Interesting! Is there support for isochronous transfers at both ends? Do both ends support host/target roles? Can you configure both ends for arbitrary VID/PID?
> -----Original Message----- > From: Chris Albertson [mailto:[email protected]] > Sent: Friday, August 10, 2018 12:34 PM > To: Greg Bentzinger; Enhanced Machine Controller (EMC) > Subject: Re: [Emc-users] Pi with a side of SPI > > If you are trying to get data from a Pi to an Arduino at a reasonably fast > rate. Use USB. The Arduino has built-in USB as does the PI. USB is > great because it is a balanced, differential signal. It is way-faster then > you need for this purpose. It is also very easy to use from the software > in both Arduino and Pi. The Arduino software sees the USB cable as a > serial port and the Pi can see it the same way > > If you are worried about packet delay and unpredictable latency that look > into using USB's isochronous transfer mode. > > > > > On Thu, Aug 9, 2018 at 8:32 PM Greg Bentzinger via Emc-users < > [email protected]> wrote: > > > > > > > Greg - To Gene - and list > > > > > > If the RPi can use SPI over a 250mm length cable at rated speed then it is > > a great option. > > > > No? How about a 150mm cable? > > > > If the signal can't get off the host PCB and to the target PCB reliably > > then the whole issue is a non starter moot point. > > > > Maybe if there was an off the shelf adapter PCB to rig a hat sandwich. For > > 90% of users PCB level mods are beyond what they signed on for. > > > > SPI is faster than needed which is nice to have extra available free time > > in the loop. > > > > But MACH 3, other than smooth stepper users was almost all para port. LCNC > > proved it could drive parallel ports just fine. Higher level controls Like > > Pico Systems and Mesa ECP/EPP based FPGA cards have proven that an > ECP/EPP > > connection is plenty effective speed wise. > > > > > > For my mill retrofit I went with a small pile of Mesa cards starting with > > a 5i25/7i77 with several additional SSerial cards added to the mix (mega > > overkill, and probably not really needed) > > > > I still have a 7i43 I bought way back, and I have a lathe conversion that > > has been on a back burner for a few years. I was thinking of driving the > > 7i43 with a new/old stock DM510 I have had on the shelf NIB long enough > > that any warranty has long expired. Sadly the DM510 is actually less > > powerful than the RPi, only thing in the DM510 favor is I can stuff it with > > 4gb ram. > > > > I have renewed my interest in the Pi because I'm looking at some simple > > applications which using the Pi as the front end driving an Arduino with > > GRBL is plenty. One application is a powered feed with auto reset for my > > horizontal bandsaw, a second axis could be used to auto feed the stock for > > the next cut using a vise clamped/unclamped sensor switch to > > inhibit/resume. Another RPi + Arduino GRBL is a stand alone programmable > > 4th axis indexer for manual milling - plus having connectors that would > > allow bypassing the Pi/GRBL and driving the stepper (with encoder feedback) > > from LCNC. > > > > Another project that is just on the wish list at this point is a 5 axis > > tool grinder, but it might become 8-9 axis if I include programmable form > > wheel dressing. (bring Whiskey and Asprin) > > > > Currently all conversions are on hold as I am trying to make space to > > shoehorn in the machinery I purchased from my Uncles Estate. I have a > Okuma > > LK 350mm lathe, Bridgeport, another horizontal bandsaw and a Harig 6x18 > > Surface grinder. Been so much rain the soil is too soft for the forklifts > > to unload. So delivery keeps getting pushed back. Thankfully I'm not > > backlogged currently because after the machines are in, then I have to go > > back to the old site and remove the wiring and phase converter and install > > the outlets at my shop. > > > > Greg > > > > > > ---------------------------------------------------------------------------- -- > > Check out the vibrant tech community on one of the world's most > > engaging tech sites, Slashdot.org! http://sdm.link/slashdot > > _______________________________________________ > > Emc-users mailing list > > [email protected] > > https://lists.sourceforge.net/lists/listinfo/emc-users > > > > > -- > > Chris Albertson > Redondo Beach, California > ---------------------------------------------------------------------------- -- > Check out the vibrant tech community on one of the world's most > engaging tech sites, Slashdot.org! http://sdm.link/slashdot > _______________________________________________ > Emc-users mailing list > [email protected] > https://lists.sourceforge.net/lists/listinfo/emc-users ------------------------------------------------------------------------------ Check out the vibrant tech community on one of the world's most engaging tech sites, Slashdot.org! http://sdm.link/slashdot _______________________________________________ Emc-users mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/emc-users
