2025-08-20 1:02 AM - edited 2025-08-20 1:06 AM
Hi,
I'm trying to communicate two microcontrollers (STM32H503CBT6 and a NUCLEO-H503RB) via FDCAN but the STM32H503CBT6 is not sending any messages.
Both have the same configuration, but the NUCLEO-H503RB can send (I have checked it with an oscilloscope).
Searching for an answer I found this question on the forum, saying that the STM32U5F7 has the FDCAN disabled by hardware and I wonder if this is the case with the STM32H503CBT6
Question: https://community.st.com/t5/stm32-mcus-products/fdcan-not-working-with-stm32u5f7/td-p/720224
Thanks!
2025-08-20 12:48 PM
We know that a NUCLEO-H503RB is a development board but what is a STM32H503CBT6?
2025-08-26 5:48 AM
It is the 48 pin microcontroller from STM32H5 series.
2025-08-26 6:04 AM
> I'm trying to communicate two microcontrollers (STM32H503CBT6 and a NUCLEO-H503RB) via FDCAN but the STM32H503CBT6 is not sending any messages.
> Both have the same configuration, but the NUCLEO-H503RB can send (I have checked it with an oscilloscope).
Have you checked the CAN Rx input at what you call "STM32H503CBT6" with a scope while the other side sends ?
And if so, what do the REC and TEC registers in the "STM32H503CBT6" CAN peripheral say ?
2025-08-26 7:23 AM
@AUJVV wrote:
It is the 48 pin microcontroller from STM32H5 series.
So it's just the microcontroller by itself and not soldered onto a custom board?
2025-08-26 11:21 PM - edited 2025-08-26 11:23 PM
the STM32H503CBT6 has a working FDCAN controller.
To help You I need more information:
1) The Nucleo-H503RB don't has a CAN Transceiver, can You show how You connected the CANBus?
2) How is the CANBus connected on You custom board (base on the STM32H503CBT6)?
2025-08-27 12:45 AM
I'm using the 2 transceivers TCAN1463-Q1 of Texas Instruments, one for the nucleo board and another for the custom board, same connection.
I was able to transmit with the custom board, but the signal looks like this:
I searched and I found out that this is probably due to the TX line, but I don't know what is causing it.
Have you ever encountered behaviour like this?
I'm clousing the post because i think that the problem is in my board.
2025-08-27 12:59 AM - edited 2025-08-27 1:11 AM
Check your HW especially the transceiver part:
Power supply (VCC), VIO pin level voltage, EN pin, Standby pin level voltage etc..: