2008/10/2 Poul-Henning Kamp <[EMAIL PROTECTED]>: > In message <[EMAIL PROTECTED]>, "Steve > Rooke" writes: >>2008/10/2 Bruce Griffiths <[EMAIL PROTECTED]>: >> >>> Save yourself a counter and just divide the frequency down to about 1Hz >>> and time stamp the 1Hz transitions with the Linux box. >>> As long as you know the division factor its easy enough to calculate the >>> frequency. >> >>I'd planned on a simple interface to the PC via using the parallel, >>suitably strapped, as a basic output port. Now, I could use it as an >>input but I'd probably have to poll the port which would be somewhat >>inefficient [...] > > Linux should have the PPS-API from RFC2783 so that should be piece > of cake to do. > > I know that it works in FreeBSD (guess who wrote it :-) where you can > just: > cd /usr/sc/tools/test/ppsapi > make > ./ppsapitest /dev/lpt0
OK, interesting idea but I'm really not planning to use the PC to count pulses. I have a Fluke 1912A Multi Counter which can count pulses to 7 digits and I can allow that to overflow to get more digits by changing the pre-scaller I plan to use on the front end of this. It would be easier to use Linux to control an input gate to this pre-scaller with a known good period of time. Besides which, my quick scan for PPSAPI/KIT only showed patches for the 2.2 and 2.4 kernels, still I suppose I could use an older distro or even FreeBSD for that matter (it's all Unix to me). Cheers, Steve UNIX since SVR0 -- Steve Rooke - ZL3TUV & G8KVD Omnium finis imminet _______________________________________________ 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.
