LinuxCNC-RIO - RealtimeIO for LinuxCNC based on FPGA (ICE40 / ECP5)

I see in sources component encoder (vin_quadencoderz).
ohh need test all

I recently stumbled upon this topic- looks really impressive project. I'm currently building a milling machine and was planning on using linuxcnc and mesa, however this looks a tempting alternative for my use case.

I'm not afraid from building the needed electronics and fiddling with building the gateware as I have some leftover Colorlight ecp5 modules, have experience with open source fpga tools (though, with LiteX/amaranth, very rudimentary verilog knowledge), and have another cnc machine planned, so the work would be amortised over more than a single machine.

My main question would be: what might I be missing out by using this instead of mesa? Are there known features not implemented yet (I think my needs are rather modest: up to 5 step/dir axes up to 6 incremental encoders, digital inputs/outputs). I'm not really sure where the closed motion control loop is being executed usually- is it Linuxcnc, or does mesa have support to do closed loop stepgen in hardware (which doesn't seem to be supported here, right?)

Hi fest,
thanks
I don't have any mesa cards, so I can't tell you what's missing.
But if you miss something, let me know and I'll try to add it.
I think mesa also uses the pid controllers in linuxcnc.

About the colorlight boards i have to say that the networkport is not supported, you need 4 free pins for SPI and either a UDP2SPI bridge or a raspberry.

5 step/dir axes up to 6 incremental encoders should be no problem if you have enough pins.

EDIT: do you know this project ?: forum.linuxcnc.org/27-driver-boards/4442...roller-board?start=0

Hmm, thanks for the pointer, LiteXCNC also looks quite interesting. Direct Ethernet support is indeed intriguing, though it also appears that IO options are more limited in LiteXCNC.

The modules I have are SODIMM, with FPGA, SDRAM and 2x GigE phy, not the boards with LED buffers, so pin availability is not a problem. I'll probably design my carrier board to be compatible with both projects (so far it seems that LinuxCNC-RIO only needs an SPI header while LitexCNC needs the phy) and see what works best for me.

if you mean this board: tomverbeure.github.io/2021/01/22/The-Col...velopment-board.html

i have a test board for it:
 

without Ethernet and stepper/encoder/IO interfaces on extra cards
 

Nice, this is similar to what I had in mind. Is the board design open source?

was not the plan, it's only for testing the concept, but you can have it:

multixmedia.org/color_i5.tgz
(eagle-files, but you can import it into kicad)

where you living ?
i have some PCB's of this version, if you need one....

Thanks, had to add https:// to the link but I could download and import them. It doesn't look that I would gain much over prototyping on the colorlight devboard though, but I do like the modular backplane/module approach.

I've wanted to do something similar for custom instruments (kinda like modular chassis National Instruments and others are making), but it'd make a neat CNC controller- customizable with modules targeting particular servo drive brands or encoder connectors etc). Though it's probably too much for me to tackle building both an overengineered controller and machine at the same time

Those SODIMM boards look like they have a reasonable priced spartan6-16x, the Linsn mini901,
which could probably just load Hostmot2. same with the Colorlight i9+ which has spartan7, which I think ive seen someone port HM2 to the spartan7

Colorlight i9plus-v6.1 has a Xilinx chip
Colorlight i9-v7.2 has a Lattice chip
Colorlight i5-v7.0 has a Lattice Chip

More info here
github.com/wuxx/Colorlight-FPGA-Projects

github.com/sleepybishop/artix_hostmot2

github.com/sleepybishop/mojo_hostmot2