Hardware connection
- Node A: STM32F423RHTx, TCAN1462-Q1 transceiver, HSI→PLL→80MHz SYSCLK, 40MHz APB1, PA11/PA12
- Node B: Arduino Uno + MCP2515 breakout (8MHz xtal, onboard transceiver), mcp_can v1.5. 120Ω termination, wiring verified
- CAN Timing (both at 500kbps)
CAN Configuration
CAN_HandleTypeDef hcan1;
/* CAN1 init function */
void MX_CAN1_Init(void)
{
/* USER CODE BEGIN CAN1_Init 0 */
/* USER CODE END CAN1_Init 0 */
/* USER CODE BEGIN CAN1_Init 1 */
/* USER CODE END CAN1_Init 1 */
hcan1.Instance = CAN1;
hcan1.Init.Prescaler = 8;
hcan1.Init.Mode = CAN_MODE_NORMAL;
hcan1.Init.SyncJumpWidth = CAN_SJW_1TQ;
hcan1.Init.TimeSeg1 = CAN_BS1_6TQ;
hcan1.Init.TimeSeg2 = CAN_BS2_3TQ;
hcan1.Init.TimeTriggeredMode = DISABLE;
hcan1.Init.AutoBusOff = DISABLE;
hcan1.Init.AutoWakeUp = ENABLE;
hcan1.Init.AutoRetransmission = DISABLE;
hcan1.Init.ReceiveFifoLocked = DISABLE;
hcan1.Init.TransmitFifoPriority = DISABLE;
if (HAL_CAN_Init(&hcan1) != HAL_OK)
{
Error_Handler();
}
/* USER CODE BEGIN CAN1_Init 2 */
CAN_FilterTypeDef canfilterconfig;
canfilterconfig.FilterBank = 0;
canfilterconfig.FilterMode = CAN_FILTERMODE_IDMASK;
canfilterconfig.FilterScale = CAN_FILTERSCALE_32BIT;
canfilterconfig.FilterIdHigh = 0x0000;
canfilterconfig.FilterIdLow = 0x0000;
canfilterconfig.FilterMaskIdHigh = 0x0000;
canfilterconfig.FilterMaskIdLow = 0x0000;
canfilterconfig.FilterFIFOAssignment = CAN_RX_FIFO0;
canfilterconfig.FilterActivation = CAN_FILTER_ENABLE;
canfilterconfig.SlaveStartFilterBank = 14;
if (HAL_CAN_ConfigFilter(&hcan1, &canfilterconfig) != HAL_OK)
{
Error_Handler();
}
/* USER CODE END CAN1_Init 2 */
}
Notification is also enabled.
if (HAL_CAN_ActivateNotification(&hcan1, CAN_IT_RX_FIFO0_MSG_PENDING) != HAL_OK)
{
Error_Handler();
}
Callback function
CAN_RxHeaderTypeDef gRxHeader;
uint8_t gRxData[8];
void HAL_CAN_RxFifo0MsgPendingCallback(CAN_HandleTypeDef *hcan)
{
printf("Hi from CB\r\n");
if (HAL_CAN_GetRxMessage(&hcan1, CAN_RX_FIFO0, &gRxHeader, gRxData) == HAL_OK){
printf("ID: 0x%03lX DLC: %lu Data:", gRxHeader.StdId, gRxHeader.DLC);
for (uint8_t i = 0; i < gRxHeader.DLC; i++){
printf(" %02X", gRxData[i]);
}
printf("\r\n");
}
}
What Works
- STM32 → Arduino: Arduino serial monitor shows received frames every 1 second
- STM32 Loopback mode: receives own frames internally
- STM32 register dump: IER=0x02 (FMPIE0 armed), MSR shows normal mode, filter active
What Doesn't Work
- Arduino → STM32: RF0R.FMP permanently 0, REC=0, interrupt never fires
- Arduino sendMsgBuf returns CAN_SENDMSGTIMEOUT (7), EFLG=0x15 (TXEP+TXWAR+EWARN)
- STM32's own TX frames show ACK Error (LEC=0x3) and TERR0=1 despite Arduino claiming to receive them — ACK contradiction
I have tried changing the filter configuration still that didn't worked.
