The computer only looks at the leading edge so the pulse width does not matter as long as the cable is short. look at what kind of signal is required by the serial port on the PC. Many of them will accept a TTL level 5 volt signal but you may have to level sift it to RS-232 levels (plus and minus about 9 volts) If you are driving a long cable you may have to buffer it.
Whatever you do make sure the polarity is correct. RS232 data signals use "negative logic" with 0 meaning 1 but rs232 control signls use the other convention. If you get the polarity wrong the timing is "off" by the width of the pulse. So you get a 10 uS bias. Having the PPS inverted is a common error. On Mon, May 6, 2013 at 6:38 AM, Chuck Forsberg WA7KGX N2469R <[email protected]> wrote: > I would like to set up a NTP server on a machine running Linux > (currently Korora 18). > > What are the requirements for the 1 PPS signal fed to the carrier detect > pin? > I presume the 10 us 1pps from the Thunderbolt is too narrow. > I assume the rising edge of CD is the one gpsd triggers on. > > -- > Chuck Forsberg WA7KGX [email protected] www.omen.com > Developer of Industrial ZMODEM(Tm) for Embedded Applications > Omen Technology Inc "The High Reliability Software" > 10255 NW Old Cornelius Pass Portland OR 97231 503-614-0430 > > _______________________________________________ > 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. -- Chris Albertson Redondo Beach, California _______________________________________________ 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.
