Klipper is the Open Source 'firmware' ecosystem that controls the printer. It's designed to make use of small systems and SoCs as linux hosts that run its series of distributed applications and services which APIs, UIs and connects to one or more microcontrollers. This replaces the Marlin firmware style systems that used to be prevalent for 3D printer control and greatly improves in the following areas:

* configuration by a simple text based configuration file, easily reloaded with to needing to reflash or reboot the printer host.

* supports “Smooth Pressure Advance”, input shaping, automated bed leveling, adaptive bed meshes for bed warpage compensation, z probes, real-time objects and exclusions, filament presence sensors, filament motion sensors, and filament width sensors, accelerometers (for input shaping)

* couples powerful processor technology and high precision stepper movements to form a high precision system offering excellent performance and low cost.

* capable of supporting highly complex calculations and stepper events precision of 25 micro-seconds or better, allowing for very fast printer acceleration and velocity.

* supports multiple microcontrollers, allowing separate controllers, allowing subsystem printer design (e.g. extruder, heaters, motion, fans) and supports multiple extruders

* implements a common timecode clock for synchronization to prevent drift across micro-controllers

* simple, programable macro based gcode

* simple, highly portable python codebase that's open source

See http://klipper.org