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STM32F4 NUCLEO-F429ZI Unable to Communicate with HMI via RS232/RS485

QuangIoT
Associate II

 

I am facing an issue connecting the STM32F4 NUCLEO-F429ZI board to an HMI screen that uses RS232 and RS485 communication standards. The HMI can communicate successfully with my computer, but the STM32 board cannot communicate with the computer except through UART3 and using a direct cable connection. This prevents me from establishing communication between the STM32 board and the HMI screen.

Could you please help me identify what might be causing this issue and how I can resolve it?

Thank you!

16 REPLIES 16

@QuangIoT wrote:

 

I have tested the STM32 separately with the computer, but the STM32 does not receive the messages sent from the computer.

So, as @SofLit says, you need to address that first - before adding the complications of the "HMI display"

 


@QuangIoT wrote:
I have tried debugging both the hardware and software.

So what, exactly, have you done? What have you observed? What have you learned about what's going on?

 


@QuangIoT wrote:
Communication Interfaces
RS232: Supports serial communication
RS485: For industrial environments requiring differential signaling
TTL UART: 3.3V level UART communication
Baud Rate: Configurable, typically 9600 to 115200 bps

So 3 different options for the connection - are you sure you're using the correct one, and the configuration is correct?


@QuangIoT wrote:

 I still have the transmission cable plugged in.


You need to provide what you are using as cable? could you please share an image please? the connection between the Nucleo and the computer?

To give better visibility on the answered topics, please click on "Accept as Solution" on the reply which solved your issue or answered your question.
QuangIoT
Associate II

9f9efb5c81e13abf63f0.jpg

I'm using this cable and i ensure correct communication standard

You've already said the following:


@QuangIoT wrote:

I'm using USART 3 with my computer via STLINK and communication is normal, but if I switch to using USART2 (PD5 is TX and PD6 is RX) and of course the code will also change from uart3 to uart2 but it won't transmit. receive. 


If you are using USART2 with STLINK Virtual Comport, that will not going to work as that UART is not connected to the STLINK VIRTUAL comport as shown in the schematics I shared before.

So you need to use an external USB-to-UART module that will be connected to PD5 and PD6.

You need also to probe Tx and Rx with a logic analyzer or an oscilloscope to check where it goes wrong.

To give better visibility on the answered topics, please click on "Accept as Solution" on the reply which solved your issue or answered your question.

@QuangIoT wrote:

I'm using this cable and i ensure correct communication standard


That's the USB cable which connects the ST-Link to your computer.

That's what carries the debug/programming connection, and the VCP (Virtual COM Port)

As pointed out by @SofLit, that VCP is connected to USART3 (PD8 & PD9) on the STM32F4 microcontroller.

So, if you want to use USART3 to communicate with any external device, you are first going to have to disconnect it from the ST-Link VCP - that's what the SB5 & SB6 links are for:

AndrewNeil_0-1732614281721.png

AndrewNeil_1-1732614678241.png

https://www.st.com/resource/en/user_manual/um1974-stm32-nucleo144-boards-mb1137-stmicroelectronics.pdf#page=1

AndrewNeil_2-1732614918993.png

 

 

Of course, once you've disconnected them from the ST-Link, then you will no longer be able to communicate over the VCP - you will need a separate USB-to-UART converter.

Similarly, if you use any other UART connection than PD8 & PD9, that will not be connected to the ST-Link and, therefore, will not be accessible via the ST-Link's VCP -  so you will, again, need a separate USB-to-UART converter.

 

QuangIoT
Associate II

i transmitted/received data from stm32 to my computer however, i transmitted "123" but stm32 received "67 B3 06". I used uart 2(PD5 Tx, PA3 Rx)

ReceiveReceiveTransmitTransmit

 

 

 

 

 

 

 

/* USER CODE BEGIN Header */
/**
  ******************************************************************************
  * @file           : main.c
  * @brief          : Main program body
  ******************************************************************************
  * @attention
  *
  * Copyright (c) 2024 STMicroelectronics.
  * All rights reserved.
  *
  * This software is licensed under terms that can be found in the LICENSE file
  * in the root directory of this software component.
  * If no LICENSE file comes with this software, it is provided AS-IS.
  *
  ******************************************************************************
  */
/* USER CODE END Header */
/* Includes ------------------------------------------------------------------*/
#include "main.h"
#include "string.h"

/* Private includes ----------------------------------------------------------*/
/* USER CODE BEGIN Includes */

/* USER CODE END Includes */

/* Private typedef -----------------------------------------------------------*/
/* USER CODE BEGIN PTD */

/* USER CODE END PTD */

/* Private define ------------------------------------------------------------*/
/* USER CODE BEGIN PD */

/* USER CODE END PD */

/* Private macro -------------------------------------------------------------*/
/* USER CODE BEGIN PM */

/* USER CODE END PM */

/* Private variables ---------------------------------------------------------*/

ETH_TxPacketConfig TxConfig;
ETH_DMADescTypeDef  DMARxDscrTab[ETH_RX_DESC_CNT]; /* Ethernet Rx DMA Descriptors */
ETH_DMADescTypeDef  DMATxDscrTab[ETH_TX_DESC_CNT]; /* Ethernet Tx DMA Descriptors */

ETH_HandleTypeDef heth;

UART_HandleTypeDef huart2;
UART_HandleTypeDef huart3;
UART_HandleTypeDef huart6;

PCD_HandleTypeDef hpcd_USB_OTG_FS;

/* USER CODE BEGIN PV */

/* USER CODE END PV */

/* Private function prototypes -----------------------------------------------*/
void SystemClock_Config(void);
static void MX_GPIO_Init(void);
static void MX_ETH_Init(void);
static void MX_USART3_UART_Init(void);
static void MX_USB_OTG_FS_PCD_Init(void);
static void MX_USART2_UART_Init(void);
static void MX_USART6_UART_Init(void);
/* USER CODE BEGIN PFP */

/* USER CODE END PFP */

/* Private user code ---------------------------------------------------------*/
/* USER CODE BEGIN 0 */

uint8_t RxData[1] = {0};

//uint8_t RxData[9];

void HAL_UART_RxCpltCallback(UART_HandleTypeDef *huart)
{
	HAL_UART_Receive_IT(&huart6, RxData, 9);
}

/* USER CODE END 0 */

/**
  * @brief  The application entry point.
  * @retval int
  */
int main(void)
{

  /* USER CODE BEGIN 1 */

  /* USER CODE END 1 */

  /* MCU Configuration--------------------------------------------------------*/

  /* Reset of all peripherals, Initializes the Flash interface and the Systick. */
  HAL_Init();

  /* USER CODE BEGIN Init */

  /* USER CODE END Init */

  /* Configure the system clock */
  SystemClock_Config();

  /* USER CODE BEGIN SysInit */

  /* USER CODE END SysInit */

  /* Initialize all configured peripherals */
  MX_GPIO_Init();
  MX_ETH_Init();
  MX_USART3_UART_Init();
  MX_USB_OTG_FS_PCD_Init();
  MX_USART2_UART_Init();
  MX_USART6_UART_Init();
  /* USER CODE BEGIN 2 */

  HAL_UART_Receive_IT(&huart6, RxData, 9);

  /* USER CODE END 2 */

  /* Infinite loop */
  /* USER CODE BEGIN WHILE */
  while (1)
  {
    /* USER CODE END WHILE */

    /* USER CODE BEGIN 3 */

	  if(HAL_UART_Receive(&huart2, RxData, sizeof(RxData), 1000) == HAL_OK){
		  HAL_UART_Transmit(&huart3, RxData, sizeof(RxData), 1000);
	  }

  }
  /* USER CODE END 3 */
}

/**
  * @brief System Clock Configuration
  * @retval None
  */
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 RCC Oscillators according to the specified parameters
  * in the RCC_OscInitTypeDef structure.
  */
  RCC_OscInitStruct.OscillatorType = RCC_OSCILLATORTYPE_HSE;
  RCC_OscInitStruct.HSEState = RCC_HSE_BYPASS;
  RCC_OscInitStruct.PLL.PLLState = RCC_PLL_ON;
  RCC_OscInitStruct.PLL.PLLSource = RCC_PLLSOURCE_HSE;
  RCC_OscInitStruct.PLL.PLLM = 4;
  RCC_OscInitStruct.PLL.PLLN = 168;
  RCC_OscInitStruct.PLL.PLLP = RCC_PLLP_DIV2;
  RCC_OscInitStruct.PLL.PLLQ = 7;
  if (HAL_RCC_OscConfig(&RCC_OscInitStruct) != HAL_OK)
  {
    Error_Handler();
  }

  /** Initializes the CPU, AHB and APB buses 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_DIV4;
  RCC_ClkInitStruct.APB2CLKDivider = RCC_HCLK_DIV2;

  if (HAL_RCC_ClockConfig(&RCC_ClkInitStruct, FLASH_LATENCY_5) != HAL_OK)
  {
    Error_Handler();
  }
}

/**
  * @brief ETH Initialization Function
  *  None
  * @retval None
  */
static void MX_ETH_Init(void)
{

  /* USER CODE BEGIN ETH_Init 0 */

  /* USER CODE END ETH_Init 0 */

   static uint8_t MACAddr[6];

  /* USER CODE BEGIN ETH_Init 1 */

  /* USER CODE END ETH_Init 1 */
  heth.Instance = ETH;
  MACAddr[0] = 0x00;
  MACAddr[1] = 0x80;
  MACAddr[2] = 0xE1;
  MACAddr[3] = 0x00;
  MACAddr[4] = 0x00;
  MACAddr[5] = 0x00;
  heth.Init.MACAddr = &MACAddr[0];
  heth.Init.MediaInterface = HAL_ETH_RMII_MODE;
  heth.Init.TxDesc = DMATxDscrTab;
  heth.Init.RxDesc = DMARxDscrTab;
  heth.Init.RxBuffLen = 1524;

  /* USER CODE BEGIN MACADDRESS */

  /* USER CODE END MACADDRESS */

  if (HAL_ETH_Init(&heth) != HAL_OK)
  {
    Error_Handler();
  }

  memset(&TxConfig, 0 , sizeof(ETH_TxPacketConfig));
  TxConfig.Attributes = ETH_TX_PACKETS_FEATURES_CSUM | ETH_TX_PACKETS_FEATURES_CRCPAD;
  TxConfig.ChecksumCtrl = ETH_CHECKSUM_IPHDR_PAYLOAD_INSERT_PHDR_CALC;
  TxConfig.CRCPadCtrl = ETH_CRC_PAD_INSERT;
  /* USER CODE BEGIN ETH_Init 2 */

  /* USER CODE END ETH_Init 2 */

}

/**
  * @brief USART2 Initialization Function
  *  None
  * @retval None
  */
static void MX_USART2_UART_Init(void)
{

  /* USER CODE BEGIN USART2_Init 0 */

  /* USER CODE END USART2_Init 0 */

  /* USER CODE BEGIN USART2_Init 1 */

  /* USER CODE END USART2_Init 1 */
  huart2.Instance = USART2;
  huart2.Init.BaudRate = 115200;
  huart2.Init.WordLength = UART_WORDLENGTH_8B;
  huart2.Init.StopBits = UART_STOPBITS_1;
  huart2.Init.Parity = UART_PARITY_NONE;
  huart2.Init.Mode = UART_MODE_TX_RX;
  huart2.Init.HwFlowCtl = UART_HWCONTROL_NONE;
  huart2.Init.OverSampling = UART_OVERSAMPLING_16;
  if (HAL_UART_Init(&huart2) != HAL_OK)
  {
    Error_Handler();
  }
  /* USER CODE BEGIN USART2_Init 2 */

  /* USER CODE END USART2_Init 2 */

}

/**
  * @brief USART3 Initialization Function
  *  None
  * @retval None
  */
static void MX_USART3_UART_Init(void)
{

  /* USER CODE BEGIN USART3_Init 0 */

  /* USER CODE END USART3_Init 0 */

  /* USER CODE BEGIN USART3_Init 1 */

  /* USER CODE END USART3_Init 1 */
  huart3.Instance = USART3;
  huart3.Init.BaudRate = 115200;
  huart3.Init.WordLength = UART_WORDLENGTH_8B;
  huart3.Init.StopBits = UART_STOPBITS_1;
  huart3.Init.Parity = UART_PARITY_NONE;
  huart3.Init.Mode = UART_MODE_TX_RX;
  huart3.Init.HwFlowCtl = UART_HWCONTROL_NONE;
  huart3.Init.OverSampling = UART_OVERSAMPLING_16;
  if (HAL_UART_Init(&huart3) != HAL_OK)
  {
    Error_Handler();
  }
  /* USER CODE BEGIN USART3_Init 2 */

  /* USER CODE END USART3_Init 2 */

}

/**
  * @brief USART6 Initialization Function
  *  None
  * @retval None
  */
static void MX_USART6_UART_Init(void)
{

  /* USER CODE BEGIN USART6_Init 0 */

  /* USER CODE END USART6_Init 0 */

  /* USER CODE BEGIN USART6_Init 1 */

  /* USER CODE END USART6_Init 1 */
  huart6.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();
  }
  /* USER CODE BEGIN USART6_Init 2 */

  /* USER CODE END USART6_Init 2 */

}

/**
  * @brief USB_OTG_FS Initialization Function
  *  None
  * @retval None
  */
static void MX_USB_OTG_FS_PCD_Init(void)
{

  /* USER CODE BEGIN USB_OTG_FS_Init 0 */

  /* USER CODE END USB_OTG_FS_Init 0 */

  /* USER CODE BEGIN USB_OTG_FS_Init 1 */

  /* USER CODE END USB_OTG_FS_Init 1 */
  hpcd_USB_OTG_FS.Instance = USB_OTG_FS;
  hpcd_USB_OTG_FS.Init.dev_endpoints = 4;
  hpcd_USB_OTG_FS.Init.speed = PCD_SPEED_FULL;
  hpcd_USB_OTG_FS.Init.dma_enable = DISABLE;
  hpcd_USB_OTG_FS.Init.phy_itface = PCD_PHY_EMBEDDED;
  hpcd_USB_OTG_FS.Init.Sof_enable = ENABLE;
  hpcd_USB_OTG_FS.Init.low_power_enable = DISABLE;
  hpcd_USB_OTG_FS.Init.lpm_enable = DISABLE;
  hpcd_USB_OTG_FS.Init.vbus_sensing_enable = ENABLE;
  hpcd_USB_OTG_FS.Init.use_dedicated_ep1 = DISABLE;
  if (HAL_PCD_Init(&hpcd_USB_OTG_FS) != HAL_OK)
  {
    Error_Handler();
  }
  /* USER CODE BEGIN USB_OTG_FS_Init 2 */

  /* USER CODE END USB_OTG_FS_Init 2 */

}

/**
  * @brief GPIO Initialization Function
  *  None
  * @retval None
  */
static void MX_GPIO_Init(void)
{
  GPIO_InitTypeDef GPIO_InitStruct = {0};
/* USER CODE BEGIN MX_GPIO_Init_1 */
/* USER CODE END MX_GPIO_Init_1 */

  /* GPIO Ports Clock Enable */
  __HAL_RCC_GPIOC_CLK_ENABLE();
  __HAL_RCC_GPIOH_CLK_ENABLE();
  __HAL_RCC_GPIOA_CLK_ENABLE();
  __HAL_RCC_GPIOB_CLK_ENABLE();
  __HAL_RCC_GPIOD_CLK_ENABLE();
  __HAL_RCC_GPIOG_CLK_ENABLE();

  /*Configure GPIO pin Output Level */
  HAL_GPIO_WritePin(GPIOB, LD1_Pin|LD3_Pin|LD2_Pin, GPIO_PIN_RESET);

  /*Configure GPIO pin Output Level */
  HAL_GPIO_WritePin(USB_PowerSwitchOn_GPIO_Port, USB_PowerSwitchOn_Pin, GPIO_PIN_RESET);

  /*Configure GPIO pin : USER_Btn_Pin */
  GPIO_InitStruct.Pin = USER_Btn_Pin;
  GPIO_InitStruct.Mode = GPIO_MODE_IT_RISING;
  GPIO_InitStruct.Pull = GPIO_NOPULL;
  HAL_GPIO_Init(USER_Btn_GPIO_Port, &GPIO_InitStruct);

  /*Configure GPIO pins : LD1_Pin LD3_Pin LD2_Pin */
  GPIO_InitStruct.Pin = LD1_Pin|LD3_Pin|LD2_Pin;
  GPIO_InitStruct.Mode = GPIO_MODE_OUTPUT_PP;
  GPIO_InitStruct.Pull = GPIO_NOPULL;
  GPIO_InitStruct.Speed = GPIO_SPEED_FREQ_LOW;
  HAL_GPIO_Init(GPIOB, &GPIO_InitStruct);

  /*Configure GPIO pin : USB_PowerSwitchOn_Pin */
  GPIO_InitStruct.Pin = USB_PowerSwitchOn_Pin;
  GPIO_InitStruct.Mode = GPIO_MODE_OUTPUT_PP;
  GPIO_InitStruct.Pull = GPIO_NOPULL;
  GPIO_InitStruct.Speed = GPIO_SPEED_FREQ_LOW;
  HAL_GPIO_Init(USB_PowerSwitchOn_GPIO_Port, &GPIO_InitStruct);

  /*Configure GPIO pin : USB_OverCurrent_Pin */
  GPIO_InitStruct.Pin = USB_OverCurrent_Pin;
  GPIO_InitStruct.Mode = GPIO_MODE_INPUT;
  GPIO_InitStruct.Pull = GPIO_NOPULL;
  HAL_GPIO_Init(USB_OverCurrent_GPIO_Port, &GPIO_InitStruct);

/* USER CODE BEGIN MX_GPIO_Init_2 */
/* USER CODE END MX_GPIO_Init_2 */
}

/* USER CODE BEGIN 4 */

/* USER CODE END 4 */

/**
  * @brief  This function is executed in case of error occurrence.
  * @retval None
  */
void Error_Handler(void)
{
  /* USER CODE BEGIN Error_Handler_Debug */
  /* User can add his own implementation to report the HAL error return state */
  __disable_irq();
  while (1)
  {
  }
  /* USER CODE END Error_Handler_Debug */
}

#ifdef  USE_FULL_ASSERT
/**
  * @brief  Reports the name of the source file and the source line number
  *         where the assert_param error has occurred.
  *   file: pointer to the source file name
  *   line: assert_param error line source number
  * @retval None
  */
void assert_failed(uint8_t *file, uint32_t line)
{
  /* USER CODE BEGIN 6 */
  /* User can add his own implementation to report the file name and line number,
     ex: printf("Wrong parameters value: file %s on line %d\r\n", file, line) */
  /* USER CODE END 6 */
}
#endif /* USE_FULL_ASSERT */

 

 

 


@QuangIoT wrote:

i transmitted "123" but stm32 received "67 B3 06".


How are you observing what the STM32 received?

Receiving "junk" characters is usually due to incorrect baud rate:

https://learn.sparkfun.com/tutorials/serial-communication/all#:~:text=If%20all%20the%20receiving%20device%20sees%20on%20its%20receive%20line%20is%20garbage%2C%20check%20to%20make%20sure%20the%20baud%20rates%20match%20up

Is data sent from the STM32 to the PC similarly corrupted?

Have you used an oscilloscope or logic analyser to see what's actually happening on the wire?

 


@QuangIoT wrote:

I used uart 2(PD5 Tx, PA3 Rx)


With a separate USB-to-UART adapter, then?