init();

 SystemClock_Config();

 GPIO_Toggle();

 HAL_GPIO_WritePin(GPIOB, GPIO_PIN_3, GPIO_PIN_SET);

 __HAL_RCC_USART1_CLK_ENABLE();

 UartHandle.Instance    = USART1;

 UartHandle.Init.BaudRate  = 4800;

 UartHandle.Init.WordLength = UART_WORDLENGTH_8B;

 UartHandle.Init.StopBits  = UART_STOPBITS_1;

 UartHandle.Init.Parity   = UART_PARITY_NONE;

 UartHandle.Init.HwFlowCtl = UART_HWCONTROL_NONE;

 //UartHandle.Init.OverSampling=UART_OVERSAMPLING_16;

 //UartHandle.Init.OneBitSampling=UART_ONE_BIT_SAMPLE_DISABLE;

 UartHandle.Init.Mode    = UART_MODE_TX_RX  ;

 if(HAL_UART_DeInit(&UartHandle) != HAL_OK)

 {

HAL_GPIO_WritePin(GPIOB, GPIO_PIN_3, GPIO_PIN_RESET);

 }

 if(HAL_UART_Init(&UartHandle) != HAL_OK)

 {

 HAL_GPIO_WritePin(GPIOB, GPIO_PIN_3, GPIO_PIN_RESET);

 }

 LTC_2873();

  HAL_GPIO_WritePin(GPIOB,GPIO_PIN_7,GPIO_PIN_SET); // Mode RS485

  HAL_GPIO_WritePin(GPIOC,GPIO_PIN_14,GPIO_PIN_RESET); // RS485 Terminator Enable

  HAL_GPIO_WritePin(GPIOB,GPIO_PIN_4,GPIO_PIN_SET); // RS485 Driver Enable

  HAL_UART_Transmit_IT( &UartHandle,&aTxBuffer[0],strlen((const char*)aTxBuffer));

  HAL_Delay(1000);

 while(1)

 {

 do

{

   HAL_GPIO_WritePin(GPIOB,GPIO_PIN_4,GPIO_PIN_RESET); // RS485 Receiver Enable

 HAL_Delay(20);

   while(HAL_UART_Receive_IT( &UartHandle,&aRx_Buffer[0],10)!=HAL_OK);

   HAL_Delay(20);

}while(rx_cplt!=1);

  HAL_Delay(50);

if(rx_cplt==1)

{

HAL_GPIO_WritePin(GPIOB,GPIO_PIN_4,GPIO_PIN_SET); // RS485 Driver Enable

HAL_Delay(20);

HAL_UART_Transmit_IT( &UartHandle,&aRx_Buffer[0],10);

HAL_Delay(20);

rx_cplt=0;

  }//end of if

 }//end of while(1)

}

[Tesla DeLorean]

Fixed lengths, and sequential rx and then tx, leave very little room for recovery or resync.

I'd approach this differently. Side step HAL and do a stateful byte level management in the IRQ Handler.

[ControlFreak]

Can you Please elaborate?

This is what I am seeing as to what is happening

When I send data more than 10 character, HAL Rx_IT rewrites Rx_Buffer[0] with 11 character (understandable)

But at the same time it increment value of my HAL pRxBuffPtr and then when I write again it uses this incremented value.

My question is if I use &Rx_Buffer[0] why it doesnot pick up address of Rx_buffer[0]?

Below is code which gives me better result but I still haven't being able to fix the problem entirely

 do

{

   HAL_GPIO_WritePin(GPIOB,GPIO_PIN_4,GPIO_PIN_RESET); // RS485 Receiver Enable

 HAL_Delay(2);

 HAL_UART_Receive_IT(&UartHandle,dummy_pointer,10);

   HAL_Delay(100);

   //UartHandle.pRxBuffPtr= &aRx_Buffer[0];

   HAL_Delay(50);

}while(rx_cplt!=1);

 UartHandle.pRxBuffPtr=dummy_pointer;

if(rx_cplt==1)

{

  HAL_GPIO_WritePin(GPIOB,GPIO_PIN_4,GPIO_PIN_SET); // RS485 Driver Enable

HAL_Delay(20);

HAL_UART_Transmit_IT(&UartHandle, dummy_pointer,10);

HAL_Delay(100);

HAL_UART_Transmit_IT(&UartHandle,(uint8_t*)"\r\n",strlen((const char*)"\r\n"));

HAL_Delay(20);

rx_cplt=0;

}

I am sorry I am not inclined to used DMA, as I am not 100% sure that I will not see the same problem in DMA

Please help!!