Remora - Rpi Software Stepping Using External Microcontroller via SPI

Inkscape normally works in pixels, that has to be set in mm or inches in the drop down menu top center, right after the dimension values.

@Aaroncnc, the way I tested was pretty crude in that I just went with longer wires and made stuff or ran fake runs with nothing in the extruder until I got SPI errors then figured the workable length was between the shorter and the longer which still failed but after a bunch of testing.

My hand wired 2x5 connector adapters failed after a time at 70cm long ribbon cable and worked really well 20cm. My pcb based 2x5 connector adapters have been working so far with only 1 SPI error over a few hours of testing on the 70cm ribbon cable.

70cm is very long and should be way more than anyone would normally need.

To do some validation of the PCB based SPI connector adapter boards I have a long 700mm GLCD ribbon cable between the rPi4 and SKR1.4t adapters. The GCode file is one doing a ~100mm diameter spiral having 50 rotations at 200mm/s and I have that in a loop running 50 times and each loop raises Z by 2mm.

I've run it 8 times now without any SPI errors. I see on the DRO the Vel is pegged at 9000 most of the time.

I've attached the arcBlendTest file below.

I hit a few snags.
1. My neighbour doesn't understand my obsession with this
2. I think I killed my X axis driver.

I finally made a crappy vid  Aircut  ( streamable.com/5yszzq )
Warning it's headache inducing, bandwidth consuming.
I think it's not bad for a bent X axis leadscrew with a .5" pitch, atleast I think I have the scale correct.
In any case it's just a proof that the controller works,  pretty stable too.

Oh and this jscut.org/ is a good start for a newbie it imports svg from inkscape .

@Scott  I bump the PRU_BASEFREQ to 200kHz just to see what happens, the video is the result.
But after re-run for a couple of times the x axis driver is dead.  I just realized that there's no configurable option to
change the step pulse width. The TB6600 I'm using apparently has a minimum pulse of 5 uSec probably more.

Hello
I'd like to use Remora as a pru for a bridgeport style milling machine.
I'm using a r-pi4 2gb and a btt skr 1.4
Motors are closed loop steppers, with a simple step+dir style command,
for pru and linuxcnc they appear as open-loop.
Before trying Remora I tried the basic hardware with marlin 2 on the skr and is working ok.
Now with remora I have 2 problems:

1- home switches:
I'd like to logically invert the signal coming from remora, but the option "Invert" for digital pin seem to have no effect.
I solved this using a "not" in hal but, anyway since it is in remora config I'd like to know if I'm making some mistake

2- what is step generator maximum step rate?
I'm having problems at rates higher than approx 18000-20000 steps per second.
I have 8000step per mm on Z axis, and the driver is happy up to about 140-150mm/min,
at higher speeds remora feedback start to lag behind the command significantly.
Is this normal? Maybe I'm doing somehing wrong, since marlin on the same hw
is able to go happily up to 1800mm/min (also if the machine is not happy to go that fast image missing /media/kunena/emoticons/dizzy.png ).
This is also true for X and Y that have 2133 steps/mm and top at 400-500mm/min,
that is enough for my needs.

In attachment my conf.txt file
Thanks
Fabio 

I have started adding hal code clips into the remora docs.
remora-docs.readthedocs.io/en/latest/software/hal-examples.html

If you guys have any interesting or unique code in your hal if you could copy paste it here i can easily add it.
Would be nice if you could give it s short write up so a user can just copy paste the code and have a basic idea of why.