flexi-bot/docs/marlin/_gcode/M209.md

tag	title	brief	author	requires	group	codes	notes	parameters	examples
m0209	Set Auto Retract	Enable / disable auto-retraction.	thinkyhead	FWRETRACT	motion	M209	Requires `FWRETRACT`. Most slicers today can generate [`G10`](/docs/gcode/G010.html)/[`G11`](/docs/gcode/G011.html). But this option is useful for older G-code. Though not currently very popular, both volumetric extrusion and firmware-based retraction (and/or [`M209`](/docs/gcode/M209.html)) make G-code more immune to changes from one machine to another, and permit changing the hardware without needing to re-slice. See related codes [`G10`](/docs/gcode/G010.html), [`G11`](/docs/gcode/G010.html), [`M207`](/docs/gcode/M207.html), and [`M208`](/docs/gcode/M208.html).	tag optional description values S false Set Auto-Retract on/off tag type flag bool

Enable or disable automatic retraction. This option is meant to help slicers that don't support G10/G11. But it can be used to override retraction in any G-code.

When auto-retract is enabled, all reversed E-only moves are treated as retraction. (Recover moves are also automatically overridden.) When disabled, E retraction derives from G-code.