Prusa 3.9.0 for RAMPS 1.4 board

Prusa Firmware 3.9.0 (MK2S) for Arduino RAMPS 1.4 board

In my github repository (https://github.com/cimoalpacino/Prusa-Firmware/tree/MK2S_3.9.0_RAMPS) you can find and download the source code of a working Prusa 3.9.0 firmware running on an Arduino RAMPS board for my Prusa i3 Bear style 3D printer.

The latest official builds can be downloaded from Prusa Drivers. Pre-built development releases are also available here.

The firmware for the Original Prusa i3 printers is proudly based on Marlin 1.0.x by Scott Lahteine (@thinkyhead) et al. and is distributed under the terms of the GNU GPL 3 license.
Please read the whole document, especially the Important section at the bottom.

1. Specs

This firmware is configured for a Prusa Bear MK2S fitted with an Arduino RAMPS 1.4 and A4988.

Power supply

• Original Prusa 12V 240W PSU

Motherboard

• RAMPS 1.4

Printer frame

• Prusa i3 Bear Full Upgrade (MK2S)
• Prusa i3 Bear Printed parts on Thingiverse (Grégoire Saunier)
• Prusa i3 Bear Printed parts on Github (Grégoire Saunier)

Stepper motor drivers

• A4988 (from G3D) on X/Y/Z/E axis

Steppers

• X-axis: 1.8° motor
• Y-axis: 1.8° motor
• Z-axis: 1.8° motor
• Extruder: 1.8° motor
• Microstepping: 1/16

Heatbed

• Original Prusa MK42 12V with ATC Semitec 104GT-2 thermistor

Hotend

• Direct drive E3D V6 clone
• 20W 12V Heater Cartridge
• EPCOS 100k thermistor
• PINDA V1 (Reference: REP-PIN-DA0)

LCD Controller

• GADGETS3D G3D LCD/SD Controller
• (optional) RERAP Discount Smart Controller (can be easily set in Configuration_prusa.h)

Endstops

• Mehcanical: X/Y
• Inductive (PINDA): Z

Wiring Guide

• Reprap RAMPS 1.4

• PINDA wiring:

  | Endstop | Endstop pin | PINDA wire |
  | :---: | :---: | :---: |
  | Z-MIN | VCC (+) | Brown |
  | Z-MIN | GND (-) | Blue |
  | Z-MIN | SIGNAL (S) | Black |

2. Firmware

The firmware has been modified in many places and files to get it fully working.
All changes are marked with text /*RAMPS*/, so it can be easily traced using Find/Search option in text editors (or software like Visual Studio or VS Code).

Features and changes:

• added preheat option to preheat only nozzle (for maintanage, for example)
• added Init. SD card to manually initialize SD card if it fails to load when inserted in SD slot
• HW Setup menu changes to Live Z presets if a steel sheet is not used, otherwise it shows Sheets options
• removed Mode menu on LCD (since I use A4988, mode can't be set to silent, power or auto mode)
• mesh bed leveling has 3x3 and 7x7 options + magnets compensation
• new XYZ calibration
• linear advance 1.5
• Added a factory reset menu All but statistics to keep info about hours and filament used
• First layer calibration compatible also with 2.85mm filaments

Edited files:

• boards.h
• config.h
• configuration.h (check your probe offset settings)
  • #define X_PROBE_OFFSET_FROM_EXTRUDER -25
  • #define Y_PROBE_OFFSET_FROM_EXTRUDER -5 //-29
  • #define Z_PROBE_OFFSET_FROM_EXTRUDER -12.35
• heatbed_pwm.cpp
• Marlin.h
• Marlin_main.cpp

• mesh_bed_calibration.cpp
  (check settings for your setup so that the probe hits all bed points - use Pronterface output to help define the right values)

  #if MOTHERBOARD == BOARD_RAMPS_14_EFB
    //MK42 BED //if XYZ calibration fails, check serial output in Pronterface and adjust the values accordingly!
    36.5f - BED_PRINT_ZERO_REF_X - X_PROBE_OFFSET_FROM_EXTRUDER - SHEET_PRINT_ZERO_REF_X,   //36,5 - 2 - 23 - 0 = 11,5
    16.1f - BED_PRINT_ZERO_REF_Y - Y_PROBE_OFFSET_FROM_EXTRUDER - SHEET_PRINT_ZERO_REF_Y,   //16,4 - 9,4 - 5 - 0 = 1,7
  
    239.5f - BED_PRINT_ZERO_REF_X - X_PROBE_OFFSET_FROM_EXTRUDER - SHEET_PRINT_ZERO_REF_X,  //239,5 - 2 - 23 - 0 = 214,5
    16.1f - BED_PRINT_ZERO_REF_Y - Y_PROBE_OFFSET_FROM_EXTRUDER - SHEET_PRINT_ZERO_REF_Y,   //16,4 - 9,4 - 5 - 0 = 1,7
  
    239.5f - BED_PRINT_ZERO_REF_X - X_PROBE_OFFSET_FROM_EXTRUDER - SHEET_PRINT_ZERO_REF_X, //239,5 - 2 - 23 - 0 = 214,5
    212.4f - BED_PRINT_ZERO_REF_Y - Y_PROBE_OFFSET_FROM_EXTRUDER - SHEET_PRINT_ZERO_REF_Y, //212,4 - 9,4 - 5 - 0 = 198
  
    36.5f - BED_PRINT_ZERO_REF_X - X_PROBE_OFFSET_FROM_EXTRUDER - SHEET_PRINT_ZERO_REF_X,   //36,5 - 2 - 23 - 0 = 11,5
    212.4f - BED_PRINT_ZERO_REF_Y - Y_PROBE_OFFSET_FROM_EXTRUDER - SHEET_PRINT_ZERO_REF_Y   //212,4 - 9,4 - 5 - 0 = 198
  #else
  

• mesh_bed_calibration.h
  (check settings for your setup so that the probe hits all bed points - use Pronterface output to help define the right values)

  #define BED_ZERO_REF_Y (- 0.6f + Y_PROBE_OFFSET_FROM_EXTRUDER + 2.f) // -0.6 + 5 + 2 = 6.4
  #define BED_X0 (13.f - BED_ZERO_REF_X)    //13 - 1 = 12
  #define BED_Y0 (8.4f - BED_ZERO_REF_Y)    //8.4 - 6.4 = 2
  #define BED_Xn (216.f - BED_ZERO_REF_X) //216 - 1 = 215
  #define BED_Yn (204.4f - BED_ZERO_REF_Y)//204.4 - 6.4 = 198
  

• pins.h
• sm4.c
  • corrected pinout mapping for motors to reflect Ramps schematics
  • added function to re-calculate steps if we use different pulleys
• swi2c.c
• system_timer.c
• temperature.cpp
  • reconfigured timers
  • redefined old PWM for bed heating
• timer02.c:
  • reused old definition of timer02
• timer02.h:
  • reused old definition of timer02
• tmc2130.cpp
• uart2.c
• ultralcd.cpp
  • Edit parameter 0.f to a higher or lower value if having problem with Z calibration (line 3524)

    // increase (+) to go lower, decrease (-) to go higher
    current_position[Z_AXIS] = Z_MAX_POS + 0.f;
    

  • added "Init. SD card" menu option to manually initialize SD card if it fails when inserted in SD card slot
• w25x20cl.c
• w25x20cl.h
• xyzcal.cpp
  • added bed points for MK42 bed (set X and Y coordinates to fit your bed)

    #if MOTHERBOARD == BOARD_RAMPS_14_EFB
    const int16_t xyzcal_point_xcoords[4] PROGMEM = { 1150, 21450, 21450, 1150 };
    const int16_t xyzcal_point_ycoords[4] PROGMEM = { 600, 600, 19750, 19750 }; 
    #endif //!MOTHERBOARD == BOARD_RAMPS_14_EFB
    

Added new files:

• pins_Ramps.h
• Configuration_prusa.h

Pronterface

If having problems with calibration when the probe is searching the calibration points, I recommend to use Pronterface output to find the correct values.

3. IMPORTANT

If your setup is different than mine you have to modify parameters and values to fit your needs.
Use at your own risk!

Firmware was successfully compiled and tested with Arduino 1.8.5. Before compiling, be sure you have modified the file platform.txt.

• The platform.txt file can be found in Arduino instalation directory ("C:\Program Files (x86)\Arduino\hardware\arduino\avr"), or after Arduino has been updated at: "C:\Users\(user)\AppData\Local\Arduino15\packages\arduino\hardware\avr\(version)". If you can locate the file in both places, file from user profile is probably used.

  Add "-Wl,-u,vfprintf -lprintf_flt -lm" to "compiler.c.elf.flags=" before existing flag "-Wl,--gc-sections"

  For example: "compiler.c.elf.flags={compiler.warning_flags} -Os -g -flto -fuse-linker-plugin -Wl,-u,vfprintf -lprintf_flt -lm -Wl,--gc-sections"

Before making the inital Wizard calibration, it is mandatory to do a full factory reset to erase all eeprom data!

1. Press and hold the control knob
2. Power up the printer by turning the PSU switch on
3. Release the control know when you hear a beep

If done correctly, the LCD screen will show a menu with 4 options.

• Language
• Statistics
• Shipping prep
• All data
• All but statistics

Select All data and wait for it to complete.
After that you can continue with calibration.
If calibration fails in many retries, you may have to edit firmware parameters in calibration sections.
Whenever a new upload of firmware is done, the factory reset procedure must be repeated!

Enjoy and happy printing! :)