>________________________________________ >From: Charles Steinkuehler [char...@steinkuehler.net] >Sent: Friday, February 01, 2013 3:40 PM >To: EMC developers >Cc: Gregory Perry >Subject: Re: [Emc-developers] Python Library for the BeagleBone PRUSS > >-----BEGIN PGP SIGNED MESSAGE----- >Hash: SHA1 > >On 2/1/2013 2:16 PM, Gregory Perry wrote: >> Forget using Xenomai or RT_PREEMPT on the BeagleBone, check this >> out: >> >> http://hipstercircuits.com/?p=349#comment-269 > >Yep...we're already using the PRU to do stepgen: >http://git.mah.priv.at/gitweb/emc2-dev.git/blob/refs/heads/arm335x-hal-pru-module:/configs/pru-examples/stepgen.p > >But you still have to run Xenomai or PREEMPT_RT on the ARM or you get >things like 100 mS latency 'hiccups', which is unworkable for LinuxCNC. > >The only real way to operate with that much latency jitter would be to >port something like the Marlin firmware to run on the PRU and just >have Linux feed the PRU gcode. This is totally possible (see Bas' >BeBoPr project), but it's not LinuxCNC and you loose all the >flexibility of HAL, the ability to use the FPU in motion calculations, >etc. > >In fact, you also loose a C compiler (PRU coding is currently assembly >only), so unless you want to do everything in assembly, you get to >bring along your own tool chain. Of course, porting Forth to the PRU >would probably only take a few days.... <hmmmm> :) > >- -- >Charles Steinkuehler
Why not just have Python do the translation and feed the gcode to the PRU? The RISC cores on the PRU are completely autonomous from the Angstrom Linux kernel, so where would the 100ms hiccup come into play there? The process feeding gcode to the steppers? ------------------------------------------------------------------------------ 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
