serial-protocol.md 1.7KB
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 is filament 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’