M915 Cool-Step strategy

[Ethelred]

I'm interested in trying to reduce extruder stepper heating by invoking the M915 Tnnn cool-step parameter. The steppers are NEMA14 pancake style with 5.0 mh x 7.0 ohm phase parameters. They operate in a low rpm regime. I have been unable to identify what the "T" value vs. current relationship is. A 16 bit integer "T" range is pretty broad. Any clues?

[dc42]

See section 5 in the TMC2660 datasheet at https://www.trinamic.com/fileadmin/assets/Products/ICs_Documents/TMC2660_datasheet.pdf. The M122 report includes the highest and lowest SG register values since M122 was last run, to help you find the correct coolstep setting.