Firmware2/Marlin/src/feature/mmu/mmu2-serial-protocol.md
2020-11-18 01:27:21 -06:00

1.7 KiB

Startup sequence

When initialized, MMU sends

  • MMU => 'start\n'

We follow with

  • MMU <= 'S1\n'
  • MMU => 'okFirmware version\n'
  • MMU <= 'S2\n'
  • MMU => 'okBuild number\n'

#if (12V_mode)

  • MMU <= 'M1\n'
  • MMU => 'ok\n'

#endif

  • MMU <= 'P0\n'
  • MMU => 'FINDA status\n'

Now we are sure MMU is available and ready. If there was a timeout or other communication problem somewhere, printer will be killed.

  • Firmware version is an integer value, but we don't care about it
  • Build number is an integer value and has to be >=126, or =>132 if 12V mode is enabled
  • FINDA status is 1 if the filament is loaded to the extruder, 0 otherwise

Build number is checked against the required value, if it does not match, printer is halted.

Toolchange

  • MMU <= 'TFilament index\n'

MMU sends

  • MMU => 'ok\n'

as soon as the filament is fed down to the extruder. We follow with

  • MMU <= 'C0\n'

MMU will feed a few more millimeters of filament for the extruder gears to grab. When done, the MMU sends

  • MMU => 'ok\n'

We don't wait for a response here but immediately continue with the next gcode which should be one or more extruder moves to feed the filament into the hotend.

FINDA status

  • MMU <= 'P0\n'
  • MMU => 'FINDA status\n'

FINDA status is 1 if the is filament loaded to the extruder, 0 otherwise. This could be used as filament runout sensor if probed regularly.

Load filament

  • MMU <= 'LFilament index\n'

MMU will feed filament down to the extruder, when done

  • MMU => 'ok\n'

Unload filament

  • MMU <= 'U0\n'

MMU will retract current filament from the extruder, when done

  • MMU => 'ok\n'

Eject filament

  • MMU <= 'EFilament index\n'
  • MMU => 'ok\n'