cogoman wrote: > > I don't know how many IOs the Beagle board has, but if it has enough, > this could get interesting. I have an old Dell Optiplex GXa, and the fastest > I can run a thread safely on it is about 50uS. Using a quadrature interface > to drive stepper motors it's good for rapids of 300 inch per minute at > .00025" per step (if my calculations are correct). That's faster than most > stepper motors can charge/discharge. If the Beagle board can run 50 to 100 > times faster than that, the actual stepper motor controller might be > implemented mostly in software. Hmmmm. > All of this is theoretical at the moment. The Beagle brings out enough I/O to equal a PC parallel port, but not much more. 50 to 100 times faster? No way that's going to happen without external hardware.
What I am looking at is the time it takes to send commands out the parallel port in consecutive instructions, that has nothing to do with the dispatch rate of a R-T thread. I suspect the Beagle may be able to run threads a bit faster than mid-range PCs, but it is only a 500-600 MHz CPU, so I doubt it will handle much better than 25us threads. We don't have RTAI running on it yet, although there is a port of rt-Linux available. Since we use RTAI by default, and nobody seems to know if the rt-Linux interface to EMC2 even works anymore, I'd rather stick with RTAI. The idea here is to keep the GUI on another PC, some people want to use laptops. Without the fairly heavy load of the GUI and its preview window, what is left of EMC2 shouldn't use up too much of the CPU. I'm much more interested in servo interfaces, but I think the stuff I'm working on should also work for software stepper output. Jon ------------------------------------------------------------------------------ Come build with us! The BlackBerry(R) Developer Conference in SF, CA is the only developer event you need to attend this year. Jumpstart your developing skills, take BlackBerry mobile applications to market and stay ahead of the curve. Join us from November 9 - 12, 2009. Register now! http://p.sf.net/sfu/devconference _______________________________________________ Emc-users mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/emc-users
