CAN bus arbitration issue.

[lpcware]

Content originally posted in LPCWare by CH Wu on Thu May 07 20:24:09 MST 2015
Hello,

I would like to test the CAN bus conflict condition.
The user manual described as below. I'm confused that why the "(with the exception of the arbitration field)" is mentioned on the Bit1Error section.
What I want to know is that if there are two same ID which issue on CAN bus at same time. Is there any flag will be setted?
I would like to change the ID if the ID is hang on a arbitration situation too many times. Therefore, I need some indicator to check this kind of situation.

Bit1Error. During the transmission of a message (with the exception of
the arbitration field), the device wanted to send a HIGH/recessive level
(bit of logical value ‘1’), but the monitored bus value was
LOW/dominant.

[lpcware]

Content originally posted in LPCWare by R2D2 on Fri May 08 08:42:48 MST 2015

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Quote: CH Wu
I'm confused that why the "(with the exception of the arbitration field)" is mentioned on the Bit1Error section.

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Of course during arbitration a wrong level isn't causing an error  :O

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Quote: CH Wu
What I want to know is that if there are two same ID which issue on CAN bus at same time. Is there any flag will be setted?

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Probably you are talking about the same ID and different data  :quest:

If 2 messages with same ID and different data are transmitted at the same time (and pass arbitration) Bit errors are triggered and both transmissions are repeated until they are transmitted  :exmark:

Bit errors are no indication that the same ID is used, so a more useful approach would be a software solution:

receive this IDs and you are finding this problem before messages collide  :)