How does M115 work?
In people's starting scripts, I've seen variations of this line:
M115 U3.0.7 ; use the latest firmware version
How does this line work? Looking in online references, such as here, I don't see a description that includes the U parameter.
Do I have to update that line to match my printer's current firmware? Or does it mean "use at least version X.X.X?
Re: How does M115 work?
I realized I could answer this question precisely by looking in the code to see what it does. The source is here:
And the answer is here:
if (code_seen('U')) {
// Check the firmware version provided. If the firmware version provided by the U code is higher than the currently running firmware,
// pause the print and ask the user to upgrade the firmware.
show_upgrade_dialog_if_version_newer(++ strchr_pointer);
So the U string is the minimum version required. No need to update it each time you update the printer. You need to update the string if the gcode in the file requires a feature in a newer firmware release.
So I would change that comment to:
M115 U3.0.7 ; require at least this firmware version