Ethernet vs SPI

An Ethernet cable from the PC host to a Mesa card seems to be a more modern way to go. RZN has the RPi5 and Mesa 7I96S working flawlessly in some recent tests with Ethernet connection. Apparently the new Raspberry Pi 5 does not support SPI connection at the moment.

I am wondering why would someone want an SPI connection over Ethernet. Are there any advantages?

Thanks!

With the Pi4 you can turn off wifi (non of my cnc machines connect via wifi for security & latency reasons) and use the ethernet for network connection for updating, getting files, saves using SneakerNet.
Easy to adapt the 7c81, 7c80, 7i90 SPI firmware to a Spartan6 dev board.

Ethernet development started in 1973 and became a standard around 1983, Motorola original SPI spec was from about the early 1980s. So technically you could argue that Ethernet is the older technology & SPI is the newer.

It's up to personal choice, SPI is easier for the DIY route, less to worry about signal routing of the PCB.
Ethernet is a better choice if the motion control board is further away than a couple of inches from the computer. Tho the main issue some users have setting these up is giving the Mesa card and PC the same IP address.
EPP is also another option, once again easier for the DIY board, but kind of forgotten about due to not a great deal of modern motherboards not having a Printer Port on board, it's been reported that some plugin parallel port cards don't adhere to the EPP standard.

Thank you cornholio for the clarifications!

I'm with you about the security reasons. Using the ethernet for outside connection is a valid point. I was not planning on using it that way so it didn't occured to me. The CNC and its PC (SBC in this case) will be in a separate building from the PC used for CAD/CAM design. The program will be carried over on a thumbstick to be downloaded in the CNC's PC.

ProcksMFG wrote:

Thank you cornholio for the clarifications!

I'm with you about the security reasons. Using the ethernet for outside connection is a valid point. I was not planning on using it that way so it didn't occured to me. The CNC and its PC (SBC in this case) will be in a separate building from the PC used for CAD/CAM design. The program will be carried over on a thumbstick to be downloaded in the CNC's PC.

AKA SneakerNet.

If you are really worried about wifi security, Grab something like a Ubiquiti Nano at your shed and another at your house and set up a 150 Mb point to point link with a very loooong password.  You  still use legally 5G but in a frequency not used by normal Wifi. This stuff about wifi being insecure is rubbish. Just set it up securely! We did this on an 800 metre long link for years with no incidents. It passed over a lot of houses!

That way you can save your gcode directly into your ~/linuxcnc/gcode folder and just walk over...

All well and good, but mate some of us aren't that financially endowed.

I reckon SPI and ethernet must be about the same in ease of setup and use. I'm a total dummy but got ethernet going on my rpi5 without too much drama.

Mostly liked the fact that I could easy use any other PC if the Rpi didnt work out in my favor.