On Tuesday 26 February 2019 10:59:14 [email protected] wrote: > hi again, > > Am 26.02.19 um 16:15 schrieb TJoseph Powderly: > > very interesting > > i use RPi3B with LinuxCNC and rt-preempt, headless over wired > > ethernet > > thanks for this feedback! > > I know, that it is possible to run linuxCNC on raspi itself. I build > one some years ago (http://erste.de/cerec1.avi) > I did it just for fun - but it works ;-) > > and with a working eth-connection, it should be no problem, to > increase the number of ports. the bottleneck is the > max. number of packets which can be sent (and read) by the > rt-kernel(s). > possible payload of this driver are over 300 IO-pins without > any changes in the timing behavior. > > because a raspberry or arduino is able to detect a rising and falling > edge, it is not necessary to waste a full square-wave for each > motor step. > > and again to the other posters: > I know, that several mesa-cards available. tey may be fine... > but I do not have one. > and linuxCNC works with a raspberry (or arduino) also - why not > publish a driver for it? > maybe, linuxCNC wins some new users in this way... > > but to use an edge-driven IO seems to be impossible without > touching stepgen.c (or wasting eth-bandwidth for obsolete squares) > If doing that, pay close attention to the setup and hold times when changing direction, giving your arduino time to stabilize, and also make sure that what the stepgen outputs on position.fb remains true to what the motor is assumed to be doing. That alone will change the internal code of stepgen.c because you'll have to increment, or decrement position.fb for every edge you send. It may even require a separate counter.
> regards > wicki > > > > > > _______________________________________________ > Emc-developers mailing list > [email protected] > https://lists.sourceforge.net/lists/listinfo/emc-developers Cheers, Gene Heskett -- "There are four boxes to be used in defense of liberty: soap, ballot, jury, and ammo. Please use in that order." -Ed Howdershelt (Author) Genes Web page <http://geneslinuxbox.net:6309/gene> _______________________________________________ Emc-developers mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/emc-developers
