STM32G431 bug in fdcan? - no databytes send

[Tobe]

Hi,

i a trying to figure out, why my fdcan is not sending databytes. It only sends the id.

And i think i found a bug. Or maybe its just me having not enough knowledge to comprehend it.

In the function "FDCAN_CopyMessageToRAM" there is a part, where the data length is bit shifted to zero.

[Tobe]

I removed the bit shift, and the bytes are transferred to the txAddress. But still it wont send the bytes. I feel like i am on the complete wrong track? But the bitshifft still makes no sense at all to me.

 

[Karl Yamashita]

Show more relevant code. How are you initializing the FDCAN_TxHeaderTypeDef and data?

[Tobe]

I added the init code.  But cant you tell, that any uint8_t shifted 8 or more bits to the right is always 0?

[Tobe · Accepted solution]

I found the problem and fixed the issue: I was not using "FDCAN_data_length_code" for the data length.

I added this to the code to make it work using it without "FDCAN_data_length_code":

 IF it is NOT the actual "length", it should be named "lengthCode"... 👎

[Karl Yamashita]

FDCAN_CopyMessageToRAM is declared static so you shouldn't have removed static keyword to use that function.

Instead you need to use HAL_FDCAN_AddMessageToTxFifoQ

[Tobe]

Yes, but HAL is pretty bloated, and i am working on a bootloader.