Date: Tue, 22 Mar 2016 22:09:30 +0100 From: =?utf-8?Q?Peter_Ankerst=C3=A5l?= <peter@pean.org> To: Ian Lepore <ian@freebsd.org> Cc: freebsd-stable@freebsd.org, Karl Denninger <karl@denninger.net> Subject: Re: PPS input on a generic GPIO pin on Raspberry Pi. Message-ID: <13112D17-335A-4372-AEF9-ADAA2D89337E@pean.org> In-Reply-To: <EDF36350-65A9-4DB8-886E-6BCD852F2CE6@pean.org> References: <8C90C80B-AC5F-4B12-8E84-84193B8C55C4@pean.org> <56D9BDB6.6040903@denninger.net> <1457114408.13785.150.camel@freebsd.org> <EDF36350-65A9-4DB8-886E-6BCD852F2CE6@pean.org>
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[-- Attachment #1 --] > On 05 Mar 2016, at 07:54, Peter Ankerstål <peter@pean.org> wrote: >>>> >>> GPIO is supported on the Pi, I'm using it on 11-Current on my home >>> control software to drive relays on my pool hardware (e.g. valves, >>> heater, VFD motor drive, etc) and it is working very well. I don't >>> believe tapping into that at the kernel level to expose a pps signal >>> (e.g. on /dev/pps or something of the like) would be very difficult >>> at >>> all, since the low-level driver capability is already present. >>> >>> If I get some free time I'll dig around a bit and see if I can cobble >>> something up. It's of some interest to me as well since I have a GPS >>> clock here that currently talks to a serial port on an Intel-based >>> machine and being able to move that to a $35 "appliance" for NTP >>> using >>> the Adafruit setup looks sort of attractive given that the Pi plus >>> the >>> module would be under $100 all-in. >> >> Don't "cobble something up" just yet... there is "a right way" to fix >> this, which is a generic gpio-pps driver. The problem is that it >> requires support from the new INTRNG, and the rpi hasn't been converted >> to that yet. I'm checking around to see if someone has done the >> conversion for rpi and it just hasn't been reveiwed/committed yet; if >> not, I guess I'll try to do it myself. >> >> Writing the actual gpio-pps driver will be pretty quick and easy once >> we have the intrng support, I think it'll take me a couple hours. >> Any new here? Would be really nice to test this on the PI. > Oh, so there is hope. Thanks for looking into it. > > Im not a programmer myself but im willing to help if I can. > >> Also, FYI, another option with PPS is to use a usb-serial adapter and >> feed the PPS in on the CTS or DCD pin. I tested that on rpi a few >> months ago and it worked fine. There's surpisingly little jitter even >> when the usb bus is heavily loaded with other traffic such as disk or >> network IO. >> > Yes that was going to be my plan B. Good to know that it works. > > /Peter. [-- Attachment #2 --] 0 *H 01 0 + 0 *H 00ʠk} Q Y0 *H 0}1 0 UIL10U StartCom Ltd.1+0)U "Secure Digital Certificate Signing1)0'U StartCom Certification Authority0 151216010005Z 301216010005Z0u1 0 UIL10U StartCom Ltd.1)0'U StartCom Certification Authority1#0!UStartCom Class 1 Client CA0"0 *H 0 }â}[[_ u$Wy5 |̔ vnqY)\aL$dYG|B"QǤĩVD#'F k9O_]*ςz_kU.u3r #:C<ogT )K Xah8v[\KqdlO)3+u7J5";[vfL/"2ϩJ# 4ד[U TB,a˖a 7H< =q d0`0U 0 U %0++0U 0 02U +0)0'%#!http://crl.startssl.com/sfsca.crl0f+Z0X0$+0http://ocsp.startssl.com00+0$http://aia.startssl.com/certs/ca.crt0 U $l9aIF+('Hmh0 U #0N @[i04hCA0?U 80604U 0,0*+ http://www.startssl.com/policy0 *H [#'#4pnR ۡЗN⛭`]K"#H*߷Թψ;UA8 Ҟeg{ozmYE60A )wXRK6c^-Al^ k[':G=;oLv{$B5;8b,ZP4{o[-j m)[땭[4 s.c|ҴvYLJ<|ӯgu0jD2 @hl+:j\ze_ևa@HyMHINxpK?% 㤺RC:=?^&7m´) A2;E~V B1$EvcKj؝(OoپU`"$a;ҡj0$&<$ۊ+/xjzb,7}W*1ܺ tDv#8K %^P>/i?)yRuQg^z`~sP900Ϡ Fs< އ.d0 *H 0u1 0 UIL10U StartCom Ltd.1)0'U StartCom Certification Authority1#0!UStartCom Class 1 Client CA0 160126171844Z 170126171844Z0810U peter@pean.org1 0 *H peter@pean.org0"0 *H 0 ] @4JahQ |DHjk X VA[,5-7d͂?y&AIy~w5@TOW|o} .of w JL͙ ѵU*Rk/2UmF!`mnRglw-6*i #A/:Mk lj],0-5@ģu*W1|1TLEpYa ;%}Vf`굫N/IX r)ϴJөgFJ*C"K@rbdȓd]IaT wbv,h UK% i,\zGͷ#?j_9Oa0@'|)|0b_Th: <P!c Y2t^H|YX|t@m e 0~\R =VќX]C=gڝ4DgΠ{L=9bY{<m[v8d 00 U 0 U %0++0 U 0 0 U 4AfQ)` 0 U #0$l9aIF+('Hmh0o+c0a0$+0http://ocsp.startssl.com09+0-http://aia.startssl.com/certs/sca.client1.crt08U 10/0-+)'http://crl.startssl.com/sca-client1.crl0U 0peter@pean.org0#U 0http://www.startssl.com/0FU ?0=0; +70,0*+ http://www.startssl.com/policy0 *H [3N݉Y`?jȧW;s 7 Az)_ѯA5ayCoE z%(wR7j"W U5p&Fx/}'1 Y!BM=)%.DrQ̳!\qU 1{\[$R c҃N^.\"- b4 2uFs"b~FٿRϨISm A .@?6k{fZw1N0J00u1 0 UIL10U StartCom Ltd.1)0'U StartCom Certification Authority1#0!UStartCom Class 1 Client CA Fs< އ.d0 + 0 *H 1 *H 0 *H 1 160322210930Z0# *H 1xp!T<'+W90 +7100u1 0 UIL10U StartCom Ltd.1)0'U StartCom Certification Authority1#0!UStartCom Class 1 Client CA Fs< އ.d0 *H 10u1 0 UIL10U StartCom Ltd.1)0'U StartCom Certification Authority1#0!UStartCom Class 1 Client CA Fs< އ.d0 *H q <=z !P:Lm} yS_**{~)0;JOxTKۈ}+CfotrhTϤs}ESN67h&R1^[/z1n O|BQN,KIÚμijO1JcXkɗNHUlPӨz_lg[KZt=&{wh*,@~ΫRP %fS!1Q7Yc'J7]tCFp@ .4`}-a w'U[ >"l!` iHo\byBL 206Z~pl_ so?BcP~ 24U (5J|)H i8a\F (Ȼ% MeCQg.&CZ7i0%tUi}$J!`y[%1
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