Date: Mon, 23 Jul 2018 11:40:17 +0200 From: Per olof Ljungmark <peo@nethead.se> To: David Cornejo <dave@dogwood.com> Cc: db@db.net, freebsd-arm <freebsd-arm@freebsd.org> Subject: Re: rpi3 and Adafruit GPS Hat Message-ID: <7a14173c-cc28-6dc7-3787-a5b77a396b30@nethead.se> In-Reply-To: <CAFnjQbt395y4xyHEp52GAHW9X9bHvdCAT9q-gKA2--RvQvqTtA@mail.gmail.com> References: <47f49a55-66b0-1c02-4530-4701a3bd0c43@nethead.se> <20180718170157.GA40221@night.db.net> <ba31ee27-1d17-8616-96b2-b982268f0dc2@nethead.se> <CAFnjQbt395y4xyHEp52GAHW9X9bHvdCAT9q-gKA2--RvQvqTtA@mail.gmail.com>
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On 07/23/18 10:46, David Cornejo wrote: > this might be a little blasphemous, but for grins I tried an Oncore with > PPS to a GPIO and running the serial through a TTL-USB serial cable and > that seems to work ok. > > there's probably some good reason that this is a bad idea. Depends on what precision you are after, but for lowest possible jitter you need to use the uart, the difference is in magnitudes. > On Sun, Jul 22, 2018 at 9:09 PM Per olof Ljungmark <peo@nethead.se > <mailto:peo@nethead.se>> wrote: > > On 07/18/18 19:01, Diane Bruce wrote: > > On Wed, Jul 18, 2018 at 05:10:16PM +0200, Per olof Ljungmark wrote: > >> Being a complete newbie to arm I thought a nice project would be to > >> build a NTP server with the parts in the subject line. > >> > >> Unfortunately I have almost no idea where to start, it seems > FreeBSD for > >> arm have shifted around quite a bit, almost none of the googled > pages I > >> find has relevance, and to add insult to injury, the Pi project > >> apparently shifted the serial ports around for the Pi3. > >> > >> What I need to achieve, > >> > >> - Stop the kernel to use the uart for console output (I have ethernet > >> and HDMI connected) > > > > No need. > > > > change your config.txt > > > > #dtoverlay=pi3-disable-bt > > device_tree_address=0x4000 > > kernel=u-boot.bin > > enable_uart=1 > > > > This moves the console port to the less capable micro uart port > > this will free up the good uart (the pl011 device) as /dev/ttyu0 > > > > Remove the pi3-disable-dt in config.txt > > enable_uart=1 is needed. > > > >> VERY grateful if someone that knows better can give me a push in the > >> right direction for up to date information. > > .. > > > > This is assuming you use FreeBSD-12 (Head of tree) > > > > Yes, 12.0-CURRENT #2 r336461. > > Unfortunately your advice did not solve the problem, when the hat is > attached it sends NMEA sequences to the u-boot loader making it > impossible to boot further, just like it is described in this thread: > > http://freebsd.1045724.x6.nabble.com/Adding-a-GPS-Module-hat-shield-on-a-Raspberry-Pi-td6236680.html > > > _______________________________________________ > freebsd-arm@freebsd.org <mailto:freebsd-arm@freebsd.org> mailing list > https://lists.freebsd.org/mailman/listinfo/freebsd-arm > To unsubscribe, send any mail to > "freebsd-arm-unsubscribe@freebsd.org > <mailto:freebsd-arm-unsubscribe@freebsd.org>" > > > > -- > Kailua, Hawaiʻi > US +1 (808) 728-3050 > UK +44 (020) 3286 2808 >
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