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STM32F767ZI and CAN-Bus: Bus-Off error after receiving 8 byte long message

FSchm.4
Associate II

Hello everyone,

i am currently trying to get the can bus on my Nucleo-F767ZI running.

Now i got a problem that every time i sent a message via CAN (from my PCANView) which is longer than two bytes i got a Bus-Off error, but if byte 2 is not empty i can sent messages with more bytes. Maybe someone here can explain to me what i am doing wrong. If you need everything else for helping me, i will upload the requested files.

Thank you for your time and help.

1 ACCEPTED SOLUTION

Accepted Solutions
FSchm.4
Associate II

It seems the problem was with the sample point of the CAN from 87.5% to 75% now it works with varying byte length.

Interesting is that the same code works on my Nucleo L476RG with varying byte lengths and the old sample point of 87.5%.

View solution in original post

7 REPLIES 7
FSchm.4
Associate II

This is a screenshot from the Trace Window of the PCANView:0693W00000D1UYRQA3.png

Karl Yamashita
Lead III

Edit: Scratch what i said before. Have you tried to break on the HAL_CAN_RxFifo0MsgPendingCallback to see if you are interrupting and receiving the correct ID and data?

Tips and Tricks with TimerCallback https://www.youtube.com/@eebykarl
If you find my solution useful, please click the Accept as Solution so others see the solution.

Thank for your reply,

i tried the first sugesstion from you and that did not work and

if i set a breakpoint at the HAL_CAN_RxFifo0MsgPendingCallback and step into the function,

the ID and data are correctly processed.

If you like i could upload the full project as Zip file if that helps.

Thank you for your time and help.

FSchm.4
Associate II

I tryed to check the rx_data array with live expression view.

It seem when i am sending 4 bytes that are not zero, that the upper 4 bytes are getting also filled with data. For example byte 4 to 6 are filled with 0xff and byte 7 ist filled with random numbers between 0x00 and 0xff

DCtech
Associate II

What is your DLC configuration ?

Thank you for your reply,

the tx_header.DLC ist set to 8 for the STM and the PCAN DLC is also set to 8.

FSchm.4
Associate II

It seems the problem was with the sample point of the CAN from 87.5% to 75% now it works with varying byte length.

Interesting is that the same code works on my Nucleo L476RG with varying byte lengths and the old sample point of 87.5%.