From owner-freebsd-arm@freebsd.org Mon Jul 23 15:32:44 2018 Return-Path: Delivered-To: freebsd-arm@mailman.ysv.freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2610:1c1:1:606c::19:1]) by mailman.ysv.freebsd.org (Postfix) with ESMTP id F18C9104DFA8 for ; Mon, 23 Jul 2018 15:32:43 +0000 (UTC) (envelope-from ralph@ralphsmith.org) Received: from ralphsmith.org (ralphsmith.org [98.172.20.124]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (Client CN "ralphsmith.org", Issuer "Go Daddy Secure Certificate Authority - G2" (verified OK)) by mx1.freebsd.org (Postfix) with ESMTPS id 9226B81820 for ; Mon, 23 Jul 2018 15:32:43 +0000 (UTC) (envelope-from ralph@ralphsmith.org) Received: from [192.168.140.100] ([198.99.129.142]) (authenticated bits=0) by ralphsmith.org (8.15.2/8.15.2) with ESMTPSA id w6NFBJce045715 (version=TLSv1.2 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=NO); Mon, 23 Jul 2018 11:11:22 -0400 (EDT) (envelope-from ralph@ralphsmith.org) DKIM-Signature: v=1; a=rsa-sha256; c=simple/simple; d=ralphsmith.org; s=201502; t=1532358683; bh=F6GoTHR8fiIzh6ls8oQi0Jzup25J7WsW44iiq2IPoWI=; h=Subject:From:In-Reply-To:Date:Cc:References:To; b=uBZhS+gftmP4G+WvgU5Jc/qjQ+emQ9F6ozci/qo7nmxVAbAE4uRLrxPbqB3C9FUt5 NkiKL28vf96ITwUAQj4B4r3uDb5muY0j5xQasDlW4sdF6HsEpX9gIdFv4zD81aD2tu oUO7OIKlHPJONwjwvbbmYY6l6SRVb9QWGpBb/M5A= Content-Type: text/plain; charset=utf-8 Mime-Version: 1.0 (1.0) Subject: Re: rpi3 and Adafruit GPS Hat From: Ralph Smith X-Mailer: iPhone Mail (15F79) In-Reply-To: <7a14173c-cc28-6dc7-3787-a5b77a396b30@nethead.se> Date: Mon, 23 Jul 2018 11:11:12 -0400 Cc: David Cornejo , freebsd-arm Content-Transfer-Encoding: quoted-printable Message-Id: <72A10F81-7BC3-4B4F-BDC0-26A47DB04ABD@ralphsmith.org> References: <47f49a55-66b0-1c02-4530-4701a3bd0c43@nethead.se> <20180718170157.GA40221@night.db.net> <7a14173c-cc28-6dc7-3787-a5b77a396b30@nethead.se> To: Per olof Ljungmark X-BeenThere: freebsd-arm@freebsd.org X-Mailman-Version: 2.1.27 Precedence: list List-Id: "Porting FreeBSD to ARM processors." List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Mon, 23 Jul 2018 15:32:44 -0000 Sent from my iPhone >> On Jul 23, 2018, at 5:40 AM, Per olof Ljungmark wrote: >>=20 >> 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. >>=20 >> there's probably some good reason that this is a bad idea. >=20 > Depends on what precision you are after, but for lowest possible jitter > you need to use the uart, the difference is in magnitudes. But he=E2=80=99s not running the PPS through the USB serial port, it is goin= g directly to GPIO. Correct me if I=E2=80=99m wrong here, but once ntpd lock= s to the PPS there is no real difference between the two. I=E2=80=99m runnin= g that exact scenario here with two Pis, both Model 2. One has an Adafruit G= PS HAT directly attached, and the other has the GPS connected to a USB-TTL s= erial adapter, with the PPS connected to the GPIO. Both sync to PPS with the= offset typically around 4 =CE=BCs and jitter around 2 =CE=BCs. I may try it= with an Oncore I have on hand but that will have to wait a month or so for o= ther things to settle down.=20 Ralph >> On Sun, Jul 22, 2018 at 9:09 PM Per olof Ljungmark > > wrote: >>=20 >>>> 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. >>>>=20 >>>> 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. >>>>=20 >>>> What I need to achieve, >>>>=20 >>>> - Stop the kernel to use the uart for console output (I have ethernet >>>> and HDMI connected) >>>=20 >>> No need. >>>=20 >>> change your config.txt >>>=20 >>> #dtoverlay=3Dpi3-disable-bt >>> device_tree_address=3D0x4000 >>> kernel=3Du-boot.bin >>> enable_uart=3D1 >>>=20 >>> 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 >>>=20 >>> Remove the pi3-disable-dt in config.txt >>> enable_uart=3D1 is needed. >>>=20 >>>> VERY grateful if someone that knows better can give me a push in the >>>> right direction for up to date information. >>> .. >>>=20 >>> This is assuming you use FreeBSD-12 (Head of tree) >>=20 >> Yes, 12.0-CURRENT #2 r336461. >>=20 >> 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: >>=20 >> http://freebsd.1045724.x6.nabble.com/Adding-a-GPS-Module-hat-shield-on= -a-Raspberry-Pi-td6236680.html >>=20 >>=20 >> _______________________________________________ >> 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 >> " >>=20 >>=20 >>=20 >> --=20 >> Kailua, Hawai=CA=BBi >> US +1 (808) 728-3050 >> UK +44 (020) 3286 2808 > _______________________________________________ > 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"