CAN NACK error

[6T9]

Hello,

I'm trying to run the flexcan_encrypted_s32k144 example project on the S32K144EVB-Q100.

CAN FD disabled and Bitrate 500kbit/s.

When I'm trying to send CAN-messages via Vector I get an the following error and no CAN-message is received on the board:

If I turn on the TX Self-ACK in vector the board receives the CAN-messages.

So I guess the ACK is not set by the board.

I connected two evalboards and they communicate without any issue between each other. Could it be that the example projects ignores the ACK?
Is there a possibility to configure to check the ACK?

Best regards

[PetrS]

Hi,

yes, per description MCU does not acknowledge incoming message properly. It could be fine if you can measure TX/RX and bus lines with scope or analyzer to know if anything is sent by MCU.

If there is ACK pulse on TX line, then most probably the CAN bit timing is not correctly set. Be sure same sample point is programmed.
If nothing is seen on TX then maybe pin configuration is wrong. 
You can also try to send anything from the MCU and see if any errors are detected.

BR, Petr

[6T9]

Hi Petr,

thanks for your answer.

I checked the lines and the MCU is sending the expected values.

Is there an opportunity to configure the MCU that it ACKs properly?

Best regards

Tom

[PetrS]

Hi,

as I wrote check CAN bit timing...

BR, Petr