I don't think it's that simple, Kent. I do not recall having any realtime delays or errors when I was using a USB microscope camera on a D510MO with LinuxCNC. My experience may not be of much value, though, as I was using a 7I43 with hardware step generation, so I only had a servo thread.
For people needing to use USB devices with LinuxCNC, an FPGA device like 7I43 or 5I25 would be a good $80 investment to eliminate the base thread. -- Ralph ________________________________________ From: Kent A. Reed [kentallanr...@gmail.com] Sent: Tuesday, July 24, 2012 4:08 AM To: Enhanced Machine Controller (EMC) Subject: [Emc-users] USB badness, was Re: BASE_PERIOD and Intel D525MW boards On 7/24/2012 5:55 AM, andy pugh wrote: > On 24 July 2012 03:09, John Stewart <alex.stew...@crc.ca> wrote: >> I've got a D525mw, and every once in a while it'll throw up an RTAI error. > I found that my D510 was very reliable for latency unless I had the > webcam plugged in. > There doesn't seem to be any pattern emerging yet as to which USB devices cause problems and which do not. For want of a better explanation, I've assumed some USB devices upset realtime performance because their drivers enable DMA activity. If this hypothesis were true, then devices requiring fast service of large data blocks likely would be bad choices. Without more explicit guidelines, my approach has been to avoid USB connections like the plague. Any thoughts? Regards, Kent ------------------------------------------------------------------------------ Live Security Virtual Conference Exclusive live event will cover all the ways today's security and threat landscape has changed and how IT managers can respond. Discussions will include endpoint security, mobile security and the latest in malware threats. http://www.accelacomm.com/jaw/sfrnl04242012/114/50122263/ _______________________________________________ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
