Remora - ethernet NVEM / EC300 / EC500 cnc board

Link for supporting development, yes I still need to get this up and more visible. Appreciate the support.

www.gofundme.com/f/remora-firmware-development

Hoping to move onto documentation improvement now the DMA stepgen is less in my head.

Can you share the DMA code or post a link?
I have given some thought to timer interrupt driven stepping, so would be interested to see how you do DMA

Hi Rod, 

The full source is in this branch:

github.com/scottalford75/Remora-RT1052-c...e/feature/DMAstepgen

The interesting sections are the interrupt driven DMA transfers between two ping pong buffers and the step pattern generator.

github.com/scottalford75/Remora-RT1052-c...mora-rt1052.cpp#L503

github.com/scottalford75/Remora-RT1052-c...epgen/DMAstepgen.cpp

Using the GPIO port toggle register means the step pattern buffer only needs to be filled when there is a change on the pin required. Ensure that we get both a rising and falling edge in the buffer has been most of the bug fixes.

How did you tune your pid? What’s your jitter if you run a latency test and hardware your running? I got myself a Dell Wyse 5060 with a quad core GX-424CC but I seem to get a hitter of like 70,000 maximum on the first thread. Anyways I’ve been beating the crap out of the pid loop to no end, 2000 pulses per mm and I run at 28mm a second maximum. I Can get my f-error to about 0.004 and then once the motor starts to decelerate it starts going up and peaks around 0.008 and that’s a lot to be honest because any latency can cause it to hit 0.01mm and now my milling has got weird wavy lines because of it….. anything below about 700mm/m seems to produce nearly no f-error like 0.002 and I can live with that. Any thoughts anyone?

FF1 = 0.032
FF2 = 0.0032
P = 48
I = 8

With the DMA stepgen? I found with the DMA stepgen that too high a Pgain causes to much oscillation, so I tamed it down to 10, which reduced the oscillation and following errors at high speed.

scotta wrote:

With the DMA stepgen? I found with the DMA stepgen that too high a Pgain causes to much oscillation, so I tamed it down to 10, which reduced the oscillation and following errors at high speed.

I noticed you set the base_freq inside the Hal to what your DMA step gen was. I have been matching this to the servo thread which we arnt using anymore…. Could this be causing my major failure in correcting f-error?