dginsb...@gmail.com said: > First, the frequency offset of the microcontroller. I use a built-in > counting timer in the uC which runs at 84MHz to measure the duration between > 2 PPS. What I get is ~84008000 timer ticks between two pulses, which > corresponds to about 95ppm offset. While the crystal on the board is of the > cheapest variety, I think 95ppm is just too much. Is that correct, and 95ppm > offset even for a the most crappy oscillator is not a reasonable value?
It isn't totally unreasonable. Yes, 95 PPM is the high end of even cheap crystals, but it could easily be a design error. The capacitive loading of the circuit might not match the specs on the crystal. There is also the possibility of a software bug. OSes have a long history of not getting that quite right. They are usually close enough so that nobody cares unless some geek starts monitoring the details. -- These are my opinions. I hate spam. _______________________________________________ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
