Clock Configuration for touchGFX with CAN FD on STM32H745I-DISCO

[FARAWAY]

Hello,

I am using the STM32H745I-DISCO board for my project, which requires both TouchGFX and CAN FD functionality. However, I am encountering an issue with the clock configuration.

I need to synchronize the Nominal Baud Rate to 500 kbps and the Data Baud Rate to 2000 kbps.

I configured the Nominal timing parameters as follows:

Prescaler: 4

Time Segment 1: 13

Time Segment 2: 2

SJW: 1

According to my calculations, the resulting Nominal Baud Rate should be 500 kbps, but STM32CubeIDE shows the calculated rate as 1250 kbps.

I suspect the issue lies in the Clock Configuration.
Could this be related to the FDCAN clock source or prescaler settings?

I would appreciate it if you could guide me on how to properly configure the clock settings for this use case.
Also, if there are any official documents, reference manuals, or recommended resources that explain how to correctly set up the clock configuration for FDCAN and TouchGFX on the STM32H7 series, please let me know.

Thank you in advance for your support.

[Karl Yamashita]

You need to know the FDCAN clock frequency. Then you can use this link to calculate the correct values

https://kvaser.com/support/calculators/can-fd-bit-timing-calculator/

 

[FARAWAY]

Thank you very much. That would be very helpful. 

[MHoll.2]

The timming depens on the FD CAN Input clock (in Your case this seems to be 80MHz), You can finde tis on the Clock Configuration page: