112 lines
6.1 KiB
Markdown
112 lines
6.1 KiB
Markdown
# Features
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* Interrupt based movement with real linear acceleration
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* High steprate
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* Look ahead (Keep the speed high when possible. High cornering speed)
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* Interrupt based temperature protection
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* Preliminary support for [Matthew Roberts Advance Algorithm](http://reprap.org/pipermail/reprap-dev/2011-May/003323.html)
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* Full endstop support
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* SD Card support
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* SD Card folders (works in pronterface)
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* SD Card autostart support
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* LCD support (ideally 20x4)
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* LCD menu system for autonomous SD card printing, controlled by an click-encoder.
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* EEPROM storage of e.g. max-velocity, max-acceleration, and similar variables
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* many small but handy things originating from bkubicek's fork.
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* Arc support
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* Temperature oversampling
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* Dynamic Temperature setpointing aka "AutoTemp"
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* Support for [QTMarlin](https://github.com/bkubicek/QTMarlin), a very beta GUI for PID-tuning and velocity-acceleration testing.
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* Endstop trigger reporting to the host software.
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* Updated sdcardlib
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* Heater power reporting. Useful for PID monitoring.
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* PID tuning
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* [CoreXY kinematics](www.corexy.com/theory.html)
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* Delta kinematics
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* SCARA kinematics
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* Dual X-carriage support for multiple extruder systems
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* Configurable serial port to support connection of wireless adaptors.
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* Automatic operation of extruder/cold-end cooling fans based on nozzle temperature
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* RC Servo Support, specify angle or duration for continuous rotation servos.
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* Bed Auto Leveling.
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* Support for a filament diameter sensor, which adjusts extrusion volume
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The default baudrate is 250000. This baudrate has less jitter and hence errors than the usual 115200 baud, but is less supported by drivers and host-environments.
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## Differences and additions to the already good Sprinter firmware
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### Look-ahead
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Marlin has look-ahead. While sprinter has to break and re-accelerate at each corner,
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lookahead will only decelerate and accelerate to a velocity,
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so that the change in vectorial velocity magnitude is less than the xy_jerk_velocity.
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This is only possible, if some future moves are already processed, hence the name.
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It leads to less over-deposition at corners, especially at flat angles.
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### Arc support
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Slic3r can find curves that, although broken into segments, were ment to describe an arc.
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Marlin is able to print those arcs. The advantage is the firmware can choose the resolution,
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and can perform the arc with nearly constant velocity, resulting in a nice finish.
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Also, less serial communication is needed.
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### Temperature Oversampling
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To reduce noise and make the PID-differential term more useful, 16 ADC conversion results are averaged.
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### AutoTemp
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If your gcode contains a wide spread of extruder velocities, or you realtime change the building speed, the temperature should be changed accordingly.
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Usually, higher speed requires higher temperature.
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This can now be performed by the AutoTemp function
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By calling M109 S<mintemp> B<maxtemp> F<factor> you enter the autotemp mode.
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You can leave it by calling M109 without any F.
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If active, the maximal extruder stepper rate of all buffered moves will be calculated, and named "maxerate" [steps/sec].
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The wanted temperature then will be set to t=tempmin+factor*maxerate, while being limited between tempmin and tempmax.
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If the target temperature is set manually or by gcode to a value less then tempmin, it will be kept without change.
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Ideally, your gcode can be completely free of temperature controls, apart from a M109 S T F in the start.gcode, and a M109 S0 in the end.gcode.
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### EEPROM
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If you know your PID values, the acceleration and max-velocities of your unique machine, you can set them, and finally store them in the EEPROM.
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After each reboot, it will magically load them from EEPROM, independent what your Configuration.h says.
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### LCD Menu
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If your hardware supports it, you can build yourself a LCD-CardReader+Click+encoder combination. It will enable you to realtime tune temperatures,
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accelerations, velocities, flow rates, select and print files from the SD card, preheat, disable the steppers, and do other fancy stuff.
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One working hardware is documented here: http://www.thingiverse.com/thing:12663
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Also, with just a 20x4 or 16x2 display, useful data is shown.
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### SD card directories
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If you have an SD card reader attached to your controller, also folders work now. Listing the files in pronterface will show "/path/subpath/file.g".
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You can write to file in a subfolder by specifying a similar text using small letters in the path.
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Also, backup copies of various operating systems are hidden, as well as files not ending with ".g".
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### Autostart
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If you place a file auto[0-9].g into the root of the sd card, it will be automatically executed if you boot the printer. The same file will be executed by selecting "Autostart" from the menu.
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First *0 will be performed, than *1 and so on. That way, you can heat up or even print automatically without user interaction.
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### Endstop trigger reporting
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If an endstop is hit while moving towards the endstop, the location at which the firmware thinks that the endstop was triggered is outputed on the serial port.
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This is useful, because the user gets a warning message.
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However, also tools like QTMarlin can use this for finding acceptable combinations of velocity+acceleration.
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### Coding paradigm
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Not relevant from a user side, but Marlin was split into thematic junks, and has tried to partially enforced private variables.
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This is intended to make it clearer, what interacts which what, and leads to a higher level of modularization.
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We think that this is a useful prestep for porting this firmware to e.g. an ARM platform in the future.
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A lot of RAM (with enabled LCD ~2200 bytes) was saved by storing char []="some message" in Program memory.
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In the serial communication, a #define based level of abstraction was enforced, so that it is clear that
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some transfer is information (usually beginning with "echo:"), an error "error:", or just normal protocol,
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necessary for backwards compatibility.
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### Interrupt based temperature measurements
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An interrupt is used to manage ADC conversions, and enforce checking for critical temperatures.
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This leads to less blocking in the heater management routine.
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