Some v4.24 NV memory and slew speed issues

Henk Aling

Having used v3.16.o forever, I recently switched to the new stable v4.24g and found no major problems but some things work differently.

First, when I open the Bluetooth client on Android I get a message that there was an initialization failure of the non-volatile memory.  I have not noticed any problems related to this.  I don't recall seeing this with v3.16.o.

Secondly, I set the default slew speed to 2 deg/s in Config.h but it runs noticeably slower than v3.16.o, and the Android client shows 1.2 deg/s as the default speed at 64x.  Not a huge deal, but when I change the microstepping to 256x it tells me a slew speed of 0.3 deg/s.  Why is it not just 2 deg/s as I configured?

I want to get 256x working because it removes some discretization errors during guiding.  A 0.25" correction at 64x amounts to 1.78 pulses.  Depending on the error correction you could get 1 pulse or 2 pulses, which is relatively noisy.  If I can run at 256x then the discretization effect would be 4x smaller and I expect to see better guiding behavior.

I see an advanced driver text file that has a macro AXISn_DRIVER_FS_VHIGH that is used in the slew speed calculation I think, looking at StepMode.ino.  Is that something I can use to correct the slewing?

I was wondering if the slew speed was limited by TMC2130 vs TMC2130_QUIET vs TMC2130_VQUIET so I tried all 3 at 256x and they all result in 0.3 deg/s slew speed.

Henk Aling

Sorry I should have mentioned this is for a CNCv3 system with a custom pin map and with TMC2130 stepper drivers.  It does mode switching wired up by some jumpers.