Hi
> On Apr 24, 2017, at 6:54 PM, Hal Murray <[email protected]> wrote: > > > [email protected] said: >> You have a “gate” from the GPSDO and a “signal” from somewhere else. If you >> want the STM to do the whole thing, the “gate” pin needs to get the job done >> in X +/- 1 cycles of the “signal” pin. Delay X (if it’s consistent) isn’t >> a problem. Having a >> +/- 1 cycle delay *is* a problem. The interrupt servicing structure in the >> MCU may or may not be able to hit things +/- 10 ns or even +/- 100 ns. >> Sometimes a “lower power” MCU with simple code is better at this than a >> multi core gizmo running a high level operating system. > > Some of the counter/timer hardware has another register where the hardware > will save a copy of the main counter when another signal happens. If your > gate time is the time between two pulses rather than the width of a single > pulse, then all the software has to do is read that copy-register before the > next pulse happens. Works a bit better if the input is edge sensing rather than level sensing …. (copy on positive edge vs keep copying the whole time the input is high) Bob > > > -- > These are my opinions. I hate spam. > > > > _______________________________________________ > time-nuts mailing list -- [email protected] > To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. _______________________________________________ time-nuts mailing list -- [email protected] To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
