chris <chris-nos...@tridac.net> wrote: > On 06/16/22 16:20, Jim Pennino wrote: >> Thibaut HUMBERT<planet...@gmail.com> wrote: >>> Le jeudi 16 juin 2022 à 16:37:33 UTC+2, David Taylor a écrit : >>>> On 16/06/2022 10:00, Thiebaud HUMBERT wrote: >>>>> To do the inversion, I just changed the "Pulse Mode" parameter to >>>>> "Falling edge" from "Rising edge". >>>>> The offset induced by the "pulse length" has disappeared. >>>>> But there is still an offset of around 10.3ms, which I think is induced >>>>> by USB as explained in this article about other chipsets >>>>> (https://lists.freebsd.org/pipermail/freebsd-usb/2019- August/016078.html) >>>> Yes, Thiebaud, USB is not good enough for PPS signals! >>>> >>>> See if your motherboard has a true serial port - perhaps just as a header >>>> but >>>> not a back connector. If not, just set the offset of the PPS to ~10.3 >>>> milliseconds (10.3 - IIRC the offsets are in milliseconds but please >>>> check). >>>> Plus or minus 10.3, try it and see! Not perfect, but better than nothing. >>>> >>>> You might find better results using that GPS/PPS with a Raspberry Pi as a >>>> stratum-1 server and offering that as a server on your LAN. >>>> >>>> Cheers, >>>> David >>>> -- >>>> Cheers, >>>> David >>>> Web: http://www.satsignal.eu >>> >>> >>> I have a serial port, but I don't know how to convert the PPS output (0 / >>> 3.3V) to RS232 (-5V / +5V). >> >> You go to amazon.com and search for "level converter 3.3 to 5". >> >> > > You need a ttl to rs232 converter.
That is what a level converter 3.3 to 5 is. The RS-232 standard mark is +3 to +15 V and space is -15 to -3 V, which means a 0/3v level converter to -5/+5V meets the RS-232 standard. -- This is questions@lists.ntp.org Subscribe: questions+subscr...@lists.ntp.org Unsubscribe: questions+unsubscr...@lists.ntp.org
