CAN-bus with STM32F103RB

Kenno · ‎2024-06-13

Hello there!

I am trying to use some STM32F103RB Nucleoboards and some MCP2551 chips to make a CAN-bus. I got this problem where I can make it work in loop-back mode, but I cannot send from one board, to another one. I know the Circuit is stable and correctly weird, so I have deduced that it must be a problem with the code. I've provided a ZIP-file with the code that my group and I've made, and also some pictures of the setup in case you can spot anything wrong that I could not. We are somewhat sure that making a CAN-bus with STM32F103RB is impossible, but if any of you know what we're doing wrong, or if we are correct.

The code can be found in this DropBoxLink: https://www.dropbox.com/scl/fi/125mbvictjg6wwqbqnetw/CAN_BUS_KODE_BILLEDER_GRUPPE18.zip?rlkey=1z9k88380m35oaivu0i774j30&dl=0

Reciver code:

/* 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"

/* 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 ---------------------------------------------------------*/
CAN_HandleTypeDef hcan;

/* USER CODE BEGIN PV */

/* USER CODE END PV */

/* Private function prototypes -----------------------------------------------*/
void SystemClock_Config(void);
static void MX_GPIO_Init(void);
static void MX_CAN_Init(void);
/* USER CODE BEGIN PFP */

/* USER CODE END PFP */

/* Private user code ---------------------------------------------------------*/
/* USER CODE BEGIN 0 */
CAN_TxHeaderTypeDef TxHeader;
CAN_RxHeaderTypeDef RxHeader;

uint8_t TxData[8];
uint8_t RxData[8];

uint32_t TxMailbox;

int datacheck = 0;


void HAL_CAN_RxFifo1MsgPendingCallback(CAN_HandleTypeDef *hcan)
{
	HAL_CAN_GetRxMessage(hcan, CAN_RX_FIFO0, &RxHeader, RxData);
	if (RxHeader.DLC == 2)
	{
		datacheck = 1;
	}
}
/* 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_CAN_Init();
  /* USER CODE BEGIN 2 */
  HAL_CAN_Start(&hcan);

    // Activate the notification
    HAL_CAN_ActivateNotification(&hcan, CAN_IT_RX_FIFO0_MSG_PENDING);


    TxHeader.DLC = 2;  // data length
    TxHeader.IDE = CAN_ID_STD;
    TxHeader.RTR = CAN_RTR_DATA;
    TxHeader.StdId = 0x103;  // ID

    TxData[0] = 50;
    TxData[1] = 20;

  /* USER CODE END 2 */

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

    /* USER CODE BEGIN 3 */
	  HAL_Delay (1000);

	  	  if (datacheck == 1)
	  	  {
	  		  // blink the LED
	  		  for (int i=0; i<RxData[1]; i++)
	  		  {
	  			  HAL_GPIO_TogglePin(GPIOA, GPIO_PIN_5);
	  			  HAL_Delay(RxData[0]);
	  		  }

	  		  datacheck = 0;

	  		  HAL_CAN_AddTxMessage(&hcan, &TxHeader, TxData, &TxMailbox);

	  	  }
  }
  /* USER CODE END 3 */
}

/**
  * @brief System Clock Configuration
  * @retval None
  */
void SystemClock_Config(void)
{
  RCC_OscInitTypeDef RCC_OscInitStruct = {0};
  RCC_ClkInitTypeDef RCC_ClkInitStruct = {0};

  /** 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_ON;
  RCC_OscInitStruct.HSEPredivValue = RCC_HSE_PREDIV_DIV1;
  RCC_OscInitStruct.HSIState = RCC_HSI_ON;
  RCC_OscInitStruct.PLL.PLLState = RCC_PLL_ON;
  RCC_OscInitStruct.PLL.PLLSource = RCC_PLLSOURCE_HSE;
  RCC_OscInitStruct.PLL.PLLMUL = RCC_PLL_MUL9;
  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_DIV2;
  RCC_ClkInitStruct.APB2CLKDivider = RCC_HCLK_DIV1;

  if (HAL_RCC_ClockConfig(&RCC_ClkInitStruct, FLASH_LATENCY_2) != HAL_OK)
  {
    Error_Handler();
  }
}

/**
  * @brief CAN Initialization Function
  * @PAram None
  * @retval None
  */
static void MX_CAN_Init(void)
{

  /* USER CODE BEGIN CAN_Init 0 */

  /* USER CODE END CAN_Init 0 */

  /* USER CODE BEGIN CAN_Init 1 */

  /* USER CODE END CAN_Init 1 */
  hcan.Instance = CAN1;
  hcan.Init.Prescaler = 18;
  hcan.Init.Mode = CAN_MODE_NORMAL;
  hcan.Init.SyncJumpWidth = CAN_SJW_1TQ;
  hcan.Init.TimeSeg1 = CAN_BS1_1TQ;
  hcan.Init.TimeSeg2 = CAN_BS2_2TQ;
  hcan.Init.TimeTriggeredMode = DISABLE;
  hcan.Init.AutoBusOff = DISABLE;
  hcan.Init.AutoWakeUp = DISABLE;
  hcan.Init.AutoRetransmission = DISABLE;
  hcan.Init.ReceiveFifoLocked = DISABLE;
  hcan.Init.TransmitFifoPriority = DISABLE;
  if (HAL_CAN_Init(&hcan) != HAL_OK)
  {
    Error_Handler();
  }
  /* USER CODE BEGIN CAN_Init 2 */

  CAN_FilterTypeDef canfilterconfig;

  canfilterconfig.FilterActivation = CAN_FILTER_ENABLE;
  canfilterconfig.FilterBank = 10;  // which filter bank to use from the assigned ones
  canfilterconfig.FilterFIFOAssignment = CAN_FILTER_FIFO0;
  canfilterconfig.FilterIdHigh = 0x446<<5;
  canfilterconfig.FilterIdLow = 0;
  canfilterconfig.FilterMaskIdHigh = 0x446<<5;
  canfilterconfig.FilterMaskIdLow = 0x0000;
  canfilterconfig.FilterMode = CAN_FILTERMODE_IDMASK;
  canfilterconfig.FilterScale = CAN_FILTERSCALE_32BIT;
  canfilterconfig.SlaveStartFilterBank = 0;  // doesn't matter in single can controllers

  HAL_CAN_ConfigFilter(&hcan, &canfilterconfig);
  /* USER CODE END CAN_Init 2 */

}

/**
  * @brief GPIO Initialization Function
  * @PAram 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_GPIOB_CLK_ENABLE();
  __HAL_RCC_GPIOA_CLK_ENABLE();
  __HAL_RCC_GPIOD_CLK_ENABLE();

  /*Configure GPIO pin Output Level */
  HAL_GPIO_WritePin(GPIOA, GPIO_PIN_5, GPIO_PIN_RESET);

  /*Configure GPIO pin : PC13 */
  GPIO_InitStruct.Pin = GPIO_PIN_13;
  GPIO_InitStruct.Mode = GPIO_MODE_INPUT;
  GPIO_InitStruct.Pull = GPIO_NOPULL;
  HAL_GPIO_Init(GPIOC, &GPIO_InitStruct);

  /*Configure GPIO pin : PA5 */
  GPIO_InitStruct.Pin = GPIO_PIN_5;
  GPIO_InitStruct.Mode = GPIO_MODE_OUTPUT_PP;
  GPIO_InitStruct.Pull = GPIO_NOPULL;
  GPIO_InitStruct.Speed = GPIO_SPEED_FREQ_LOW;
  HAL_GPIO_Init(GPIOA, &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.
  * @PAram  file: pointer to the source file name
  * @PAram  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 */

Sender code:

/* 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"

/* 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 ---------------------------------------------------------*/
CAN_HandleTypeDef hcan;

/* USER CODE BEGIN PV */

/* USER CODE END PV */

/* Private function prototypes -----------------------------------------------*/
void SystemClock_Config(void);
static void MX_GPIO_Init(void);
static void MX_CAN_Init(void);
/* USER CODE BEGIN PFP */

/* USER CODE END PFP */

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

CAN_TxHeaderTypeDef TxHeader;
CAN_RxHeaderTypeDef RxHeader;

uint8_t TxData[8];
uint8_t RxData[8];

uint32_t TxMailbox;
int datacheck = 0;


void HAL_GPIO_EXTI_Callback(uint16_t GPIO_Pin)
{
	if (GPIO_Pin == GPIO_PIN_13)
	{
		TxData[0] = 100;   // ms Delay
		TxData[1] = 40;    // loop rep

		HAL_CAN_AddTxMessage(&hcan, &TxHeader, TxData, &TxMailbox);
	}
}


void HAL_CAN_RxFifo0MsgPendingCallback(CAN_HandleTypeDef *hcan)
{
	HAL_CAN_GetRxMessage(hcan, CAN_RX_FIFO0, &RxHeader, RxData);
	if (RxHeader.DLC == 2)
	{
		datacheck = 1;
	}
}


/* 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_CAN_Init();
  /* USER CODE BEGIN 2 */


  HAL_CAN_Start(&hcan);

  // Activate the notification
   HAL_CAN_ActivateNotification(&hcan, CAN_IT_RX_FIFO0_MSG_PENDING);


   TxHeader.DLC = 2;  // data length
   TxHeader.IDE = CAN_ID_STD;
   TxHeader.RTR = CAN_RTR_DATA;
   TxHeader.StdId = 0x446;  // ID



  /* USER CODE END 2 */

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

	   if(HAL_GPIO_ReadPin(GPIOC, GPIO_PIN_13) == GPIO_PIN_SET){
  		   HAL_GPIO_WritePin(GPIOA, GPIO_PIN_5, GPIO_PIN_RESET);
		    TxData[0] = 100;   // ms Delay
		    TxData[1] = 40;    // loop rep
		   HAL_CAN_AddTxMessage(&hcan, &TxHeader, TxData, &TxMailbox);

	   }
	   else{
		   HAL_GPIO_WritePin(GPIOA,GPIO_PIN_5, GPIO_PIN_SET); //
		    TxData[0] = 100;   // ms Delay
		    TxData[1] = 40;    // loop rep
		   HAL_CAN_AddTxMessage(&hcan, &TxHeader, TxData, &TxMailbox);
	   }
    /* USER CODE END WHILE */

    /* USER CODE BEGIN 3 */

 	  if (datacheck)
 	  {
 		  // blink the LED
 		  for (int i=0; i<RxData[1]; i++)
 		  {
 			  HAL_GPIO_TogglePin(GPIOA, GPIO_PIN_5);
 			  HAL_Delay(RxData[0]);
 		  }

 		  datacheck = 0;

 			TxData[0] = 100;   // ms Delay
 			TxData[1] = 40;    // loop rep

 			HAL_CAN_AddTxMessage(&hcan, &TxHeader, TxData, &TxMailbox);
 	  }
   }
  /* USER CODE END 3 */
}

/**
  * @brief System Clock Configuration
  * @retval None
  */
void SystemClock_Config(void)
{
  RCC_OscInitTypeDef RCC_OscInitStruct = {0};
  RCC_ClkInitTypeDef RCC_ClkInitStruct = {0};

  /** 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_ON;
  RCC_OscInitStruct.HSEPredivValue = RCC_HSE_PREDIV_DIV1;
  RCC_OscInitStruct.HSIState = RCC_HSI_ON;
  RCC_OscInitStruct.PLL.PLLState = RCC_PLL_ON;
  RCC_OscInitStruct.PLL.PLLSource = RCC_PLLSOURCE_HSE;
  RCC_OscInitStruct.PLL.PLLMUL = RCC_PLL_MUL9;
  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_DIV2;
  RCC_ClkInitStruct.APB2CLKDivider = RCC_HCLK_DIV1;

  if (HAL_RCC_ClockConfig(&RCC_ClkInitStruct, FLASH_LATENCY_2) != HAL_OK)
  {
    Error_Handler();
  }
}

/**
  * @brief CAN Initialization Function
  * @PAram None
  * @retval None
  */
static void MX_CAN_Init(void)
{

  /* USER CODE BEGIN CAN_Init 0 */

  /* USER CODE END CAN_Init 0 */

  /* USER CODE BEGIN CAN_Init 1 */

  /* USER CODE END CAN_Init 1 */
  hcan.Instance = CAN1;
  hcan.Init.Prescaler = 18;
  hcan.Init.Mode = CAN_MODE_NORMAL;
  hcan.Init.SyncJumpWidth = CAN_SJW_1TQ;
  hcan.Init.TimeSeg1 = CAN_BS1_1TQ;
  hcan.Init.TimeSeg2 = CAN_BS2_2TQ;
  hcan.Init.TimeTriggeredMode = DISABLE;
  hcan.Init.AutoBusOff = DISABLE;
  hcan.Init.AutoWakeUp = DISABLE;
  hcan.Init.AutoRetransmission = DISABLE;
  hcan.Init.ReceiveFifoLocked = DISABLE;
  hcan.Init.TransmitFifoPriority = DISABLE;
  if (HAL_CAN_Init(&hcan) != HAL_OK)
  {
    Error_Handler();
  }
  /* USER CODE BEGIN CAN_Init 2 */


  CAN_FilterTypeDef canfilterconfig;

  canfilterconfig.FilterActivation = CAN_FILTER_ENABLE;
  canfilterconfig.FilterBank = 10;  // which filter bank to use from the assigned ones
  canfilterconfig.FilterFIFOAssignment = CAN_FILTER_FIFO0;
  canfilterconfig.FilterIdHigh = 0x103<<5;
  canfilterconfig.FilterIdLow = 0;
  canfilterconfig.FilterMaskIdHigh = 0x103<<5;
  canfilterconfig.FilterMaskIdLow = 0x0000;
  canfilterconfig.FilterMode = CAN_FILTERMODE_IDMASK;
  canfilterconfig.FilterScale = CAN_FILTERSCALE_32BIT;
  canfilterconfig.SlaveStartFilterBank = 0;  // how many filters to assign to the CAN1 (master can)

  HAL_CAN_ConfigFilter(&hcan, &canfilterconfig);


  /* USER CODE END CAN_Init 2 */

}

/**
  * @brief GPIO Initialization Function
  * @PAram 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_GPIOB_CLK_ENABLE();
  __HAL_RCC_GPIOA_CLK_ENABLE();
  __HAL_RCC_GPIOD_CLK_ENABLE();

  /*Configure GPIO pin Output Level */
  HAL_GPIO_WritePin(GPIOA, GPIO_PIN_5, GPIO_PIN_RESET);

  /*Configure GPIO pin : PC13 */
  GPIO_InitStruct.Pin = GPIO_PIN_13;
  GPIO_InitStruct.Mode = GPIO_MODE_INPUT;
  GPIO_InitStruct.Pull = GPIO_NOPULL;
  HAL_GPIO_Init(GPIOC, &GPIO_InitStruct);

  /*Configure GPIO pin : PA5 */
  GPIO_InitStruct.Pin = GPIO_PIN_5;
  GPIO_InitStruct.Mode = GPIO_MODE_OUTPUT_PP;
  GPIO_InitStruct.Pull = GPIO_NOPULL;
  GPIO_InitStruct.Speed = GPIO_SPEED_FREQ_LOW;
  HAL_GPIO_Init(GPIOA, &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.
  * @PAram  file: pointer to the source file name
  * @PAram  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 */

Any help with this would be much appreciated. The TL;DR of what we're doing is:
When you press a button, a message is being sent over the CAN-network and which is then being detected by the other STM32F103, which then makes an LED light up.

We REALLY want it to work with this specific hardware.

Thank you for taking your time and helping me, it is MUCH appreciated.

SofLit · ‎2024-06-18

Hello,

First, to share something please attach it directly in the thread instead of using dropbox or similar..

Second, the first thing I verified is the bitrate config you set:

  hcan.Init.Prescaler = 18;
  hcan.Init.TimeSeg1 = CAN_BS1_1TQ;
  hcan.Init.TimeSeg2 = CAN_BS2_2TQ;

To me these are bad parameters you set. You need to decrease as much as possible the prescaler and increase as much as possible BS1 and BS2 with a sampling point ~(70% to 85%) of the bit time. You need to provide your ioc file to help you to select the best parameters fitting your bitrate.

Still some questions to answer:

As I understood, you have an issue with Tx and you said that in loopback mode, it worked fine but in normal mode not. Are you sure you have configured the same bitrate at both sides (the two available nodes on the bus)?

What about the transceiver? the image you attached doesn't give information but you need to provide a sketch or schematics to check the HW. What about the terminating resistors? how did you power the transceiver knowing that it's a 5V chip. What about Rs pin voltage level of MCP2551 which needs to be at least tied to the ground!

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.

View solution in original post

SofLit · ‎2024-06-18