How to filter more than 16 CAN IDs in STM32U5 FDCAN hardware filters?

[Furkan2]

Hello,

I am working on STM32U5G7VJT6 with FDCAN1 peripheral.
In CubeMX I configured 8 Extended Filters, and in my code I set them as dual filters. That gives me a total of 16 CAN IDs that can be allowed by hardware.

Now my application requires filtering of around 50 unique Extended IDs. Since the hardware allows only 8 filters (dual = 16 IDs), I am not sure how to configure this efficiently for 50 IDs.

My questions are

1. Is there a way to extend the number of hardware filters beyond 8 (e.g., using extended, or any advanced setting)?

2. If not, what is the recommended approach for applications needing more than 16 IDs? Should I:

   • Use a broader mask in hardware filters (to accept a group of IDs), and then filter the exact IDs in software?

   • Or is there another technique for optimizing FDCAN filters for larger ID sets?

Any suggestions or example implementations would be really helpful.

Thanks in advance!

[mƎALLEm]

Hello,

First, in next time please don't post screenshots for your code, but copy paste it in the discussion using </> button.

Second, try to find a common bits having the same values between these IDs and group them using Mask ID filter to simplify the filtering config. That will decrease considerably the number of filters used.