Marlin Compatibility

Marlin Compatibility Mode

Why have a Marlin Compatibility mode?

For 3D printing, there is a large number of utilities that are written to speak to Marlin or various other mostly-compatible variants. Even though there are several things that don't translate between Marlin and g2core, we can make an effort to at least accept gcode sliced for Marlin, and to be able to conditionally speak the Marlin protocol.

This gives the authors of those various utilities (assuming that they are still being maintained) some time to support the g2core protocol and gcode flavor.

What it's not

This will support the most-used gcode and protocol of Marlin, and nothing more.

What we don't support as Marlin (you have to use the g2core protocol for these):

• Configuration of the machine and various parameters
• Setup of motors, heaters, etc.
• Tuning PID, limit switch polarity, etc.

Also, this marlin support is a temporary option to ease transition, and will be deprecated once it becomes too difficult to support. This depreciation, once it has been scheduled, will be announced in the g2core changelog and on social media.

Communications protocol

There are a few concepts that convert more-or-less from g2core and Marlin:

g2core	Marlin	Notes
{"r":...,"f":[...]}	ok	In response to every sent gcode, g2core will return a response JSON, and Marlin will return ok. <br> (Marlin has an "advanced ok" option as well.)
{"he1st":210}	M104 S201 T1	Set temperature of extruder 1 to 210.
{"he1st":n}	M105	Request the set temperature of extruder 1 (g2core) or current extruder and bed (Marlin).
Nxxx (gcode)	Nxxx (gcode) * (checksum)	Marlin supports a checksum, and has special requirements on line numbers., where g2core accepts arbitrary line numbers and doesn't support a non-standard checksum.
{"out4":0.5}	M106 S128	Set output on the fan (or generic PWM output 4 for g2core) to 50%.

Supported Mxxx codes

• M104, M105, M109, M190, M108 - temperature control
  • On Marlin, you set the extruder temperature (and return immediately) with a M104 Snnn Tnnn
    • Snnn indicates the temperature in celsius
    • Tnnn (optional) indicates the tool, with the first being 0
  • On Marlin, if you wish to wait until the extruder is at temperature, change M104 to M109.
    • Cancel the wait with M108 (with no further words).
    • With Sxxx it will only wait for heating. Change the Sxxx to Rxxx to wait for cooling or heating.
  • On Marlin, the bed temperature is set with M140 Snnn, and it does NOT wait for the bed to heat up.
    • Snnn indicates the temperature in celsius
    • Wait for the heat bed with M190 Sxxx (for heating only) or M109 Rxxx (for both heating and cooling)

Unsupported