I too have found your instructions helpfull. Just today, taking advantage of the warmer weather, opened the gsarage door for working room behind the Sheldon lathe, and swapped the pi3 that has been running it for 2+ years, out for a pi4, running Raspbian buster v10.1 and a realtime kernel I built, and installed the debs of linuxcnc i've built on that pi4 over the last week. Not without some drama though.
Seems I had been power the 3 thru its OTG port, but the pi3 connector does mate with the pi4 version, so the fix was easy as the pi is upside down, exposing the bottom of the40 pin header, so it was easy enough to paste a couple wires to piins 2 and 6 to bring power into it from the 5 amp supply 4" away. But I also tried to drill a 5/8 hole fot hdmi cable access and miss-drilled it so its plugged in but at an angle that doesn't make a usable connection. So I'm going to have to move the back of the hole about 1/4" in oder to get a more straight on approach. Unforch, the alu at that point is 1/8" thick and yields very slowly to a dremel with a sanding drum.
So, wanting to see if the pi4 could move iron, I went to the console at the 6040 and logged into the rpi4, and ran linuxcnc from there. video a tad slow due to the network, but lcnc ran well as configured. If anything, smoother that ever.
So the weather folks are promising a warmer tomorrow and I may be able to fix the bad video connection.
I've had to hard code the spi speeds into hm2_rpspi as I make lcnc, as some of the changes made in adding the other 2 mesa cards, has cost it ts ability to respond to speed settings in the configure string passed to it from the bottom of the ini file.
No biggie for me, but will make it more difficult for the new user. As the defaults are too fast and it won't work. It can't read from a 7i90HD at the default 31250, and must be reduced to 25000 for spiclk_rate_rd.
So I'm rather happy overall, and the rpi4 should fix most of the glacial video I was getting with the pi3 running things. All I gotta do is get it hooked up.
My thanks for the tuts, they did help.
Cheers, Gene Heskett
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