TMS570LS1224: Can not get CAN Controller to Bus OFF State, TEC State gets stuck at 128

Jens Benner

Part Number: TMS570LS1224
Other Parts Discussed in Thread: LAUNCHXL2-TMS57012, SN65HVD230,

Tool/software:

Hello all,

in my application I need to log the CAN Bus error conditions. Now when I trie to test my code I am not able to get the CAN controller in Bus OFF State even when I short the CAN_L / CAN_H lines. the TEC Counter does not go beyond 128. The CAN Error Notification is configured correctly since I get error and status notifiactions but the Bus OFF Flag never get set.

Any idea why the TEC state gets stuck at 128?

Kind regards
Jens

over 1 year ago

0 jagadish gundavarapu over 1 year ago

TI__Guru 70681 points

Hi Jens,

Jens Benner said:
Any idea why the TEC state gets stuck at 128?

How many CAN frames you are sending? Can i get your project for verification?

Can you please also refer below similar thread once:

(+) TMS570LS0332: For the content in the yellow box, what means can be changed according to customer needs? - Arm-based microcontrollers forum - Arm-based microcontrollers - TI E2E support forums

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Thanks & regards,
Jagadish.

0 Jens Benner over 1 year ago in reply to jagadish gundavarapu

Intellectual 330 points

Hello Jagdish,
unfortunatelly I am not allowed to share the project. This is my CAN configuration:

I use only one Mailbox for Transmit and Receive each:

We send about 1 CAN Message every 10 Seconds.

Kind Regards,

Jens

0 jagadish gundavarapu over 1 year ago in reply to Jens Benner

TI__Guru 70681 points

Hi Jens,

Apologies for the delay, this week i will test this issue at my end and will verify the behavior you are mentioning at my end as well.

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Thanks & regards,
Jagadish.

0 jagadish gundavarapu over 1 year ago in reply to jagadish gundavarapu

TI__Guru 70681 points

Hi Jens,

Apologies for the delay, today i tested by shorting CANH and CANL lines on my HDK board.

I am able to see the CAN bus-off error and also TEC is reached more than 128 in my case.

As you can see in above pic at TEC of 248, i got the Bus-off error.

I am attaching my project for your reference, please go through it once:

CAN_BUS_OFF_TEST_LC4357.zip

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Thanks & regards,
Jagadish.

0 Jens Benner over 1 year ago in reply to jagadish gundavarapu

Intellectual 330 points

Hello Jagadish,

I checked the Issue on to Devices. First with the procuctive Device and then on a LAUNCHXL2-TMS57012 Dev Kit. Both Devices are Equipped with a TMS570LS1224 PGE MCU but they used different CAN Transceiver. The productive board an ISO1050DUB and the Dev-Kit a SN65HVD230. With the Dev-Kit I get the CAN-Bus to Bus OFF State when schoting CAN_L and CAN_H with TEC-State 248. See logs of the ES Regsiter:

But on the productive Device the TEC-State stucks at 128:

Can this be related with the use of an isolated CAN Transceiver?

Kind regards,
Jens

0 jagadish gundavarapu over 1 year ago in reply to Jens Benner

TI__Guru 70681 points

Hi Jens,

Jens Benner said:
Can this be related with the use of an isolated CAN Transceiver?

I think you are correct; it should be due to the transceivers only. If we use same controller means the controller side should not be any difference, and it should be due to transceivers only.

And when i quickly go through the datasheets i found this:

I found that ISO1050DUB have isolation circuit inside the transceivers:

Whereas there is no isolation in the SN65HVD230 transceiver.

I am suspecting that, whenever we did short of CAN-L and CAN-H in ISO1050DUB this isolation will act and preventing the short circuit after some time, may be this is the reason the CAN Bus off is not happening on controller side.

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Thanks & regards,
Jagadish.