CAN FD multiple MCUs

Arjun_Bansal · ‎2023-11-08

I am trying to connect 2 NUCLEO-G0B1RET6 boards,using CAN FD. I previously did it using CAN, But now i am trying to connect these boards using CAN FD. So far no success,I want to know if it is possible to do it using CANFD.Kindly help me in this regard.

Arjun_Bansal · ‎2023-11-15

Issue solved.

I upload the updated code,with exact desired output.
This project was built using 2nos. G0B1RE, BD41041FJ-C CAN Transceiver
Solution:There is need of typeCasting,configure filter id carefully to do this.

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SofLit · ‎2023-11-08

Hello,

Sure you can do it but you should add a FDCAN transceiver to each board.

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Arjun_Bansal · ‎2023-11-08

i am using ROHM41041 transceiver on both boards.please let me know if there is any tutorial for this.I am trying since 3days with no success.

SofLit · ‎2023-11-08

Sorry I didn't find that transceiver on internet. Do you have its datasheet?

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Arjun_Bansal · ‎2023-11-08

Thanks for the attention, I have attached the datasheet.

SofLit · ‎2023-11-08

Thanks for the sharing.

Now there are three points to check:

1- If you are using HSI as source of clock please change it and use STLINK-MCO as source clock (precise clock) and configure HSE in bypass mode.

2- According to the transceiver datasheet it cannot exceed 1M/s as CAN bitrate. So if you are exceeding this bitrate with FDCAN you will surely face issues.

3- Check the state of STB pin. STB pin should be at 0 level otherwise it will be in standby mode so the node will be offline.

Hope it helps.

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Arjun_Bansal · ‎2023-11-08

I will look into it,and try configuring IOC file again.I hope this works.I will let you know about result.Sigining out now.Thanks for insight.

SofLit · ‎2023-11-08

Another important point to consider:

From your tranceiver datasheet: it's a 5V one (VCC Min: 4.75V, Max: 5.25V)

If I consider you supply it with around 5V, you have an issue with TxD pin minimum 'High level input voltage':

VIHmin = 0.7 x VCC = 3.5V > IO voltage level provided by the STM32G0 pin (@3.3V).

Even with VCCmin: VIHmin = 0.7 x 4.75 = 3,325V really at the limit!

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Arjun_Bansal · ‎2023-11-08

What would be your suggestion to overcome this problem?

SofLit · ‎2023-11-08

Simply use 3.3V transceiver or use voltage level shifter for the final project.

But for testing I think there is an internal pull-up resistor connected to the transceiver TxD pin:

Try to configure CAN_Tx pin in Open Drain. But I cannot guarantee this workaround.

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