On Saturday 26 October 2019 13:11:35 Gene Heskett wrote: > On Saturday 26 October 2019 11:16:47 andy pugh wrote: > > On Sat, 26 Oct 2019 at 00:23, Marshland Engineering < > > > > [email protected]> wrote: > > > Can a PI be used > > > directly to drive the 2 stepper drives for this application ? > > > Maybe just needs a break out board for the IO connections. > > > > I don't think it is 100% simple with LinuxCNC as there isn't a hal > > driver for the Pi GPIO. > > https://github.com/LinuxCNC/linuxcnc/tree/master/src/hal/drivers > > Machinekit has one (hal_gpio) > > https://github.com/machinekit/machinekit/tree/master/src/hal/drivers > > But it hasn't been ported across to LinuxCNC. I don't know how much > > work it would be to do so. > > The hm2_rpspi.c has been patched to work with 3 cards on the pi4 now. > > But it the process of the patch devel, the ability to set the spi com > speed from the config string passed at loadrt time has been lost, > requiring for the 7i90HD card, that the variable spiclk_rate_rd in my > case be lowered from 31250 to 25000, and the driver then rebuilt along > with the rest of linuxcnc. The mesa 7C80,81 cards may be different > yet, I've no src of those cards on site. But a/o 3 or 4 days ago, the > rpi4 has been installed to run my Sheldon 11x56 and doing it far > smoother than the pi3b I put in 2+ years ago ever dreamed of doing. I > am a VERY happy camper. I now have much faster video, and I have added > looping code to lathe_pawn.ngc and let it carve 10 of them out of air, > without logging a single latency overshoot to the terminal screen when > I shut it down. > One thing I neglected to mention is that its relatively easy to blow pin drivers in the relatively inexpensive 7i90hd with noises from other parts of the system, and I eventually bought a trio of the 7i42TA cards, which adapt the 50 pin 7i90hd headers to green screw terminals at the same time they have 7i90hd protective noise snubbers. Between moving the pi to its own box and other wireing fixups, the noise disappeared, but the ease of wiring it up makes the 7i42TA's well worth the cost. And now with the rpi4, its running the machine with less latency drama than I am getting from 2 of the almost legendary intel D525-MW motherboards, which I bought two of 10 years ago when you folks went almost orgasmic over them. > > Cheers, Gene Heskett
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) If we desire respect for the law, we must first make the law respectable. - Louis D. Brandeis Genes Web page <http://geneslinuxbox.net:6309/gene> _______________________________________________ Emc-users mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/emc-users
