Thanks Sam, I'll take a look at it. Here's the Pi4 with the 7i92H on the hardwire Ethernet and the WiFi is enabled. I snapped a shot with my phone rather than a screen grab. I had played a couple of videos and moved windows around. If this is 'poor' for a Pi4 with LinuxCNC then the default parameters for this install are incorrect. I'll post a photo of the hardware. John
> -----Original Message----- > From: Sam Sokolik [mailto:samco...@gmail.com] > Sent: March-06-22 2:43 PM > To: Enhanced Machine Controller (EMC) > Subject: Re: [Emc-users] Pi4 with LinuxCNC and MESA 7i92H > > hey - I have the configs / Pi files here > > https://electronicsam.com/images/greenmachine/config/ > > sam > > On Sun, Mar 6, 2022 at 12:16 PM Chris Albertson <albertson.ch...@gmail.com> > wrote: > > > On Sun, Mar 6, 2022 at 3:40 AM Robin Szemeti via Emc-users < > > emc-users@lists.sourceforge.net> wrote: > > > > > The Pi4 and a Mesa ethernet card seemed like a brilliant idea when I > > bought > > > mine ... I now regret it. The networking nightmare it has caused is > > > painful. There is no WiFi down in my shed, only wired ethernet, so I had > > > to put in a WiFi to ethernet bridge, connectivity is odd, sometimes it > > > appears on the network, sometimes it doesn't. > > > > > > Any bright ideas on how to add a second ethernet port to the Pi? > > > > > > > First off to you really need the Pi to be on the Internet while it is > > cutting metal? If not the simple solution is to connect the Pi, Mesa board > > and home Ethernet to a switch and pull the plug on the home ethernet when > > the Pi is cutting metal. > > > > If you want a more elegant solution then buy a "managed" switch then allows > > you to define a V-LAN and have the switch basically remove the > > external Ethernet when you don't want it. doing the same thing as > > unplugging it. You would need to write a script to reconfigure the switch. > > > > But you could add a second Ethernet port using a USB3-Ethernet dongle like > > this amazon.com/TP-Link-Ethernet-UE306-... > > < > > https://www.amazon.com/TP-Link-Ethernet-UE306-Foldable-10-11-10- > 15/dp/B09GRL3VCN/ref=asc_df_B09GRL3VCN/?tag=hyprod- > 20&linkCode=df0&hvadid=563598683736&hvpos=&hvnetw=g&hvrand=7967367747260015957&hvpone=&hvptwo=&hvqmt=&hvd > ev=c&hvdvcmdl=&hvlocint=&hvlocphy=9031026&hvtargid=pla-1457086693568&th=1 > > > > > > > Using a second Ethernet port does not remove the processing the Pi has to > > do to look at the packets on the second port. The manages switch or > > simply unplugging the cable completely solves the issue > > > > > > > > > > > > On Sun, 6 Mar 2022 at 02:19, gene heskett <ghesk...@shentel.net> wrote: > > > > > > > On Saturday, 5 March 2022 19:12:45 EST John Dammeyer wrote: > > > > > I had to clean off my workbench for another project so the Pi4 has > > been > > > > > boxed for a short while. But in mentioning LCNC to a friend who was > > > > > buying a used PC (Intel NUC7i5BNH) that he should download the latest > > > > > LinuxCNC Image and run the latency test to see how well it would work > > > > > for LCNC. > > > > > > > > > > I then mentioned I'd had my Pi4 running it but also told him about > > the > > > > > one time latency message I get every time I boot it. That I suspect > > > > > it's due to also have the WiFi running in addition to the Ethernet to > > > > > 7i92H. > > > > > > > > > > So that's the background. > > > > > > > > > > Now the question. > > > > > > > > > > If LCNC has been ported over to a Pi4 should there even be a latency > > > > > issue? It's a fixed hardware platform so that message on start-up > > has > > > > > always puzzled me but since it's just for playing around on the bench > > > > > and not doing real machining I've never really cared. > > > > > > > > > I've been running an old sheldon I rebuilt with ball screws etc. I have > > > > beem told that the hardware of the pi does not make use of the isolcpus > > > > command in the same manner that x86 hdwe does which may explain my > > > > latency testing results being in the 12 u-sec territory which my setup > > > > with a 7i90 using the spi interface seems to tolerate very well until I > > > > fire up FF while the test is running, and FF is a hog, quickly pushing > > > > the latency out to the 200 u-sec territory. However I have run a 50 > > loop > > > > repeat of the lathe_pawn.ngc program, carving air while I browsed the > > > > news sites and I can count on one hnd the number of times my lathe > > > > actually stuttered in half and hours fooling around. > > > > > > > > I used the 7i90 and the spi interface to it, in order to preserve the > > > > pi's internet connectivity. The speed of the spi interface is amazing > > and > > > > I watched it on a 4 channel, 350mhz scope for hours trying to spot a > > com > > > > timing error that caused a repeat transmission going either way. It > > > > hasn't happened. There has been zero com errors. > > > > > > > > That protocol uses 3 gpio lines as a serial port, sending data in 32 > > bit > > > > packets to the 7i90, and getting its reply's back, sending and > > receiving > > > > clocks logged as it initializes the card at lcnc startup: > > > > hm2_rpspi: SPI0/CE0 clock rate: 41666000/25000000 Hz, VPU clock rate: > > > > 500000000 Hz > > > > hm2_rpspi: SPI0/CE0 write clock rate calculated: 41666666 Hz > > (clkdiv=12) > > > > hm2_rpspi: SPI0/CE0 read clock rate calculated: 25000000 Hz (clkdiv=20) > > > > Note pleaase thats sending at 41.666666 megahertz, and receiver the > > cards > > > > answers at 25.000000 megahertz > > > > > > > > I'll submit that we do NOT have in the wintel cpu family, a com speed > > > > capable of moving data at 10% of that speed/bandwidth product. And has, > > > > as near as I can tell, zero effect on network performance while its > > doing > > > > it. So my goal of not sacrificing my network to use a cat5 interfaced > > > > card like the 7i92 was quite handily achieved. > > > > > > > > If it wasn't for the lack of an spi capable interface on the wintel > > > > stuff, AND the combined cost of the 7i90HD + 3 7i42TA's, I would have > > > > converted every machine here to be run by the rpi4b. > > > > > > > > Not having tested the 7i90HD fed by a parport, in epp mode so you get > > all > > > > 8 bits per byte, I'll let Peter testify as to whether or not, the > > 7i90HD, > > > > using its 26 pin interface to a pc parport, is as fast AND dependable. > > I > > > > suspect its just as dependable as an epp port can be, but considerably > > > > slower. > > > > > > > > FWIW, I'm using SSD's on usb-3 adapter cables for workspace and swap on > > > > that rpi4b, lots easier on the u-sd, and on raspi's buster I can build > > a > > > > realtime kernel in about 35 minutes, and I can build LCNC master from > > > > github and install the english of it, in about 75 minutes. > > > > > > > > About 45 minutes to build a 5.16.2 preempt-rt kernel, but I can't build > > > > LCNC, bullseyes python-3.9.2 is to new and breaks LCNC. python-3.7 > > from a > > > > buster install works fine. > > > > > > > > The other thing that impresses me, is the rpi4b's phenominal uptimes. I > > > > have a teeny ups on it and a 20kw nat gas generator in the back yard > > that > > > > fires up in 6 or 7 seconds so it never sees a power failure. Uptimes > > have > > > > been more than 6 months several times. The monitor draws 11 watts, the > > > > idling pi about 8 or 9, so I only shut it down to change boot cards. > > > > > > > > I had LCNC running but doing nothing all the time it took me to type > > > > this, shutdown reports latency: > > > > task: 409277 cycles, min=0.000056, max=0.017526, avg=0.006107, 0 > > latency > > > > excursions (> 10x expected cycle time of 0.006000s) > > > > > > > > Draw your own conclusions as to whether its fit to run machinery. > > Works > > > > fine for me. > > > > > > > > My $0.02. > > > > > > > > > Ideas? > > > > > > > > > > Thanks > > > > > John > > > > > > > > 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, 1940) > > > > If we desire respect for the law, we must first make the law > > respectable. > > > > - Louis D. Brandeis > > > > > > > > > > > > > > > > > > > > > > > > _______________________________________________ > > > > Emc-users mailing list > > > > Emc-users@lists.sourceforge.net > > > > https://lists.sourceforge.net/lists/listinfo/emc-users > > > > > > > > > > _______________________________________________ > > > Emc-users mailing list > > > Emc-users@lists.sourceforge.net > > > https://lists.sourceforge.net/lists/listinfo/emc-users > > > > > > > > > -- > > > > Chris Albertson > > Redondo Beach, California > > > > _______________________________________________ > > Emc-users mailing list > > Emc-users@lists.sourceforge.net > > https://lists.sourceforge.net/lists/listinfo/emc-users > > > > _______________________________________________ > Emc-users mailing list > Emc-users@lists.sourceforge.net > https://lists.sourceforge.net/lists/listinfo/emc-users
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