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

Look forward to seeing how that goes, Tang Nano's are about 30 bucks AUD, two of them are still cheaper than any FPGA with a similar total pincount. I'm being selfish but that also means I stick with the same FPGA hardware for every machine I can possibly imagine making. 

Let me know if I can help with testing, I'm currently retrofitting my three machines to closed loop to the controller, so there's room for some hardware experimentation. 

if you have two (or more ) Tangnano, you can try it, you need the 'dev' branch and
2 free pins on each tangnano (RX / TX).
For short distance, you connect this pins direct (RX<->TX) or using RS485/RS422 converter for long distance.

Oh wait a minute, so you can have more than one extra FPGA? Alright then looks like I need to order some more Tang's.

yes, but please try it first, it's experimental !

github.com/multigcs/riocore/blob/dev/doc/RIOSUB.md

I think I need a different name for it
suggestions are welcome !

Quick question hopefully, I'm setting up my router with closed loop to the controller, apart from getting the scale right it's all working, my question is when you setup the scale in the pwm/dir config, it sets up the axis "scale in" to that, but leaves the scale out value at 1 or zero (can't remember exactly). At this value the axis will run away similar to having the encoder wires around the wrong way.

I can set it using the machine calibrate window within Linuxcnc but it gets overwritten every time setup is run. Then if you forget about it and an axis is close to end of travel, bad things can happen. 

I've most likely just missed where to put in the scale out value but I can't seem to find it.

Cheers.
Russell.