FDCAN - 2 Nucleo G0B1RE Board - What i am doing wrong ?

[SBrun.5]

Hello,

I am currently working with 2 Nucleo-G0B1RE board. I adapted the "FDCAN_Com_IT_2_BOARDS" from the G0C1RE-EV example.

Clocks are the same, so i think the fdcan is properly setup.

I changed the RX/TX pin from PD12/PD13 to PA11/PA12, and connected the 2 board together, without using FDCAN transceiver, just using RX/TX pin.

When using FDCAN_MODE_EXTERNAL_LOOPBACK mode, my signal looks fine, but in normal mode, i always get a bit error (first transmission).

What i am doing wrong ?

Thanks for your help

[mƎALLEm]

Dear SBrun.5,

In CAN normal mode you need to have a complete CAN bus: your board + transceiver and at least another node (with its transceiver) connected to the bus + termination resistors (120ohm x2) to establish a minimal CAN communication.

CAN is not SPI or UART. It needs a minimal hardware configuration to establish a communication. That's why there is the loopback mode to run CAN preliminary tests or debug (like your case)..