A CPU with Ethernet and a builtin FPGA/CPLD to implement the SPI ports would probably be a very good device for an SPI router, probably also very cheap. Packets could routed to ordinary computer running Linuxcnc as is today or split so that real time part is in the simple device. It is not to different from a PLC I have on my workplace, it is mounted on a din rail without any user interface except a reset start/stop/reset button, there is an Ethernet connecter used for the programming, it is also possible to connect user interface if needed but I have not investigated how it communicate.
I remember someone here talked about someone implementing PWM on a PRU. I did on an ordinary Micro controller once, I guess code could be reused but I do not want to do it again. A timer with compare registers plus a few other things usually available in micro controllers is really good at this. On Thu, 28 Mar 2019 08:05:26 +0700 TJoseph Powderly <tjt...@gmail.com> wrote: > Gene hello > > > > On 03/27/2019 08:13 PM, Gene Heskett wrote: > > On Wednesday 27 March 2019 08:12:48 TJoseph Powderly wrote: > > > >> ( list apology, I seem to have replied to posters rather than to the > >> list, and several times :-( > >> > >> re SPI comms Linuxcnc SBC microcontrollers ... > >> > >> it has been said on this mail list, > >> that SPI is a good candidate for a bus technology to work _with_ > >> realtime. > >> > >> heres some work in that vein (maybe overlooked) > >> > >> yeltrow's work: > >> a generic spi hal module so you can use other SPI devices ( rpi, > >> arduino, mcp23s17, ENC28J60, theres a lot of spi stuff to hang onto > >> such a bus ) > >> https://www.forum.linuxcnc.org/24-hal-components/28851-spi-bus-generic > >> -driver-and-st-l6480 > >> > > Interesting driver for the big stuffs. However, I wonder if yeltrow is > > aware of rpspi.ko, now part of LCNC. Not parport based but gpio, > > written specificly for the rpi3b. And I'm using it, writing to a Mesa > > 7i90 at 42 megabaud, and reading back from the 7i90 at 25 megabaud > > useing only 4 gpio pins for 2 or 3 target devices. > I dont find source rpspi.c in my sources. > cant google it except to find messages from you. > > My RIP source tree is DGarr's external offset branch. > > I dont have raspi.kp either. > > Where are these files? > > The files I was speaking of were generic spi utilities, > not RPi to Mesa communication modules, > They were attempts to make SPI available on any hardware platform to any > SPI device. > They are attempts only ( one uses a parport but i guess that could be > altered to gpio ) > But from the parport, the author connects to many different SPI devices. > > What file builds rpspi.ko ? > > Maybe its private/unpublished work from Matsche ? > > I cant find it on https://github.com/LinuxCNC/linuxcnc either. > > Plz lemmeno > TomP > > Perusal of that code might be of help to yeltrow. gpio seems to be about > > 10x faster than trying to simulate SPI over a parport. The 7i90 has > > both modes depending on the firmware loaded. > > > >> the files are on the forum for members linuxcnc-upload-2015-12-03.tar > > So this work handily predates rpspi.ko. Still, theres obviously things to > > be learned from the rpi version. > > > >> erste's work: > >> for ethernet circumventing usb ( via spi > >> interesting as spi and ethernet seem to be future avenues > >> http://erste.de/ethraw/README > >> > >> theres other efforts but less coupled to the spi grail > >> > >> tomp > >> > >> > >> _______________________________________________ > >> Emc-users mailing list > >> Emc-users@lists.sourceforge.net > >> https://lists.sourceforge.net/lists/listinfo/emc-users > > Cheers, Gene Heskett > > > > _______________________________________________ > 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
