Is a CAN Transceiver needed for a NUCLEO-F446RE?

[drtarr]

That's basically it.  I'm thrown off because this page explicitly says it has a 'CAN FD Transceiver', however, nothing says CAN on the silkscreen and this graphic I found:

Refers to the D14 and D15 pins as "CAN TD" and "CAN RD", which I assume is TX and RX implying that I would need a transceiver (CAN uses CAN High and CAN Low).

Am I right in understanding that I need a MCP2551 or similar transceiver despite what the product description page says?

[Andrew Neil]

Have you looked at the schematics? Is a transceiver present?

And the User Manual ?

[SofLit]

Hello,

There is no CAN transceiver on NUCLEO-F446RE board. "CAN TD" and "CAN RD" are just for CAN_Tx and CAN_Rx pins of the STM32 CAN peripheral and not CAN_H and CAN_L.

If you need to use CAN in normal mode you need to add a CAN transceiver. For example as you stated MCP2551. Also SN65HVD230 is another option.

Otherwise you can use CAN in loopback mode without any transceiver and you don't need any CAN bus to be established. 

Hope that answers your question.

[Andrew Neil]

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@SofLit wrote:

There is no CAN transceiver on NUCLEO-F446RE board ... If you need to use CAN in normal mode you need to add a CAN transceiver. .

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So the Product Page is misleading.

Also the Data Brief:

[SofLit]

@Andrew Neil ,

DB mentions it's specific for some boards:

And it seems NUCLEO-C092RC board  has indeed a CAN transceiver: 

I think the board is not yet available on the market, but according to the image from CubeMx:

The transceiver is there:

The board status is marked as Coming soon.

[Andrew Neil]

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@SofLit wrote:

DB mentions it's specific for some boards:

OK, but that still leaves the Product Page incorrect - which is what initially confused @drtarr 

[SofLit]

The information could be inherited from that board (NUCLEO-C092RC) as NUCLEO-xxx are almost generic.

I don't know how these pages are built but anyway I will see internally how to manage this.

[Andrew Neil]

Ah, to be fair the Product Page does include "Features specific to some of the boards (refer to the ordering information section of the data brief for details)"

But, as the Product Page refers specifically to just one particular board, it really should focus on just that board.

[Tesla DeLorean]

It's particularly unhelpful when 99% of the NUCLEO's lack any CAN Tranceiver, this model of F4 doesn't support FD-CAN at all.

And the NUCLEO-C092RC has zero general availability

[Tesla DeLorean]

A low cost diode based bench model would allow for quick evaluation in a tightly controlled environment.

https://www.keil.com/appnotes/files/apnt_236.pdf#page=4

The STM32F446 supports CAN 2.0 not FD modes