FDCAN availability on STM32H747I-DISCO board

[prashanth1]

Moved from this thread.

Thanks for the previous response — it helped me understand the configuration better.

 

Now I have a follow-up doubt:

 

In STM32CubeIDE, I can see multiple pin options for FDCAN1_RX and FDCAN1_TX in the pinout view. However, when I checked the STM32H747I-DISCO board, those selected pins (e.g., PB8, PB9, etc.) don’t seem to be accessible via any header pins or exposed GPIOs on the board.

 

So my question is:

Are there any accessible pins on the STM32H747I-DISCO board that I can actually use to connect FDCAN1 to an external CAN transceiver like the TJA1051T/3?

 

Would appreciate any guidance — especially if there's a known method to access these signals (e.g., via Arduino headers, PMOD, or solder points).

 

Thanks!

 

 

[mƎALLEm]

Hello,

The only solution for FDCAN1 usage on this board is to use STMOD+ connector where PB8 (FDCAN1_Rx) and PB9 (FDCAN1_Tx) are available on pins 19 and 20. From the board's user manual UM2411:

From the board's schematic:

Unfortunately, FDCAN2 is not an alternative as all the pins are already used externally by some hardware.

Hope that answers your question.

[Andrew Neil]

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@mƎALLEm wrote:

Unfortunately, FDCAN2 is not an alternative as all the pins are already used externally by some hardware.

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@prashanth1 this is always the trouble on dev boards with many bundled "extras";  particularly displays - which can be very hungry on pins!

For better access to the chip itself, maybe look at a Nucleo board - they are far simpler, so don't use-up so many pins...

[mƎALLEm]

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@Andrew Neil wrote:

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 particularly displays - which can be very hungry on pins!

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Particularly for this board, it's mostly the external memory over FMC (SDRAM) which is consuming the IOs the most. The display in this board is driven over DSI interface (only 8-9 pins):