Date: Fri, 1 Feb 2013 20:04:35 +0100 From: Bernd Walter <ticso@cicely7.cicely.de> To: Ian Lepore <ian@freebsd.org> Cc: freebsd-arm@freebsd.org Subject: Re: SD card -image- for the beaglebone Message-ID: <20130201190434.GK67562@cicely7.cicely.de> In-Reply-To: <1359668656.93359.339.camel@revolution.hippie.lan> References: <510A4F5B.7000407@g7iii.net> <1359646574.93359.327.camel@revolution.hippie.lan> <510AE1D6.8010203@g7iii.net> <1359668656.93359.339.camel@revolution.hippie.lan>
next in thread | previous in thread | raw e-mail | index | archive | help
On Thu, Jan 31, 2013 at 02:44:16PM -0700, Ian Lepore wrote: > On Thu, 2013-01-31 at 21:27 +0000, Iain Young wrote: > > On 31/01/13 15:36, Ian Lepore wrote: > > > > > So you're interested in a PPS driver for BeagleBone? That would be fun > > > to play with, I wonder what the BB's timer hardware looks like? It'd be > > > easy enough to do with a gpio interrupt I suspect, but the timing geek > > > in me can't resist going for the nanosecond-accurate measurements when > > > possible, even if it is kind of pointless for millisecond-accurate NTP. > > > > Yep. Planning on hooking up MSF, DCF, and TDF clocks to GPIO pins, as > > well as some GPS units. Originally planned for doing this with some > > Pi, but found the bone had serial ports and things developed from there > > > > Planning on abusing UART3's CTS pin for initial basic testing, as > > radioclkd and radioclkd2 have only support for serial ports, but > > then it will be working out what if anything I need to patch into the > > kernel to get the PPS subsystem to listen to particular GPIO pins. > > > > Also planning to test PHK's ntpns, which has DCF support, > > and should be easy to modify for MSF. Anyway, this is heading far > > too quickly to being on-topic for time-nuts but off-topic here > > You might be surprised how many time nuts read this list, several of us > do it for a living. Absolutely - there is a reason why I have a rubidium here. Thought of using it with a zedboard - it's FPGA and gbit/s ethernet sounds as a good combination. The most important thing however is a red LED based 7-Segment microsecond display (without multiplexing) - not that anyone can read. I even thought of doing ntp protocol in FPGA logic. Unfortunately the GPS receiver I bought has no PPS output :-( Getting an accurate time is more difficult then keeping it. And leap seconds won't make it easier. What are MSF and TDF? I'm aware of GPS, DCF77 and LORAN-C to be available in Germany. -- B.Walter <bernd@bwct.de> http://www.bwct.de Modbus/TCP Ethernet I/O Baugruppen, ARM basierte FreeBSD Rechner uvm.
Want to link to this message? Use this URL: <https://mail-archive.FreeBSD.org/cgi/mid.cgi?20130201190434.GK67562>