From mboxrd@z Thu Jan 1 00:00:00 1970 X-Spam-Checker-Version: SpamAssassin 3.4.4 (2020-01-24) on polar.synack.me X-Spam-Level: X-Spam-Status: No, score=-1.9 required=5.0 tests=BAYES_00,FREEMAIL_FROM autolearn=unavailable autolearn_force=no version=3.4.4 X-Received: by 10.42.53.80 with SMTP id m16mr16552355icg.26.1424776305715; Tue, 24 Feb 2015 03:11:45 -0800 (PST) X-Received: by 10.140.20.247 with SMTP id 110mr165732qgj.17.1424776305683; Tue, 24 Feb 2015 03:11:45 -0800 (PST) Path: border2.nntp.dca1.giganews.com!nntp.giganews.com!hl2no27152250igb.0!news-out.google.com!n6ni11qar.0!nntp.google.com!j7no5459448qaq.1!postnews.google.com!glegroupsg2000goo.googlegroups.com!not-for-mail Newsgroups: comp.lang.ada Date: Tue, 24 Feb 2015 03:11:45 -0800 (PST) In-Reply-To: Complaints-To: groups-abuse@google.com Injection-Info: glegroupsg2000goo.googlegroups.com; posting-host=105.210.0.209; posting-account=orbgeAkAAADzWCTlruxuX_Ts4lIq8C5J NNTP-Posting-Host: 105.210.0.209 References: <8e30f54c-81c4-4861-897c-bb6c563c76e8@googlegroups.com> User-Agent: G2/1.0 MIME-Version: 1.0 Message-ID: Subject: Re: silly ravenscar question From: jan.de.kruyf@gmail.com Injection-Date: Tue, 24 Feb 2015 11:11:45 +0000 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: quoted-printable Xref: number.nntp.giganews.com comp.lang.ada:192312 Date: 2015-02-24T03:11:45-08:00 List-Id: On Tuesday, February 24, 2015 at 12:29:02 PM UTC+2, Dmitry A. Kazakov wrote= : > On Tue, 24 Feb 2015 01:07:31 -0800 (PST), jan.de.kruyf wrote: >=20 > > I am busy doing a very light ethernet fieldbus for a few Olimex stm34 b= oards and a pc. >=20 > You mean the boards will be sort of terminals. And the master will be? > Which cycles you are talking about, 1ms, 0.1ms, 0.01ms? Pc, havn't dug into that part yet. I was going to use Proview scada/plc wit= h powerlink, but there is a sizable custom section in my code. So its 'to b= e decided' at the moment. I am aiming for 1 msec cycletime, but if it comes out at 2 I will also be h= appy. Remember STM runs only at 168 Mhz.=20 >=20 > EtherCAT does not need special hardware. If you mean Beckhoff's piggyback= , > you don't have to use it. You can do all it does with a plain board and r= aw > Ethernet. Admittedly it would be a lot of work and EtherCAT slave protoco= l > (all upper levels) is a horrific mess. >=20 yes I know, but then the timing advantage is virtually gone. And you are ve= ry right about the mess. I sorted a Beckhoff installation with comms issues= a few years back. I was on the phone to Germany daily, but I got send aro= und in circles. From this supplier to that one to that one. . . . So in the end -I- sorted it. Help from any of them was well below standard.= =20 > > Is there any interest in the community? I am willing to put it under GP= L. >=20 > If that would not hinder selling the terminals to the end customers witho= ut > exposing the sources... You raise an interesting point. Do I give things away then for everybody to= get rich with? . . .=20 >=20 > All existing fieldbuses are extremely poor designed, in my view. But I > doubt it would be a work for one man. [Begriffe, welche sich bei der Ordnung der Dinge als n=FCtzlich erwiesen ha= ben, erlangen =FCber uns leicht eine solche Autorit=E4t, dass wir ihres ird= ischen Ursprungs vergessen und sie als unab=E4nderliche Gegebenheiten hinne= hmen.] from: http://en.wikiquote.org/wiki/Albert_Einstein So it took me a week of sweating to get to the depth of that truth, but now= it looks rather doable. So, did you work at all with the gnat ravenscar package for STM, Dimitry? cheers. j.