HAL_CAN_RxFifo0MsgPendingCallback will be triggered only when call HAL_CAN_AddTxMessge twice ?
I am using NUCLEO STM32F103RB to learn CAN communication. In CubeMX, PB8 and PB9 were set to CAN_RX and CAN_TX, the baud rate is 500kbps, standard frame, and in Loopback mode. The USB_LP_CAN1_RX0_IQRHandler and CAN1_RX1_IRQHandler were enabled. The CAN filter was set in the MX_CAN_Init():
CAN_FilterTypeDef canfilterconfig;
canfilterconfig.FilterActivation = CAN_FILTER_ENABLE;
canfilterconfig.FilterBank = 10;
canfilterconfig.FilterFIFOAssignment = CAN_RX_FIFO0;
canfilterconfig.FilterIdHigh = 0;
canfilterconfig.FilterIdLow = 0x0000;
canfilterconfig.FilterMaskIdHigh = 0;
canfilterconfig.FilterMaskIdLow = 0x0000;
canfilterconfig.FilterMode = CAN_FILTERMODE_IDMASK;
canfilterconfig.FilterScale = CAN_FILTERSCALE_32BIT;
canfilterconfig.SlaveStartFilterBank = 0;
HAL_CAN_ConfigFilter(&hcan, &canfilterconfig);
In the main.c, the data transmission is done as below:
/* start CAN communication */
HAL_CAN_Start(&hcan);
HAL_CAN_ActivateNotification(&hcan, CAN_IT_RX_FIFO0_MSG_PENDING);
TxHeader.DLC = 1; // data length is 1
TxHeader.ExtId = 0;
TxHeader.IDE = CAN_ID_STD; //standard frame
TxHeader.RTR = CAN_RTR_DATA; //data frame
TxHeader.StdId = 0x103; // ID = 0x103
TxHeader.TransmitGlobalTime = DISABLE;
TxData[0] = 0x01;
TxData[1] = 0x02;
TxData[2] = 0x03;
TxData[3] = 0x04;
if (HAL_CAN_AddTxMessage(&hcan, &TxHeader, &TxData[0], &TxMailbox) != HAL_OK)
{
Error_Handler();
}
The Callback function is defined in the main.c as below:
void HAL_CAN_RxFifo0MsgPendingCallback(CAN_HandleTypeDef *hcan)
{
HAL_CAN_GetRxMessage(hcan, CAN_RX_FIFO0, &RxHeader, RxData);
count ++;
}
I thought, since the the Tx data will be loopback to Rx in the Loopback mode, each time after the HAL_CAN_AddTxMessage is called, the HAL_CAN_RxFifo0MsgPendingCallback will be triggered.
However, in my case, the first HAL_CAN_AddTxMessage() will not trigger the callback function. Only when HAL_CAN_AddTxMessage() called twice, the callback function will be triggered, and the received data was those from the first HAL_CAN_AddTxMessage() data. And, the last HAL_CAN_AddTxMessage() will not trigger the callback function either, even after it is the endless while(1) loop.
Not sure what's the cause for this problem. Any suggestion, advice will be appreciated.