Stuart Henderson:
> > I don't have any practical experience with nmea(4), but I'd like
> > to draw attention to ldattach(8)'s -t option. Unless your receiver
> > offers a pulse per second signal, you are limited to a very jittery
> > timestamp from the serial telegram, mirroring udcf's fundamental
> > problem.
>
> The problem isn't getting the pulses generated, it's getting
> them hooked up to the computer and figuring out accurately
> when they occurred.
That's why I mentioned ldattach -t. We can timestamp on DCD or CTS
transitions. On a real serial port, those will trigger an interrupt.
That shouldn't be too bad.
I see that we also have code for timestamping on ucom(4), but since
USB devices cannot directly generate interrupts and are in fact
polled by the host controller, that will give poor results.
--
Christian "naddy" Weisgerber naddy@mips.inka.de
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