Lpc2000

> > This happens using 29 Bit identifiers, and if the identifier of the
> > messages in the arbitration battle, have the same leading 12 bits.


Two questions:

1) Does "leading 12 bits" mean the first 12 bits transmitted? These are the 
most significant bits in the message Id right?


2) So does this mean that if there is a difference in this area, then the 
arbitration will be OK?


Some form of explantaion of how this might happen:

It is quite easy to see how this bug could happen. For Extended frames (ie. 
29-bit Id) the meddage Id is transmitted as three parts:
1) First (most significant) 11 bits.
2) SRR + IDE bits
3) Remaining 18 bits

The CAN controller likely is matching the first 11 bits and only the first 
bit of the remaining 18 bits.

This will likely break many/most J1939 or SAE11785 systems which will often 
only have differences in the last (lsb) 16 bits.