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

meister wrote:

one error on the board, but with a little fix, all works fine

 

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I've followed-up your idea of using a Wiz Lite module rather than the diff.pair and matching nets. This freed up a lot of estate and so I squeezed in a GP8101S (pwm-2-analog), a step-up 5~12V MT3608 and an Omron G6K-2F relay. Caters a VFD 0-10V.

Word of caution on the Wiz Lite Module though. In a hostile environment it switches from full/half duplex 10 to 100mbps all on its own. This is because the 3 PMODE pins are left floating. If you can, jump-wire those UP on a 4k7 and that'll sort it. 

Amazing solution you've put up, Olivier. Hope the guys will get that Tang Nano 9k and experiment how excellent RIO is.  

I finally finished designing my modular design idea: github.com/festlv/rioctrl-hw

Still have to actually build & test it- I'm fairly sure that there will be f-ups, just hope that nothing too major

Looks good. Lots of hard work. Lots of thought gone into it.


Generally when I've been designing my boards I've followed the mesa example where all the signals from the FPGA that will be controller something go through a FET bus switch with a pullup resistor to 5v on the "world side"(I'm a cruddy old guy lol, I like 5v). Gives you bi directional voltage translation, and works fine even with the 2.5MHz SmartSerial signals (when I use mesa firmware tho my design also can run rio with no issues). To drive outputs I add a buffer or just connect directly to a simple Parallel Port breakout board.

Have you thought about screw terminals for the outputs ?
With regards to the differential outputs for the stepper drivers, it would take some serious noise to have any affect when driving an opto. I've used plain old 74 series 540/541 powered by 5 volts with no issues for years, plenty of drive there. And generally the cable length isn't all that great from between the step\dir source & destination.

Tommy linked a video to a guy that experiments with noise & shielded cables, very interesting.

For 5v to 3.3v translation 74lvc is a good candidate.

small test-setup with 'smart-meter' over modbus:

 
 
 

fest wrote:

I finally finished designing my modular design idea: github.com/festlv/rioctrl-hw

Still have to actually build & test it- I'm fairly sure that there will be f-ups, just hope that nothing too major
 

Hi festl,
had somehow overlooked your post, something is wrong with my email notification

very nice !!!

will take a closer look and am looking forward to the first tests

i knew you were working on something modular but you exceeded all my expectations, respect !

WOW !!!!!

Mecanix wrote:

Word of caution on the Wiz Lite Module though. In a hostile environment it switches from full/half duplex 10 to 100mbps all on its own. This is because the 3 PMODE pins are left floating. If you can, jump-wire those UP on a 4k7 and that'll sort it. 
 

give me more details please ,experience or in theory? would everything stop working or would it cause persistent issues? Ive been running these for about 8 months now and havent seen anything too bad, so i am curious

cakeslob wrote:

give me more details please ,experience or in theory? would everything stop working or would it cause persistent issues? Ive been running these for about 8 months now and havent seen anything too bad, so i am curious

Nothing bad at all, it's a great module overhaul. The downside of floating state pins is randomness, therefore not a persistent issue.

Fwiw the PMODE select pins have internal/weak resistors. Meaning; if the environment the system is operating in is an ideal one then most likely the internal weak resistors will be sufficient. However, (in my case), if there is quite a bit of noise/emi/gamma rays/bitflips/coffee/radiation/traffic/manyothers... you may experience strange 10mbps half-duplex startups and/or strange network negotiation. The workaround/fix to that is to harden the PMODE pins' state with pullups (4K7) - see source schematic (pardon my crayon!). 

Hey guys I have been going through some install hell so I have decided to start a new thread on the topic, so we don't clog up this thread with silly questions.
I'm going to copy ColdTurkey's example on the Remora thread using the live install version of LinuxCNC Debian, so anybody following will have the same starting point.
I am guessing anybody familiar with setting this up will overcome simple hurdles without thinking, but those of us that aren't really computer guys will struggle.
My only question I'll ask here though is should I do this for LinuxCNC-RIO or Riocore ?
Cheers.
Russell.