2024-12-04 08:00 AM - last edited on 2024-12-04 08:32 AM by Andrew Neil
Hello, I am interesting about CAN FD options on ST MCUs. I was working on standard CAN on STM32F103 in past and there was possible to define list of filter addresses for 28 STD addresses or 14 EXT addresses. If I've read correctly reference manuals for MCUs with CAN-FD there is usually 28 filter banks for STD addresses but only 8 filter banks for EXT addresses. Exist there some MCU type where is possible to set more as 8 filtered addresses for CAN-FD EXT addresses?
I need to set list of, at least 10, CAN FD extended addresses (but not a range of them) and I don't know if there exist a solution for this on some MCU. If there exist this kind of MCU, can you recommend a development board for this?
Thank for answer in advance.
p..s. usualy in documentation for CAN FD part is written:
"FDCAN extended message ID filter element
Up to eight filter elements can be configured for 29-bit extended IDs. When accessing an
extended message ID filter element, its address is the filter list extended start address
FLESA plus twice the index of the filter element (0 … 7)."
Solved! Go to Solution.
2024-12-04 08:13 AM - edited 2024-12-04 09:08 AM
Hello,
H7 family especially STM32H743 has the superset version of FDCAN it can support up to 64 filter elements for EXT ID:
While other MCUs have less FDCAN features like G0, G4 etc ..
Hope that answers your question.
2024-12-04 08:13 AM - edited 2024-12-04 09:08 AM
Hello,
H7 family especially STM32H743 has the superset version of FDCAN it can support up to 64 filter elements for EXT ID:
While other MCUs have less FDCAN features like G0, G4 etc ..
Hope that answers your question.
2024-12-05 04:27 AM
Hello, thank you for answer and advice but unfortunately pre price level of STM32H7 is too high in comparing to STM32G,F.
I have found the cheapest type STM32H7B0 but there is only 128kB Flash and I need at least 256kB.
It's strange that ST has this CAN FD extended addresses filtering so restricted only to 8 filters in comparing to classic CAN on older MCUs.
2024-12-05 04:46 AM - edited 2024-12-05 05:06 AM
This was a choice. More features/filters means more die size and more die size means a more expensive chip.
2024-12-05 05:11 AM
That is probably not too correct reason because there is different between CAN-FD STD and EXT address only few bits and length of DATA field is the same.
Maybe, it can be nice to add CAN-FD filters count information more visible at specification or add it as filter option in tools for selction of MCUs.
Thank you for answer, I will look for other options...
2024-12-05 05:19 AM - edited 2024-12-05 05:25 AM
@RKast.1 wrote:
That is probably not too correct reason because there is different between CAN-FD STD and EXT address only few bits and length of DATA field is the same....
Sorry? more CAN filters means more memory size allocated on the chip. More bits means more memory cells ..The memory has its own foot print size on the die area and this impacts the price. No matter extended or standard filters.
2024-12-05 05:57 AM
No, I am not talking about adding more filters. Based on STD or EXT choice of filter, the same CAN data memory can be used which is already reserved for each filter and different is only if one filter banks (11bits) is used for CAN ID or 2 filter banks (29bits) to filter CAN address. It works this way on stm32F103 but for classic CAN.
But it does not matter, I have to take it as it is designed.
Thank you for support,