Not receiving data on PC com(RS232) port, when transmitting data from STM32F407VG DISCOVERY board (Using Baseboard STM32F4 DIS-BB RS232 port ie COM1)

Hello,

I am facing trouble in sending data out from STM32F407VG Discovery board (connected to base board) using UART6 (J1 and J2 jumpers are connected). 

Connected the Tx pin of RS232 port on baseboard to PC COM port Rx pin and sending data periodically. I have enabled DMA on the board and program is in FreeRTOS.

Using baud rate 115200 at both ends, 8 bits no parity, 1 stop bit.

(Using code generated using CubeMX 5.1.0 and added my code on top of it) 

Using Atollic TrueSTUDIO® for STM32, Built on Eclipse Neon.1a. Version: 9.0.1 Build id: 20180420-1214

On the receiving side, have a blocking receive call which waits for each byte (Linux) as below which is tested with some other program and working:

 read(fd,arg_buf,1);

 // arg_buf is char array pointer

The receiving side remains blocked not receiving any data. That is the issue.

Checked similar issues on forum to no avail.

Code brief (STM32 code on FreeRTOS):

-------------------------------------

#include "main.h"
#include "cmsis_os.h"
--
--
UART_HandleTypeDef huart2;
UART_HandleTypeDef huart6;
DMA_HandleTypeDef hdma_usart6_rx;
DMA_HandleTypeDef hdma_usart6_tx;
 
 
osThreadId defaultTaskHandle;
TaskHandle_t Handle;
  
void SystemClock_Config(void);
 static void MX_GPIO_Init(void);
 static void MX_DMA_Init(void);
 static void MX_USART2_UART_Init(void);
 static void MX_USART6_UART_Init(void);
 
void StartDefaultTask(void const * argument);
 void Task1(void *pvParameters)
 {
 	volatile TickType_t StartTime, EndTime, ExecutionTime, Time_value;
 	TickType_t xLastWakeTime;
 	const TickType_t xPeriod = pdMS_TO_TICKS( 10 );
 
 xLastWakeTime = xTaskGetTickCount();
  while(1)
  {
  StartTime = xTaskGetTickCount();
  ----
  ----
 		if( HAL_UART_Transmit_DMA(&huart6, tx_pos, 16)!= HAL_OK )
 		{
 			 Error_Handler();
 		}
  ----
  vTaskDelayUntil( &xLastWakeTime, xPeriod );
  }
 }
 
 
int main(void)
 {
  
  HAL_Init();
  SystemClock_Config();
 
  if( xTaskCreate( Task1, "Task1", 500, NULL, 1, &Handle ) != pdPASS)
  {
  	 return 0;
  }
   
 /* Initialize all configured peripherals */
  MX_GPIO_Init();
  MX_DMA_Init();
  MX_USART2_UART_Init();
  MX_USART6_UART_Init();
  osThreadDef(defaultTask, StartDefaultTask, osPriorityNormal, 0, 128);
  defaultTaskHandle = osThreadCreate(osThread(defaultTask), NULL);
  osKernelStart();
  while (1)
  {
 
 }
}
 
void SystemClock_Config(void)
{
 
 RCC_OscInitTypeDef RCC_OscInitStruct = {0};
 RCC_ClkInitTypeDef RCC_ClkInitStruct = {0};
 /* Configure the main internal regulator output voltage */
  __HAL_RCC_PWR_CLK_ENABLE();
  __HAL_PWR_VOLTAGESCALING_CONFIG(PWR_REGULATOR_VOLTAGE_SCALE1);
  /* Initializes the CPU, AHB and APB busses clocks */
  RCC_OscInitStruct.OscillatorType = RCC_OSCILLATORTYPE_HSI;
  RCC_OscInitStruct.HSIState = RCC_HSI_ON;
  RCC_OscInitStruct.HSICalibrationValue = RCC_HSICALIBRATION_DEFAULT;
  RCC_OscInitStruct.PLL.PLLState = RCC_PLL_ON;
  RCC_OscInitStruct.PLL.PLLSource = RCC_PLLSOURCE_HSI;
  RCC_OscInitStruct.PLL.PLLM = 8;
  RCC_OscInitStruct.PLL.PLLN = 50;
  RCC_OscInitStruct.PLL.PLLP = RCC_PLLP_DIV2;
  RCC_OscInitStruct.PLL.PLLQ = 4;
  if (HAL_RCC_OscConfig(&RCC_OscInitStruct) != HAL_OK)
  {
  Error_Handler();
  }
 
 /** Initializes the CPU, AHB and APB busses clocks */
  
 RCC_ClkInitStruct.ClockType = RCC_CLOCKTYPE_HCLK|RCC_CLOCKTYPE_SYSCLK|RCC_CLOCKTYPE_PCLK1|RCC_CLOCKTYPE_PCLK2;
  
 RCC_ClkInitStruct.SYSCLKSource = RCC_SYSCLKSOURCE_PLLCLK;
 RCC_ClkInitStruct.AHBCLKDivider = RCC_SYSCLK_DIV1;
 RCC_ClkInitStruct.APB1CLKDivider = RCC_HCLK_DIV2;
 RCC_ClkInitStruct.APB2CLKDivider = RCC_HCLK_DIV1;
 
 if (HAL_RCC_ClockConfig(&RCC_ClkInitStruct, FLASH_LATENCY_1) != HAL_OK)
 {
 Error_Handler();
 }
}
 
static void MX_USART6_UART_Init(void)
{
 d.Instance = USART6;
 huart6.Init.BaudRate = 115200;
 huart6.Init.WordLength = UART_WORDLENGTH_8B;
 huart6.Init.StopBits = UART_STOPBITS_1;
 huart6.Init.Parity = UART_PARITY_NONE;
 huart6.Init.Mode = UART_MODE_TX_RX;
 huart6.Init.HwFlowCtl = UART_HWCONTROL_NONE;
 huart6.Init.OverSampling = UART_OVERSAMPLING_16;
 
 if (HAL_UART_Init(&huart6) != HAL_OK)
 {
 Error_Handler();
 }
}
static void MX_DMA_Init(void) 
{
 __HAL_RCC_DMA2_CLK_ENABLE();
  HAL_NVIC_SetPriority(DMA2_Stream1_IRQn, 5, 0);
  HAL_NVIC_EnableIRQ(DMA2_Stream1_IRQn);
  HAL_NVIC_SetPriority(DMA2_Stream6_IRQn, 5, 0);
  HAL_NVIC_EnableIRQ(DMA2_Stream6_IRQn); 
}

Thank you