Hi everyone,
I am currently experiencing some issues with the FDCAN interface; my setup consists of two nucleo boards (Nucleo-G0B1RE) which use FDCAN interface to communicate with each other. As transceivers I am using two ATA6563-click boards.
The clock used for FDCAN interface is PLLQ which ticks at 32MHz. The FDCAN parameters were configured using kvaser canfd timing calculator; Filters are disabled.
I’ve generated two set of parameters:
- Nominal bitrate 500 kBit/s; Data bitrate: 2MBit/s
- Nominal bitrate 500 kBit/s; Data bitrate: 4MBit/s
In both scenarios I’ve used a payload of 12 bytes and preserved the sending header:
txh_n1.Identifier = 0x1ad;
txh_n1.IdType = FDCAN_STANDARD_ID;
txh_n1.TxFrameType = FDCAN_DATA_FRAME;
txh_n1.DataLength = FDCAN_DLC_BYTES_12;
txh_n1.ErrorStateIndicator = FDCAN_ESI_ACTIVE;
txh_n1.BitRateSwitch = FDCAN_BRS_ON;
txh_n1.FDFormat = FDCAN_FD_CAN;
txh_n1.TxEventFifoControl = FDCAN_NO_TX_EVENTS;
txh_n1.MessageMarker = 0x0;and the same while loop:
bool is_different = 0;
HAL_UART_Transmit(&huart2, (uint8_t *)"Start...\r\n", 10, 100);
HAL_FDCAN_EnableTxDelayCompensation(&hfdcan1);
/* USER CODE END 2 */
/* Infinite loop */
/* USER CODE BEGIN WHILE */
while (1)
{
#if TX_NODE
//running on the transmitter board
if(HAL_FDCAN_AddMessageToTxFifoQ(&hfdcan1, &txh_n1, tx_node1) != HAL_OK) {
Error_Handler();
} else {
HAL_GPIO_TogglePin(LED_GREEN_GPIO_Port, LED_GREEN_Pin);
}
HAL_Delay(50);
#else
//running on the receiving board
is_different = false;
memset(&rx_node1, 0, 12 * sizeof(uint8_t));
if(HAL_FDCAN_GetRxMessage(&hfdcan1, FDCAN_RX_FIFO0, &rxh_n1, rx_node1) == HAL_OK) {
for(uint8_t idx = 0; idx < 12 && !is_different; idx++) {
if(rx_node1[idx] != tx_node1[idx])
is_different = true;
}
if(!is_different) {
HAL_GPIO_TogglePin(LED_GREEN_GPIO_Port, LED_GREEN_Pin);
HAL_UART_Transmit(&huart2, (uint8_t *)"OK\r\n", 4, 100);
} else {
HAL_UART_Transmit(&huart2, (uint8_t *)"BAD\r\n", 5, 100);
}
}
HAL_Delay(10);
#endif
/* USER CODE END WHILE */
/* USER CODE BEGIN 3 */
}Now, I am facing the following issue. In the first scenario everything works as intended. I receive all the transmitted data.
In the second one (where the bitrate is 4Mbit/s) with the transmitter in normal mode, the receiver node doesn’t receive anything. Switching the transmitter to external loopback, the receiver node receives all the data, as seen in the following images:
4Mbit normal mode
At 2Mbits everything works as intended. Changing from 2 to 3 or 4 Mbits in normal mode the transmitting board stops transmitting data after arbitration. Switching to external loopback, all the data arrives on the receiver node.
Does someone know what is happening there, why it happens and how can it be solved?
Regards,
Liviu
