topic How detect an Acknowledge Frame Error under listen-only mode with MSCAN in MPC5xxx

How detect an Acknowledge Frame Error under listen-only mode with MSCAN

aitordarriba — Thu, 16 Mar 2017 13:51:45 GMT

Hi,

Currently I am working on a CAN Bus supervisor based on a MPC5125. Currently I am facing problems trying to detect the Acknowledge Error Frame on the bus when only are present a transmitter and my supervisor on listen-only mode so nobody is answering. I have notice that on the FlexCAN exists a specific register to store this information but I cant found nothing similar on the MSCAN. Anybody knows how detect this situation?

Thanks in advance.

Re: How detect an Acknowledge Frame Error under listen-only mode with MSCAN

Pavel — Mon, 20 Mar 2017 04:32:52 GMT

The MPC5125 MSCAN does not have a specific register to store information if the AcknowledgeError Frame is received.

The MPC5125 MSCAN provides only error counters for transmitter and receiver.

Have a great day,
Pavel Chubakov

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Re: How detect an Acknowledge Frame Error under listen-only mode with MSCAN

aitordarriba — Mon, 20 Mar 2017 15:33:52 GMT

Thank you for your fast answer Pavel.

So this means that I cant detect a no-acknowledge situation on the bus with the MSCAN, isn't? Doesn't exist any other solution? Is my only option use another controller like the FlexCAN one?

Regards,

Aitor Darriba

Re: How detect an Acknowledge Frame Error under listen-only mode with MSCAN

uditsalunke — Fri, 24 Mar 2017 07:33:57 GMT

Aitor,

I see BOFFHOLD bit in CANMISC register which could solve your problem. Before going to LISTEN mode micro can set and check baud rate (125,250,500) matching with the Bus Baud rate. once matching baud rate found; you can switch to LISTEN mode.

Any way, "Bus monitor" shall have AUTO baud detection; to start the BUS sniffing.

Udit S.