Given the age of these units, RAM space was probably at a premium and the routine in the firmware that converts from GPS time to human readable time is overflowing a variable. Perhaps an undiscovered bug or a limitation that the programmers didn't figure would matter this far down the road.
On Tue, Sep 1, 2015 at 11:36 AM, Jonathan Peakall <[email protected]> wrote: > Thanks for the thoughts. I am going to program up a data dump from the > unit and see if I can find anything. For the moment I have simply corrected > the UTC offset manually, which means reprogramming twice a year. So odd, > over a decade of use with no problems. I checked my DST code and it is > correct, the date is the issue. ANother odd aspect: The date is > incrementing every day. It was starting with 1/14/2000 now it says > 1/16/2000. Hmmm... > > Jonathan > > > > > > > On 8/31/2015 12:27 AM, Paolo Cravero wrote: > > [not a solution, but info worth sharing] > > Hi Jonathan, > when I read your description my thoughts went back to that time my Garmin > Geko 201 (small GPS tracker) recorded a date 15 years back in time. > > Digging around I discovered that GPS/NMEA carry a 10 bit "week" > information, which makes a rollover every 1024 weeks. But quoting a search > result (written in 2013): > > The last rollover (and the first since GPS went live in 1980) > was 0000 22 August 1999; the next would fall in 2019, but plans are > afoot to upgrade the satellite counters to 13 bits; this will delay > the next rollover until 2173 > > So what you are seeing is not due to a week rollover, even though my Geko > 201 showed the problem in 2010 (and others too). > > Perhaps Motorola hardcoded a "starting date" that matched a week number > and counted from that point. Then a software variable has overflowed or > 1024 have passed and you're back to "Oncore UT day 0". > > If the delta_days is constant you might add it to your code right after > reading the date information? You might discover is it some integer number > falling within powers of 2. :-) > > Paolo > > PS: Garmin has issued a firmware update for the Geko 201. But I doubt I > will get a new firmware in 2019... > > -- > You received this message because you are subscribed to the Google Groups > "neonixie-l" group. > To unsubscribe from this group and stop receiving emails from it, send an > email to [email protected]. > To post to this group, send email to [email protected]. > To view this discussion on the web, visit > https://groups.google.com/d/msgid/neonixie-l/CABj2Vab8pYOcfn9ttwxtRx7%2BX-Egrhdt_7ns%2Bw6%3D1UsWGJumEw%40mail.gmail.com > <https://groups.google.com/d/msgid/neonixie-l/CABj2Vab8pYOcfn9ttwxtRx7%2BX-Egrhdt_7ns%2Bw6%3D1UsWGJumEw%40mail.gmail.com?utm_medium=email&utm_source=footer> > . > For more options, visit https://groups.google.com/d/optout. > > > -- > You received this message because you are subscribed to the Google Groups > "neonixie-l" group. > To unsubscribe from this group and stop receiving emails from it, send an > email to [email protected]. > To post to this group, send email to [email protected]. > To view this discussion on the web, visit > https://groups.google.com/d/msgid/neonixie-l/55E5C5E2.8090105%40madlabs.info > <https://groups.google.com/d/msgid/neonixie-l/55E5C5E2.8090105%40madlabs.info?utm_medium=email&utm_source=footer> > . > > For more options, visit https://groups.google.com/d/optout. > -- You received this message because you are subscribed to the Google Groups "neonixie-l" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. To post to this group, send an email to [email protected]. To view this discussion on the web, visit https://groups.google.com/d/msgid/neonixie-l/CAM1F4kRX8SJRXtoi0KYkGLcRjNBFvtZ6X%2BsAcLzmstoYQ2OQTg%40mail.gmail.com. For more options, visit https://groups.google.com/d/optout.
