In article <jgg8pb$diq$1...@dont-email.me>, david- tay...@blueyonder.co.uk.invalid says... > > > The generic BSD kernel does not enable PPS support by default. You must > > recompile to enable PPS. > > > > > > The page you quoted says the following in the section "System software > > customization" (about 45% down the page in the Software section): > > > > System software customisation > > > > Need to add one line to the Kernel configuration: > > > > options PPS_SYNC > > > > and recompile the Kernel. On my 133MHz/48MB system this can take > > several hours. Note the configuration suggestions below before you > > recompile the kernel. > > But that was FreeBSD 5.4 and some six years ago. Note that I did not make > the same remark about FreeBSD 8 - so whether that does or does not need > recompiling is something I don't currently know. > > Cheers, > David
I did FreeBSD 8.1 with that and it was ok, and I've done FreeBSD 9.0 recently. Main advantage for me is kernel discipline narrows down in a few minutes, instead of a few hours. Can get a 5-10 uS spike with aircon/heater, but otherwise it'll drift around 0-2 uS. Advice for those going for microsecond accuracy: Find the 14.318 crystal, and see if you can cover it in polystyrene. Takes the drift from 10 to 2 us because air can no longer reach it, only the PCB temp, and that has more thermal mass/slower time constant. Rhys. _______________________________________________ questions mailing list questions@lists.ntp.org http://lists.ntp.org/listinfo/questions
