Posted on April 28, 2017 at 22:58
Hi abdou si,
I checked your other post so I notice a couple of things on the codes:
First at all, you have to configure a filter for the CAN reception and the parameters for the transmition as the STD id, Ext id, RTR, IDE and DLC, an example code is in the example projects of the STM32F3 HAL and is the following. This filter configuration allows to you to received any message, with any ID and some very important, the message is stored in FIFO0, so when you use the Receive function you should select FIFO0. From the transmition parameters the most you should take care with DLC, because it refers to data long in bytes, it must be a value from 1 to 8, and for testing keep RTR and IDE as the example. You should put this code after the CAN configuration.
CAN_FilterConfTypeDef sFilterConfig;
static CanTxMsgTypeDef TxMessage; static CanRxMsgTypeDef RxMessage;/*##-2- Configure the CAN Filter ###########################################*/
sFilterConfig.FilterNumber = 0; sFilterConfig.FilterMode = CAN_FILTERMODE_IDMASK; sFilterConfig.FilterScale = CAN_FILTERSCALE_32BIT; sFilterConfig.FilterIdHigh = 0x0000; sFilterConfig.FilterIdLow = 0x0000; sFilterConfig.FilterMaskIdHigh = 0x0000; sFilterConfig.FilterMaskIdLow = 0x0000; sFilterConfig.FilterFIFOAssignment = 0; sFilterConfig.FilterActivation = ENABLE; sFilterConfig.BankNumber = 14;if (HAL_CAN_ConfigFilter(&CanHandle, &sFilterConfig) != HAL_OK) { /* Filter configuration Error */ Error_Handler(); }/*##-3- Configure Transmission process #####################################*/ CanHandle.pTxMsg->StdId = 0x321; CanHandle.pTxMsg->ExtId = 0x01; CanHandle.pTxMsg->RTR = CAN_RTR_DATA; CanHandle.pTxMsg->IDE = CAN_ID_STD; CanHandle.pTxMsg->DLC = 2;In main source code I suggest to you the following:
Declare all the variables out of the while(1), better at begining of the main function
Keep into the while(1) just receiving data from CAN
Put an else condition for status == HAL_TIMEOUT
Change the FIFO1 to FIFO0
HAL_StatusTypeDef status;
int i=0;while (1)
{/* USER CODE END WHILE *//* USER CODE BEGIN 3 */status = HAL_CAN_Receive(&hcan, CAN_FIFO0, 100);
if (status == HAL_TIMEOUT){ while(1){}}else{ for (i=0;i<=7;i++) { printf(''CAN Receive data[%d ]: %x \n '',i,hcan.pRxMsg->Data[i]); }}
/* USER CODE END 3 */
}Other common issues are from time configurations, I suggest to you to use the CubeMX to inicialice the CAN port, in the clock tab make the configurations of the board clocks and crystals, and in Configuration tab set all the parameters well:
Some really really important is in the last image, you must to take on count that both Tx and Rx module must have the SAME configuration!, if one of them don't have the same configuration, the modules will never communicate well.
One last checking that is always important is to make sure that all the hardware is fine, remember to use the can bus chips in both modules, I'm using the
SN65HVD230 and works really fine, make sure that there is the 120ohms bus resistors, and if you have an oscilloscope check also the Tx and Rx signal, from both MCUs and in the CAN bus.
Posted on April 29, 2017 at 20:19
Hi abdou si,
For making test of CAN conmmunication you should have at least 2 CAN modules, I call them Tx and Rx (in practice them both could perform functions of sending or receiving data). One good test that I did for make sure that the CAN configuration is right is program the 2 modules with the same code, in the code when you press a button send a CAN frame, and also is always trying to receive a frame. Could you tell to me how are you testing the CAN module?
