raspberry pi 3 model b+ support realtime

spma wrote: Hi everyone!
I just want to leave my experience here because I've been able to successfully use an Pi3b+ with a Mesa 7i92 + 7i77 + 7i84.

Interesting. You wouldn't normally expect that to work as the Pi3 ethernet is on the USB bus and that tends to make accurate timing impossible.

Pi4 has he ethernet on the PCIe bus, and then the servo thread at 1mS works fine with an ethernet board.

andypugh wrote: Interesting. You wouldn't normally expect that to work as the Pi3 ethernet is on the USB bus and that tends to make accurate timing impossible.

True but I tested it thoroughly and the 2.5ms of servo_thread period was more than enough for a 30yo SLOW lathe with a maximum joint precision of 0.05mm... and it outputted that precision while machining

andypugh wrote: Pi4 has he ethernet on the PCIe bus, and then the servo thread at 1mS works fine with an ethernet board.

Yes, the Pi4 would now be a better choice, but we're talking about a project I started almost 2 years ago...
The next project I'll get a chance I'll invest some time testing it with the Pi4.

Simão A.