From mboxrd@z Thu Jan 1 00:00:00 1970 Message-ID: <485F5ABB.8080007@domain.hid> Date: Mon, 23 Jun 2008 10:11:39 +0200 From: Anders Blomdell MIME-Version: 1.0 References: <485E48A0.6050706@domain.hid> <200806230031.32512.berlemont.hauw@domain.hid> In-Reply-To: <200806230031.32512.berlemont.hauw@domain.hid> Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Subject: Re: [Xenomai-help] DAQ SYSTEM COMPATIBILITY List-Id: Help regarding installation and common use of Xenomai List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Alexis Berlemont Cc: xenomai@xenomai.org Alexis Berlemont wrote: > Hi, > >> i need to buy an USB DAQ system and use it with Xenomai. I have an eye >> on the National Instruments USB 6218 which is provided with linux drivers. >> How can we now if an hardware will be usable with Xenomai ? >> Do we need >> the driver sources in order to be able to rewrite it for real time >> purposes ? > > A nice way would be to recover the Linux driver and make it work with Comedi > (which is a kind of framework for acquisition drivers, an RTDM port is > available). > > Do you have the driver sources ? Just to see how it works... > > To fully comply with real-time constraints, maybe usb20rt might be > necessary... Another thing to keep in mind when using USB, is that USB microframes/frames are only sent each 125 us/1 ms which gives a limit to how fast a control loop can possibly be closed over USB (8kHz/1kHz, which is way below what can achieved with USB if only data acquisition is needed). Best regards Anders Blomdell -- Anders Blomdell Email: anders.blomdell@domain.hid Department of Automatic Control Lund University Phone: +46 46 222 4625 P.O. Box 118 Fax: +46 46 138118 SE-221 00 Lund, Sweden