MarlinFirmware
[BUG] FT_MOTION Stepper pauses an instant with intervals of about 1.2-1.3 seconds
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.
https://github.com/user-attachments/assets/6d186433-e09a-46a1-8770-116f4f21dd06
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
- [X] A ZIP file containing your
Configuration.handConfiguration_adv.h.
Additional information & file uploads
@marbocub , try to increase FTM_STEPPERCMD_BUFF_SIZE in Configuration_adv.h. The value can varie from printer to printer.
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 during the DMA transfer to the screen, everything stops, even the ISR.
This happens in COLOR_UI even without DMA(with TFT_SHARED_IO) at least on GD32F303. Affects both classic planner and FT motion.
From https://github.com/MarlinFirmware/Marlin/pull/25394 the PR that added FT_MOTION
"This feature uses a lot of SRAM for the step event buffer and does a lot of extra computation to apply shaping, so it requires a powerful board.
STM32F103 or GDGD32F103 are NOT powerful boards. They don't even have hardware floating point units. (which is not listed as a requirement, but certainly helps)
