[BUG] Laser problem with latest FW

[kpbicka]

Did you test with a precompiled firmware?

Yes, and the problem still exists.

Bug Description

The firmware version where laser works correctly with correct execution of G-code:
Ender3S1-F4-CVLM-20230812.bin

laser settings:
Ender3S1 with Marlin G-code
BaudRate 250.000
S-value max = 9999
Laser Control Commands = M03/M05

On latest firmware laser does not work or works incorrectly
firmwares versions with the problem:

Ender3S1-F4-CVLM-20230904.bin
Ender3S1-F4-CVLM-20240127.bin

incorrect execution of G-code - during the execution of G-code the laser does not turn on
laser settings same as earlier:

Ender3S1 with Marlin G-code
BaudRate 250.000
S-value max = 1000 (any value of this parameter does not solve problem)
Laser Control Commands = M03/M05 (other M106/M107 or Inline do not fix the problem)

Software used: LightBurn.V1.7.03.dmg for MacOS (downgrade LightBurn version not solve problem)
Advanced settings - Laser Control - Toggle Laser - Laser ON (Laser diode begin lid on minimal brightness (as usual))

example of G-code generated by LightBurn that is sent to the printer (console out)

Starting stream
G21
G90
M9
M05
G0 X30 Y20 F0
Layer C00
M03 S1000
G1 X50F6000
M9
M05
G90
G0 X0 Y0 F0
echo:Unknown command: "M9"
echo:Unknown command: "M9"
Stream completed in 0:00

Laser behavior:
bright flash, move to the starting point of the drawing, burning the drawing (but the laser does not emit power (like in idle mode) and nothing is drawn), at the end a bright single flash, move to the home position

on the LightBurn forum (https://forum.lightburnsoftware.com/t/ender-3-s1-pro-tips-tricks-and-suggestions/141611) they advise using
Start G-code command = M3
This advice does not completely help
Here is the laser behavior:
bright flash, move to the starting point of the drawing, burning the drawing at an unknown power (the laser emits power, but the program sets the value to 1%), at the end a bright single flash, move to the home position

Here is the G-code

Starting stream
M3
G21
G90
M9
M05
G0 X30 Y20 F0
Layer C00
M03 S10
G1 X50F6000
M9
M05
G90
G0 X0 Y0 F0
echo:Unknown command: "M9"
echo:Unknown command: "M9"
Stream completed in 0:00

Expected laser behavior - moving to the starting point, burning at a given power, turning off the laser. Unfortunately, no settings can achieve success.

Previously, on the Ender3S1-F4-CVLM-20230812.bin firmware, no settings were required and the laser worked correctly.
If no change settings in LightBurn and downgrade mriscoc-firmware to Ender3S1-F4-CVLM-20230812.bin then laser works fine!

maybe there is a problem with slow PWM in last FW?

Bug Timeline

No response

Expected behavior

No response

Actual behavior

No response

Steps to Reproduce

No response

Version of Professional Firmware

FIRMWARE_NAME:Marlin 2.1.3 MRiscoC Ender3S1-F4-CVLM, based on bugfix-2.1.x (Jan 27 2024 19:26:39)

Printer model

Creality Ender3S1 F4

Electronics

No response

LCD/Controller

No response

Other add-ons

No response

Bed Leveling

None

Your Slicer

None

Host Software

None

Additional information & file uploads

No response

[mriscoc]

Something was changed in the Marlin code base that maybe broke the laser functionality, unfortunately I don't have currently the hardware to do the test to solve this issue.