CAN Bus Not Receiving Messages on STM32F4 + TJA1050 (CJMCU-230)

[hamza_enes]

I'm trying to set up CAN communication between two STM32F4 boards using CJMCU-230 transceivers, but I'm not receiving any messages. Here's a full breakdown of the setup and what I've tried:

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Hardware Setup:

• MCU: STM32F4 Discovery (hcan1)

• Transceiver: CJMCU-230

• Second Node: Another STM32F4 with same configuration

• Bitrate: 125 kbit/s on both ends

• Termination: 120Ω termination resistor is likely present on the transceiver (CJMCU-230) board, but not manually added externally. I haven't removed or measured it directly, but many CJMCU-230 modules include onboard termination resistors by default.

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STM32 Configuration:

txHeader.DLC = 1;
txHeader.IDE = CAN_ID_STD;
txHeader.RTR = CAN_RTR_DATA;
txHeader.StdId = 0x245;
sFilterConfig.FilterMode = CAN_FILTERMODE_IDMASK;
sFilterConfig.FilterFIFOAssignment = CAN_FILTER_FIFO0;
sFilterConfig.FilterIdHigh = 0x0000;
sFilterConfig.FilterIdLow = 0x0000;
sFilterConfig.FilterMaskIdHigh = 0x0000;
sFilterConfig.FilterMaskIdLow = 0x0000;
sFilterConfig.FilterScale = CAN_FILTERSCALE_32BIT;
sFilterConfig.FilterActivation = ENABLE; HAL_CAN_ConfigFilter(&hcan1, &sFilterConfig); HAL_CAN_Start(&hcan1); HAL_CAN_ActivateNotification(&hcan1, CAN_IT_RX_FIFO0_MSG_PENDING);

• GPIO, RCC, NVIC configurations are done correctly.

• HAL_CAN_Start() and HAL_CAN_ActivateNotification() are called.

• Transmitting messages works fine; HAL_CAN_AddTxMessage() returns HAL_OK.

The Problem:

• No CAN message is received via CAN1 RX0 interrupt. The CAN1_RX0_IRQHandler() is never triggered.

• HAL_CAN_GetRxMessage() returns HAL_ERROR when called in the main loop.

• HAL_CAN_AddTxMessage() sometimes returns HAL_ERROR in the loop, but returns HAL_OK inside an external interrupt.

• After sending ~9 messages, the internal hcan1.Instance->ESR register gives a value of 0x800003, which includes:

  • EPVF (Error Passive Flag) → CAN controller became error-passive

  • Transmission is no longer possible

• CAN messages are sent with:

  txHeader.StdId = 0x245;
  txHeader.IDE = CAN_ID_STD;
  txHeader.RTR = CAN_RTR_DATA;
  txHeader.DLC = 1;

• CAN filter is configured in mask mode, accepting all messages (all ID and mask bits set to 0).

• CAN speed: 125 kbps on both devices.

• Interrupts and NVIC configuration are properly done.

• HAL_CAN_Start() and HAL_CAN_ActivateNotification() are called.
  
  

Any ideas or guidance on how to fix this would be greatly appreciated.

[CTapp.1 · Accepted solution]

A transmitting node going error passive is a sign that there is nothing else on the bus capable of sending out "ack" bits, which makes it look like you have a transceiver or bus issue.

Have you verified that you do have termination resistors (measure the resistance between the CAN high and low)?

Have you used a 'scope or logic analyser to see what is getting onto the bus?

[hamza_enes]

Thanks a lot for your detailed reply and guidance!

You were absolutely right — the problem was with the transceiver. I was using a CJMCU-230 module, which apparently doesn't have a TJA1050 on it. After struggling for a while with no ACKs and constant Error Passive status on the STM32 side, I decided to replace the transceiver.

I switched to a standard TJA1050-based module, and boom — everything started working flawlessly. CAN communication is now solid, ACKs are received properly, and the bus is alive.

Your message pointed me in the right direction. Much appreciated!

[CTapp.1]

Glad it helped.

It would be great if you would accept my original post as the "Accepted solution" so that this thread shows as solved.