[BUG] FT_MOTION Stepper pauses an instant with intervals of about 1.2-1.3 seconds

[marbocub]

Did you test the latest bugfix-2.1.x code?

Yes, and the problem still exists.

Bug Description

When using FT_MOTION, the stepper pauses an instant with intervals of about 1.2-1.3 seconds. It looks like that the pause is in sync with the update/redraw of the info screen on LCD. The faster the axis motion, the greater the shock by the pause.

A video is attached.

FT_MOTION-bump-bump.mp4

The vibration noise by the pause can be heard about every 1.2-1.3 seconds in the video. A "bump" caption is displayed when every pause occurs. It is also seen that the pause is in sync with the update of the info screen on LCD.

There are two round trips in the video. 60mm/s in the first round with 6 pauses and 40mm/s in the second round with 8 pauses. Thus the pause has nothing to do with the position on the axis.

Bug Timeline

I found it yesterday but I don't know when the issue started.

Expected behavior

I expected the stepper to move smoothly at a constant speed.

Actual behavior

The stepper pauses an instant with intervals of about 1.2-1.3 seconds.

Steps to Reproduce

1.Enable Fixed Time Motion in menu
2.Send motion gcode e.g. G1 X200 F3600
3.The issue is occurs

Version of Marlin Firmware

bugfix-2.1.x (2024-09-05)

Printer model

Sovol SV06 stock hardware

Electronics

Stock electronics

LCD/Controller

Sovol SV_NL_V1.3.1 controller (GD32F103RET6 and TMC 2209) with ENH12864Z-1 LCD, these are stock LCD/controller

Other add-ons

No response

Bed Leveling

ABL Bilinear mesh

Your Slicer

None

Host Software

None

Don't forget to include

• A ZIP file containing your Configuration.h and Configuration_adv.h.

Additional information & file uploads

Configurations.zip

[narno2202]

@marbocub , try to increase FTM_STEPPERCMD_BUFF_SIZE in Configuration_adv.h. The value can varie from printer to printer.

[konradmb]

I've seen the same behaviour on GD32F103 since at least 2023-12 but without FT_MOTION and with COLOR_UI. Recently after lowering the DMA timings (as described in comment in Marlin/src/HAL/STM32/tft/tft_fsmc.cpp) the pauses got shorter, but still the bumps produce an audible scratch. Changing the menu to some static screen stops them.
It's like diring the DMA transfer to the screen, everything stops, even the ISR.