From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from pigeon.gentoo.org ([208.92.234.80] helo=lists.gentoo.org) by finch.gentoo.org with esmtp (Exim 4.60) (envelope-from ) id 1NrAxw-00074w-HW for garchives@archives.gentoo.org; Mon, 15 Mar 2010 14:08:20 +0000 Received: from pigeon.gentoo.org (localhost [127.0.0.1]) by pigeon.gentoo.org (Postfix) with SMTP id 2E52DE09A6 for ; Mon, 15 Mar 2010 14:08:20 +0000 (UTC) Received: from hrndva-omtalb.mail.rr.com (hrndva-omtalb.mail.rr.com [71.74.56.125]) by pigeon.gentoo.org (Postfix) with ESMTP id B9990E0768 for ; Mon, 15 Mar 2010 13:54:07 +0000 (UTC) X-Authority-Analysis: v=1.0 c=1 a=HJYdf0Mr3owA:10 a=8nJEP1OIZ-IA:10 a=FP58Ms26AAAA:8 a=PQ8taMwMkfZEH04bjyoA:9 a=lqfUvvWpkHNrvIlWcmwA:7 a=4QQ1fRrToR1ZZd19_LwPDyPT9IYA:4 a=wPNLvfGTeEIA:10 X-Cloudmark-Score: 0 X-Originating-IP: 71.40.157.251 Received: from [71.40.157.251] ([71.40.157.251:58661] helo=[192.168.2.37]) by hrndva-oedge03.mail.rr.com (envelope-from ) (ecelerity 2.2.2.39 r()) with ESMTP id D9/A6-01194-FFB3E9B4; Mon, 15 Mar 2010 13:54:07 +0000 Message-ID: <4B9E3F15.6090102@tampabay.rr.com> Date: Mon, 15 Mar 2010 10:07:17 -0400 From: wireless User-Agent: Mozilla/5.0 (X11; U; Linux x86_64; en-US; rv:1.8.1.23) Gecko/20100301 SeaMonkey/1.1.18 Precedence: bulk List-Post: List-Help: List-Unsubscribe: List-Subscribe: List-Id: Gentoo Linux mail X-BeenThere: gentoo-embedded@lists.gentoo.org Reply-to: gentoo-embedded@lists.gentoo.org MIME-Version: 1.0 To: gentoo-embedded@lists.gentoo.org Subject: Re: [gentoo-embedded] High Speed Serial Problem References: <20100314102459.20d7883b@osage.osagesoftware.com> In-Reply-To: <20100314102459.20d7883b@osage.osagesoftware.com> Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit X-Archives-Salt: c692c4ae-9448-45c1-a96c-01194f02f827 X-Archives-Hash: e283e3b554d193fcc1e5aa92016ef65c David Relson wrote: > I'm porting a DOS application to Linux and have encountered problems > with the high speed serial devices from which the app receives data. Well here is link to a home brewed Serial Chip buffering circuit, that may better allow you to look at the signals and protocol interactions on your serial ports. I have found the hardware ckt to help (stabalize) bit sniffing on serial communications. The keyword is 'eavesdropping' as used by embedded designers. What good about this project, is it is an easy, practical work that allows you to learn the art of eavesdropping on a com link, rs232C being the vintage form. RS485 will come much easier into enlightenment for you.... You can download the tar file from here: http://sourceforge.net/projects/serialsniffer/ If you look at the file: LinuxSPA.png (after unpacking the tar file), you'll see the circuits; I used gimp, then you can see the chips used to buffer the signals are the old reliable 1488 and 1489. I'm not sure about the max speed, I believe its around 500kbps, so you might have to find newer, faster replacements chips for the 1488 and the 1489..... When you go to test your hardware/software between the new embedded linux system and a tried and proven dos based system, this sort of buffering circuit is very valuable to keep from "loading/distorting" the signals between the 2 different devices, particularly as the speed of communications increases. You can look at both ends of the serial communications with 2 different windows on each side of the comm link, to discerning transmission issues, such as timing sync, skew etc etc. hth, James