WS281x LED Status will intercept M150 commands to control the LEDs.
Commands should be formatted as such:
M150 [P{intensity}] [R{intensity}] [G{intensity}] [B{intensity}] [W{intensity}]
All of the parameters are optional, and can be included in any order. If an option is not included, its value is 0 - as a result sending an empty M150 command will turn the LEDs off.
It's not recommended to send an empty M150, and instead use @ commands to turn the LEDs on and off.
Examples:
On a standard RGB WS281x strip, the W parameter sets an equal value of R, G and B on the LEDs.
If you have an RGBW strip and enable the 'Use dedicated white' setting, the W parameter will control the white LEDs only.
Sending any of R, G or B with the command takes priority over the W.
Parameter
Explanation
P
Brightness, max 255. If not included, defaults to maximum brightness in the settings
R
Red intensity, max 255.
G
Green intensity, max 255. Can also be U for Marlin compatibility.
B
Blue intensity, max 255.
W
White intensity, max 255.