Thursday, May 6, 2010

Oh yeah, about the plane

I flew from Livermore, CA (KLVK), to Gwinnett county-briscoe field (KLZU) last week. It took about 14 hours or so, I had amazing tail winds the first day, I was seeing ground speeds 190KTS or more, even hitting 200+ at one point.

The EM had a strange problem in that it would basically stop working after one gallon (or when the counter hit 32768). I 'sorta' fixed it that night by putting in a watchdog timer, but that was only a band-aid. The real problem was some more signed/unsigned problems with the internal counters and some of the math.

Once the value hit 32768, it would 'go negative', and a bit shift would shift in a 0xffff causing a cascade of nonsense values. It caused it to hang before I put in the watch dog.

Now that is all fixed. There is still an occasional crash on the app side, and sometimes my windows machine simply hangs, or 'stalls' for long periods of time. If I can move to an embedded linux or other CF card friendly OS, I'm hoping I won't have that problem.

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