-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA1 On 2/1/2013 3:15 PM, Gregory Perry wrote: >> The 100 mS 'hiccup' comes into play for anything running on Linux >> (which is running on the ARM core) if you don't have help from >> something like Xenomai or PREEMPT_RT. > > I understand all of those issues, I've been working on getting > Xenomai integrated with the BeagleBone for a few months now for > hard realtime GPIO capability on an unrelated project to CNC. A > few miserable months I should say. > >> You absolutely could use Python to feed gcode to the PRU, but >> then you need to implement most everything that is LinuxCNC (the >> motion logic, HAL, etc) on the PRU. Or you could implement >> something simpler, like the Marlin/Sprinter/Teacup/Grbl/etc., but >> written for the PRU. At this point, however, what you have is >> *NOT* LinuxCNC. > > Why would it be necessary to do anything on the PRU related to > LinuxCNC? What I am thinking is a simple Python interface between > LinuxCNC and the PRU; essentially a Python stub that takes all of > the motion logic and gcode output you mention and then translates > it to the PRUs on the BeagleBone for servo control...
If you understand the latency issues, then by all means port whatever you can to the PRU. The example code I pointed to earlier is basically a PRU replacement for the software stepgen or something like a Mesa card to generate the step/dir pulses, and requires LinuxCNC to be running with 'reasonable' latencies, essentially requiring PREEMPT_RT, Xenomai, or something similar. If you pull more functionality into the PRU, however, you could get by with worse latency performance on the Linux/ARM side. Good Luck! - -- Charles Steinkuehler char...@steinkuehler.net -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.11 (MingW32) Comment: Using GnuPG with Thunderbird - http://www.enigmail.net/ iEYEARECAAYFAlEMMm4ACgkQLywbqEHdNFx6rwCfXPAfLDwW5FQKLVeDcIhl25ju nNQAn2NULha0nGv9xEw4avnPdYjmwlfa =d1OT -----END PGP SIGNATURE----- ------------------------------------------------------------------------------ Everyone hates slow websites. So do we. Make your web apps faster with AppDynamics Download AppDynamics Lite for free today: http://p.sf.net/sfu/appdyn_d2d_jan _______________________________________________ Emc-developers mailing list Emc-developers@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-developers
