This is a modified release of the latest Marlin Firmware version 1.1.9, using the stock Ender-3 configurations and added support for Auto Bed Leveling. Due to flash memory constraints on Melzi boards, several lesser used options have been disabled to create space for the ABL features.

ABL Sensor settings have been configured in accordance with the information found via the Guide: How to Setup Auto Bed Leveling (Ender-3). If using another probe, mounting plate or any other changes are present, please make sure to adjust the values listed under ABL Probe Configurations as needed.

Thermal Runaway Protection and Cold Extrusion Prevention are ENABLED. These are safety standards and default in the Marlin Firmware.

enabled AUTO_BED_LEVELING_BILINEAR
enabled FIX_MOUNTED_PROBE
enabled Z_SAFE_HOMING

Flash Memory Usage: 98% (127 Kb)
Variable Memory Usage: 29% (4.79 Kb)

X_PROBE_OFFSET_FROM_EXTRUDER -40
Y_PROBE_OFFSET_FROM_EXTRUDER -10
Z_PROBE_OFFSET_FROM_EXTRUDER 2

LEFT_PROBE_BED_POSITION 10
RIGHT_PROBE_BED_POSITION 170
FRONT_PROBE_BED_POSITION 30
BACK_PROBE_BED_POSITION 190

Z_MIN_ENDSTOP_INVERTING true
Z_MIN_PROBE_ENDSTOP_INVERTING true