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This RepRap firmware is a mashup between <ahref="https://github.com/kliment/Sprinter">Sprinter</a>, <ahref="https://github.com/simen/grbl/tree">grbl</a> and many original parts.
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.
Differences and additions to the already good Sprinter firmware:
Also, with just a 20x4 or 16x2 display, useful data is shown.
*SD card folders:*
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".
You can write to file in a subfolder by specifying a similar text using small letters in the path.
Also, backup copies of various operating systems are hidden, as well as files not ending with ".g".
*SD card folders:*
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.
First *0 will be performed, than *1 and so on. That way, you can heat up or even print automatically without user interaction.
*Endstop trigger reporting:*
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.
This is useful, because the user gets a warning message.
However, also tools like QTMarlin can use this for finding acceptable combinations of velocity+acceleration.
*Coding paradigm:*
Not relevant from a user side, but Marlin was split into thematic junks, and has tried to partially enforced private variables.
This is intended to make it clearer, what interacts which what, and leads to a higher level of modularization.
We think that this is a useful prestep for porting this firmware to e.g. an ARM platform in the future.
A lot of RAM (with enabled LCD ~2200 bytes) was saved by storing char []="some message" in Program memory.
In the serial communication, a #define based level of abstraction was enforced, so that it is clear that
some transfer is information (usually beginning with "echo:"), an error "error:", or just normal protocol,
necessary for backwards compatibility.
*Interrupt based temperature measurements:*
An interrupt is used to manage ADC conversions, and enforce checking for critical temperatures.
This leads to less blocking in the heater management routine.
* M42 - Change pin status via gcode Use M42 Px Sy to set pin x to value y, when omitting Px the onboard led will be used.
* M80 - Turn on Power Supply
* M81 - Turn off Power Supply
* M82 - Set E codes absolute (default)
* M83 - Set E codes relative while in Absolute Coordinates (G90) mode
* M84 - Disable steppers until next move, or use S<seconds> to specify an inactivity timeout, after which the steppers will be disabled. S0 to disable the timeout.
* M85 - Set inactivity shutdown timer with parameter S<seconds>. To disable set zero (default)
* M92 - Set axis_steps_per_unit - same syntax as G92
* M201 - Set max acceleration in units/s^2 for print moves (M201 X1000 Y1000)
* M202 - Set max acceleration in units/s^2 for travel moves (M202 X1000 Y1000) Unused in Marlin!!
* M203 - Set maximum feedrate that your machine can sustain (M203 X200 Y200 Z300 E10000) in mm/sec
* M204 - Set default acceleration: S normal moves T filament only moves (M204 S3000 T7000) im mm/sec^2 also sets minimum segment time in ms (B20000) to prevent buffer underruns and M20 minimum feedrate
* M205 - advanced settings: minimum travel speed S=while printing T=travel only, B=minimum segment time X= maximum xy jerk, Z=maximum Z jerk, E=maximum E jerk
* M208 - set recover=unretract length S[positive mm surplus to the M207 S*] F[feedrate mm/sec]
* M209 - S<1=true/0=false> enable automatic retract detect if the slicer did not support G10/11: every normal extrude-only move will be classified as retract depending on the direction.
* M218 - set hotend offset (in mm): T<extruder_number> X<offset_on_X> Y<offset_on_Y>
* M220 S<factorinpercent>- set speed factor override percentage
* M221 S<factorinpercent>- set extrude factor override percentage
The third one tells the angle in 2 situations: Probing (165º) and resting (60º). Check this with command M280 P0 S{angle} (example: M280 P0 S60 moves the servo to 60º)
By default, RAMPS have no power on servo bus (if you happen to have a multimeter, check the voltage on servo power pins).
In order to get the servo working, you need to supply 5V to 5V pin.. You can do it using your power supply (if it has a 5V output) or jumping the "Vcc" from Arduino to the 5V RAMPS rail.
These 2 pins are located just between the Reset Button and the yellow fuses... There are marks in the board showing 5V and VCC.. just connect them..
If jumping the arduino Vcc do RAMPS 5V rail, take care to not use a power hungry servo, otherwise you will cause a blackout in the arduino board ;-)
Next you need to define the Z endstop (probe) offset from hotend.
My preferred method:
* a) Make a small mark in the bed with a marker/felt-tip pen.
* b) Place the hotend tip as *exactly* as possible on the mark, touching the bed. Raise the hotend 0.1mm (a regular paper thickness) and zero all axis (G92 X0 Y0 Z0);
* d) Raise the hotend 10mm (or more) for probe clearance, lower the Z probe (Z-Endstop) with M401 and place it just on that mark by moving X, Y and Z;
* e) Lower the Z in 0.1mm steps, with the probe always touching the mark (it may be necessary to adjust X and Y as well) until you hear the "click" meaning the mechanical endstop was trigged. You can confirm with M119;
* f) Now you have the probe in the same place as your hotend tip was before. Perform a M114 and write down the values, for example: X:24.3 Y:-31.4 Z:5.1;
* g) You can raise the z probe with M402 command;
* h) Fill the defines bellow multiplying the values by "-1" (just change the signal)
* \#define X_PROBE_OFFSET_FROM_EXTRUDER -24.3
* \#define Y_PROBE_OFFSET_FROM_EXTRUDER 31.4
* \#define Z_PROBE_OFFSET_FROM_EXTRUDER -5.1
The following options define the probing positions. These are good starting values.
I recommend to keep a better clearance from borders in the first run and then make the probes as close as possible to borders:
* \#define LEFT_PROBE_BED_POSITION 30
* \#define RIGHT_PROBE_BED_POSITION 140
* \#define BACK_PROBE_BED_POSITION 140
* \#define FRONT_PROBE_BED_POSITION 30
A few more options:
* \#define XY_TRAVEL_SPEED 6000
X and Y axis travel speed between probes, in mm/min.
Bear in mind that really fast moves may render step skipping. 6000 mm/min (100mm/s) is a good value.
* \#define Z_RAISE_BEFORE_PROBING 10
* \#define Z_RAISE_BETWEEN_PROBINGS 10
The Z axis is lifted when traveling to the first probe point by Z_RAISE_BEFORE_PROBING value
and then lifted when traveling from first to second and second to third point by Z_RAISE_BETWEEN_PROBINGS.
All values are in mm as usual.
That's it.. enjoy never having to calibrate your Z endstop neither leveling your bed by hand anymore ;-)
