50g Random Turn ON

[Joe Horn]

(12-07-2016 09:00 PM)DavidM Wrote:  ... This does imply several possibilities, though, given that others are experiencing less-than-predictable results. Some that come to mind:
- ...
- An inherent issue in the platform is making the TIMER2 interrupt processing inconsistent.

My own personal experience makes me lean more toward the last item, in that I've already had verified issues with alarms not running consistently. Since the triggering of alarms is very similar to the "timer reset", it makes sense to me that it is a good possibility.

Aha! Now I understand what you mean. Thanks for being patient and explaining it in a way that broke through my mental block. Since the 50g does have at least two known timer bugs (user alarms sometimes fail to come due for no known reason, and keystroke interrupts fail to get handled correctly when they occur at the exact moment that the busy annunciator turns off), yes, I agree with you that it is reasonable to hypothesize that the 3-day auto-turn-on sometimes might similarly fail to occur. HOWEVER, if that ever did happen, then the system real-time clock would at that moment fail to be updated. Wouldn't this cause the system clock to thereafter be off by 262144 seconds? I've seen 50g clocks drift away from the correct time, of course, but never anywhere near that much. So unless my understanding of the system real-time clock update is incorrect, then I reject the above hypothesis, and stubbornly maintain that the 50g (like the 48 & 49) NEVER misses a 262144-second auto-turn-on unless some other system interrupt occurs. Proof that I'm wrong would delight me of course, since I enjoy playing with HP calculator bugs as much as playing with HP calculator features.

I like your test method of storing something in a list instead of leaving something on the stack, so I'll try the same. I'll set up STARTOFF in some spare 50g's and 49g+'s to append TICKS to a stored list, and see what they contain after a few weeks. And see if their date/time is still close to accurate.