bit timing issue in CANFD

[VPras]

Hi,

i have STM32H7 Nucleo board, i'm trying to implement CAN-FD. so i was trying to send some data over CAN-FD to CAN-Analyser. For bit timing calculation i'm using STM32H743I-EVAL example as reference .

fdcan_ker_ck - 20Mhz, Time_quantum- 50ns, Propagation_segment- 23 tq, Phase_segment_1- 8 tq, Phase_segment_2- 8 tq, Synchronization_Jump_width - 8 tq, Bit_length - 2 us, Bit_rate- 0.5 MBit/s.

this i used it for both nominal and data..But when i use it can analyser the bit timing doesn't match.i used these following documents for reference but still couldn't solve it

https://www.can-cia.org/fileadmin/resources/documents/proceedings/2013_hartwich_v2.pdf

https://www.stmicroelectronics.com.cn/content/ccc/resource/training/technical/product_training/group0/8b/ec/0c/16/9d/fa/49/59/STM32G4-Peripheral-Flexible_Datarate_Controller_Area_Network_FDCAN/files/STM32G4-Peripheral-Flexible_Datarate_Controller_Area_Network_FDCAN.pdf/_jcr_content/translations/en.S...

Thanks,

Vimal

[VPras]

Hi,

I'm getting some data in analyser but couldn't able to decode the data, this is because of bit timing issue or anything else. i'm attaching the screenshot, please have a look into it.

Auto-retransmission is happening because my Nucleo-board is not getting any acknowledgement

Thanks,

Vimal

[VPras]

Hi,

Issue solved, there is issue with the crystal oscillator.Now it works fine with internal oscillator.

thanks,

Vimal

[VAgga]

Hi VPras,

I am also facing the same issue. Bit timings are not matching when i see it in the oscilloscope. I am using NUCLEO-H743ZI board provided by ST partner.

Should i change the crystal oscillator on the board? Board is provided by ST partner, then how can this be the issue of the crystal oscillator?

Any help would be highly appreciated.