Unexplained intermittent CAN / 2CAN Jaguar problems at GSR

[Andy A.]

As another data point-

95 also had CAN bus issues at GSR, as did several other teams. We used all black jags and the serial port. It was enough of an issue that FIRST personal polled CAN teams and advised them that they couldn't say what was going on, but that it seemed like CAN wasn't always working. We elected to switch to PWM control (which also brought a half dead sidecar to our attention).

The last I had heard was that a common factor in all this was that the team was using Java as their programming language. Beyond that, there didn't seem to be any commonality. I heard some accusations of it only occurring on one driver station, or side of the field, but I can't confirm if that was true or not.

[heydowns]

1511 also saw similar failures during our time at FLR this past weekend. Fortunately for us this never manifested out on the playing field, only when testing in our pit.

I was able to attach the Windriver debugger a few times when we caught the error and have some technical details to compile and share with the developers (on my list of stuff to do hopefully today).

It appears to be almost certainly a race condition during startup whereby when the failure is tripped a task initiated for CAN handling is terminating due to following a bad pointer.

For completeness, our setup is serial/black jag based, all black jags in chain. C++ with latest (2/16) update, cRIO with image v28.