• Q1: What is the counter frequency? (presumeably 32Khz)

    Yes, 32kHz

    Q2: The datasheet indicates two external crystals, but the schematic shows none.

    The MDBT42 module has a crystal in it. Just a high speed (8MHz?) one though, no low speed (32kHz) one - that is just an on-chip RC oscillator calibrated by the high speed one.

    Q:3 L14 indicates on an up that rtc.tStop should occur. After the clear, shouldn't the clock stop and therefore no additional counting?

    It should, yes. However it appears not to be working for some reason.

    Calling poke32(rtc.tStop,1) does stop the RTC though.

    Q4: 163822 What is this value? (total counter edges?)

    Yes. Clock runs at 32kHz, you're checking every 5 seconds. It's basically 32768*5

  • Thr 2020.03.05

    Thank you @Gordon for taking the time to respond promptly.

    re: 'Q:3 L14 indicates on an up that rtc.tStop should occur'

    'It should, yes. However it appears not to be working for some reason'

    From your detailed explanation, I believe I now have enough to push on. I have a bunch of time this weekend to dive into the examples, and with a few other trial attempts, may be able to get to the bottom of that example.

    re: 'Calling poke32(rtc.tStop,1)'

    On the drive into work this morning, had the exact thought, (before your post #2 arrived) but hadn't the time last evening to test. In any event, I should have the ammo to get the task I am after, done.

    re: 'It's basically 32768*5'

    Geez, do I feel like a Dolt! I even had that detail (in words) nicely spelled out beneath question #4! Amazing how I was so immersed in, and convinced that, the issue was with how the crystals (or lack of) controlled the timing at an underlying level, causing me to ponder why 163 822 wasn't smaller than 32 000, but not stepping back and looking from the 10,000ft level to view the interval duration and the run time effect with time.

    Thanks for the insight and now afford you the time back to Bangleland.
    or maybe it was a nice break taking a bit of a sidestep . . .


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