TMS570LS0332: Detection of corrupted CAN signal

Sreekanth Reddy Challa

Part Number: TMS570LS0332
Other Parts Discussed in Thread: HALCOGEN

Hi,

I am using the on-chip CAN peripheral of the TMS570LS0332 for CAN communication. I am receiving a CAN signal from an external system once every 10 milliseconds. I am able to receive the CAN signal periodically in my software. I do not know how to detect the corrupted CAN signal if CAN signal is corrupted on the communication bus.

Do you have any suggestions for detecting the corrupted CAN signal?

Thanks & Best Regards,

Sreekanth challa

over 9 years ago

0 Bob Crosby over 9 years ago

TI__Guru 72500 points

Since the DCAN module will send an error frame which should generate a retransmission of a corrupted transmission, it is usually not necessary to do anything in software. However, if you want to be notified that a corrupt frame was observed, enable the DCAN status interrupt (DCAN CTL bit 2)and in the interrupt routine check the LEC (last error code) bits of the DCAN ES register. You have to respond to the interrupt quickly as the next frame will overwrite the LEC bits.

0 Bob Crosby over 9 years ago in reply to Bob Crosby

TI__Guru 72500 points

If you are using HALCoGen, take a look at this post which discusses reading the LEC code.

e2e.ti.com/.../2057892

0 Sreekanth Reddy Challa over 8 years ago in reply to Bob Crosby

Expert 1320 points

Hi Bob Crosby,

Thanks for your support.

Best regards,
Sreekanth challa

0 Sreekanth Reddy Challa over 8 years ago in reply to Bob Crosby

Expert 1320 points

Hi Bob Crosby,

I have one more query regarding DCAN CRC. I have configured DCAN periphral such that the interrupt gets triggerd every time i recevie a new CAN message with the specified CAN ID and of specified datalength.

I did not configure the interrupt on Status Change. In this case, do i get the interrupt if i receive the CAN data with the configured ID and data length but wrong CRC.

Thanks & Best regards,
Sreekanth challa

0 Bob Crosby over 8 years ago in reply to Sreekanth Reddy Challa

TI__Guru 72500 points

No, all CAN nodes on the bus verify the CRC as the message comes in. Any node that computes a CRC error will force an error condition on the bus causing all nodes to discard the message. The sender of the message will then attempt to retransmit the message. Therefore, no message with a CRC error will ever be store in a mailbox. You can only get an interrupt from a message with CRC error if you enable interrupts on status change.

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0 Sreekanth Reddy Challa over 8 years ago in reply to Bob Crosby

Expert 1320 points

Hi Bob Crosby,

Thanks for your support.

Best regards,
Sreekanth

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TMS570LS0332: Detection of corrupted CAN signal