canbus transmission

[gp73]

I'm using the demo board SPC560P - DISP and the example SPC560Pxx_RLA CAN Test Application for Discovery .

This Test Application use the CAN loopback, if I remove the flag of FlexCAN Enable Loopback in the can configuration setting I'm expecting to see the correct logic value (digital side, not after transceiver) of frame transmission on the pin 109 (CANTXD).

But I only see a noise an this pin every time there's an attempt of transmitting something.

So something in the configuration of the pin is wrong, but I don't know the correct setting.

Thanks to those who will be able to help me.

[BEdel.1]

Hi gp73,

look here: https://community.st.com/s/question/0D50X0000ArRejNSQS/spc570-can-outputs-bad-frame-independent-of-frame-parameters

It is the SPC570S-DISP board but your description sounds similar.

Best regards

Ben

[gp73 · Accepted solution]

Thanks,

yesterday I solved the problem, it was enough to correctly manage the OBE (output buffer enable) bit by removing the check mark.

Obviously when the pin is used in alternating mode, the output buffer enable must be disabled.