I don't know if the Arduino IDE has isochronous USB library but you can always implement it yourself. Of course it is already supported in the Linux side.
On Fri, Aug 10, 2018 at 10:04 AM Ken Strauss <[email protected]> wrote: > 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 > -- 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
