From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from europa.AD.HartBrothers.Com (unknown [50.46.86.110]) by huchra.bufferbloat.net (Postfix) with ESMTP id 7A2452012AC for ; Wed, 9 May 2012 15:02:53 -0700 (PDT) Received: from mail-bk0-f43.google.com ([209.85.214.43]) by europa.AD.HartBrothers.Com over TLS secured channel with Microsoft SMTPSVC(6.0.3790.4675); Wed, 9 May 2012 22:02:52 +0000 Received: by bkty5 with SMTP id y5so1574116bkt.16 for ; Wed, 09 May 2012 15:02:49 -0700 (PDT) Received: by 10.204.153.6 with SMTP id i6mr638588bkw.114.1336600969880; Wed, 09 May 2012 15:02:49 -0700 (PDT) MIME-Version: 1.0 Received: by 10.205.142.146 with HTTP; Wed, 9 May 2012 15:02:28 -0700 (PDT) In-Reply-To: <20120509213841.GB4379@thyrsus.com> References: <02af01cd2daf$05b24bb0$1116e310$@navisys.com.tw> <20120509203719.GA3855@thyrsus.com> <4FAADF21.6030907@techstarship.com> <20120509213841.GB4379@thyrsus.com> From: Dave Hart Date: Wed, 9 May 2012 22:02:28 +0000 Message-ID: To: esr@thyrsus.com Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: quoted-printable X-OriginalArrivalTime: 09 May 2012 22:02:52.0959 (UTC) FILETIME=[7B3DA2F0:01CD2E2F] Cc: thumbgps-devel@lists.bufferbloat.net Subject: Re: [Thumbgps-devel] Article -- Macx-1: GPS receiver with standard USB connector and PPS support X-BeenThere: thumbgps-devel@lists.bufferbloat.net X-Mailman-Version: 2.1.13 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Wed, 09 May 2012 22:02:53 -0000 On Wed, May 9, 2012 at 9:38 PM, Eric S. Raymond wrote: >> =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 = =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 Also, >> are there other applications which expect the pps to be coming >> though another handshaking pin besides DCD? > > Note that GPSD will actually notice PPS over RI and CTS as well. > It doesn't care - a transition on any handshake line is treated > as a PPS event, because the onlty thing it ever means from a GPS. While I appreciate GPSD's flexibility, I advise against exercising it needlessly. All of the PPSAPI implementations which support serial port control line input that I'm aware of want to see it on the carrier detect line. If you know you'll only ever care about using the hardware with GPSD, any control line will do for PPS, but to use it directly with ntpd, the PPSAPI implementations dictate using the DCD line. I had a vague recollection GPSD could use PPSAPI where it's available. If that's true, when GPSD is using PPSAPI, isn't it restricted to using carrier detect in practice? Cheers, Dave hart