Having a few minutes where I wasn't using my RP235X I thought I would see what long term drift or inaccuracies there would be with AON. So I let it calibrate itself and just left it to run.
My simple 'sleep_ms' doesn't result in exact second intervals but that's not really problematic here, though it means the average loss per second calculation isn't entirely accurate but does show a trend -Some interesting results there. It seems LPOSC is variable and seems to be increasing its frequency as time progress which may be self-heating. I guess left long enough it will start to run fast.
The rough takeaway is it is losing about 53 ms per minute on average, about 3 seconds per hour, which is a discrepancy of less than 0.1% which really isn't that bad short-term.
But it's limited data, just one run, with voltage and temperature not changing much.
My simple 'sleep_ms' doesn't result in exact second intervals but that's not really problematic here, though it means the average loss per second calculation isn't entirely accurate but does show a trend -
Code:
.--------------------.----------.--------------.-----------.----------.-------------. | Trim Factor | AON ms | MTIME ms | Period | Slow by | Avg per sec | |-------.------------|----------|--------------|-----------|----------|-------------| | 27 | 59 0x3b | 998 | 1000.002 | 1 sec | 2 ms | 2.00 ms | | 27 | 59 0x3b | 59921 | 60006.278 | 1 min | 85 ms | 1.42 ms | | 27 | 59 0x3b | 599406 | 600064.429 | 10 mins | 658 ms | 1.10 ms | | 27 | 59 0x3b | 1198958 | 1200129.385 | 20 mins | 1171 ms | 0.98 ms | | 27 | 59 0x3b | 1798614 | 1800194.256 | 30 mins | 1580 ms | 0.88 ms | `-------^------------^----------^--------------^-----------^----------^-------------'The rough takeaway is it is losing about 53 ms per minute on average, about 3 seconds per hour, which is a discrepancy of less than 0.1% which really isn't that bad short-term.
But it's limited data, just one run, with voltage and temperature not changing much.
Statistics: Posted by hippy — Fri Nov 15, 2024 1:26 pm