MCP2551 High-Speed CAN Transceiver with Blue Pill using STM32CubeIDE

Prerequisites

This project assumes you have already installed STM32CubeIDE. You need to have previously done a basic blink sketch with blue-pill using STM32CubeIDE. I have made a complete video from installing STM32CubeIDE to LED blink program. You can watch it by clicking this link. https://www.youtube.com/watch?v=kXg467nVd_A

Wiring Diagram

Transmitter Module

STM32CubeIDE Settings

Click RCC → High Speed Clock (HSE) to Crystal/Ceramic Resonator

Click Clock Configuration tab → HCLK (MHz) to 72

Click Pinout and Configuration tab

Click connectivity --> Click CAN --> Mode --> Activated

Parameter Settings --> Prescalor 72 & Time Quanta in Bit Segment1 - 2 Times (Baud 125000)

Set PB9 to CAN_TX (PB8 will auto set to CAN_RX)

ADC1 - IN9 (tick)

Parameter Settings --> ADC Settings --> Continuous Conversion Mode (Enabled)

Click Clock Configuration tab → Set ADC Prescalor to /6

Additional code on top of STM32CubeIDE generated code for Transmitter

/* USER CODE BEGIN 0 */
uint16_t readValue;
CAN_TxHeaderTypeDef TxHeader;
uint32_t TxMailbox;
uint8_t TxData[8]="NIZAR---";
/* USER CODE END 0 */

  /* USER CODE BEGIN 2 */
  HAL_ADC_Start(&hadc1);
  HAL_CAN_Start(&hcan);
  TxHeader.DLC = 8;  // data length
  TxHeader.IDE = CAN_ID_STD;
  TxHeader.RTR = CAN_RTR_DATA;
  TxHeader.StdId = 0x6A5;  // ID can be between Hex1 and Hex7FF (1-2047 decimal)
  /* USER CODE END 2 */

  /* Infinite loop */
  /* USER CODE BEGIN WHILE */
  while (1)
  {
    HAL_ADC_PollForConversion(&hadc1,1000);
    readValue = HAL_ADC_GetValue(&hadc1);
    // readValue is between 0-4095 but we need to transmit maximum 255 (one byte)
    // We divide readValue by 16 to get 0-255. Better way to divide is by shifting bits
    // (readValue >> 4) is same as (readValue / 16)  
    TxData[7] = readValue >> 4;
    HAL_CAN_AddTxMessage(&hcan, &TxHeader, TxData, &TxMailbox);
    HAL_Delay(1000);
    /* USER CODE END WHILE */

Receiver Module

STM32CubeIDE Settings

Click RCC → High Speed Clock (HSE) to Crystal/Ceramic Resonator

Click Clock Configuration tab → HCLK (MHz) to 72

Click Pinout and Configuration tab

Click connectivity --> Click CAN --> Mode --> Activated

Parameter Settings --> Prescalor 72 & Time Quanta in Bit Segment1 - 2 Times (Baud 125000)

NVIC Settings --> CAN RX1 Interrupt (tick)

Set PB9 to CAN_TX (PB8 will auto set to CAN_RX)

Set PC13 to GPIO_Output

Additional code on top of STM32CubeIDE generated code for Receiver

/* USER CODE BEGIN 0 */
CAN_FilterTypeDef sFilterConfig;
CAN_RxHeaderTypeDef RxHeader;
uint8_t RxData[8];
uint8_t delayLED;
void HAL_CAN_RxFifo1MsgPendingCallback(CAN_HandleTypeDef *hcan)
{
  HAL_CAN_GetRxMessage(hcan, CAN_RX_FIFO1, &RxHeader, RxData);
  delayLED = RxData[7];
}
/* USER CODE END 0 */

 /* USER CODE BEGIN 2 */
  HAL_CAN_Start(&hcan);
  // Configure the filter
  sFilterConfig.FilterActivation = CAN_FILTER_ENABLE;
  sFilterConfig.FilterFIFOAssignment = CAN_FILTER_FIFO1;
  sFilterConfig.FilterMode = CAN_FILTERMODE_IDMASK;
  sFilterConfig.FilterIdHigh = 0x6A5<<5; 
  sFilterConfig.FilterIdLow = 0;
  sFilterConfig.FilterMaskIdHigh = 0x7FF<<5; // SET 0 to unfilter
  sFilterConfig.FilterMaskIdLow = 0;
  sFilterConfig.FilterScale = CAN_FILTERSCALE_32BIT;
  HAL_CAN_ConfigFilter(&hcan, &sFilterConfig);
  // Activate the notification
  HAL_CAN_ActivateNotification(&hcan, CAN_IT_RX_FIFO1_MSG_PENDING);
  /* USER CODE END 2 */

  /* Infinite loop */
  /* USER CODE BEGIN WHILE */
  while (1)
  {
    HAL_GPIO_TogglePin(GPIOC, GPIO_PIN_13);
    HAL_Delay(delayLED);
    /* USER CODE END WHILE */