Firmware For Prusa I3

Hi, I have a problem with my motors. All the X, Y , and Z motors can only move in one direction. I read about a post here and I typed in the M119 command. When the end-stops are pressed, the show Low, released and they show High. And sometimes, lets say I command it to move Left on the X-Axis in Pronterface, it can only move 0.1 step, and when I tried clicking 1 step, it stops. After that stop, I can't get it to move in any amount of direction along the axis unless I restart the printer. Tried repairing the solders, and tuning the pots, but no luck.

I suspect its a firmware problem? Which line of the firmware should I change? I tried Marlin and Sprinter, but they both show me same results.
Or better, is there a firmware typically for a Prusa I3?

I am using RAMPS 1.4,

You probably would get more help on configuring and troubleshooting general issues on an i3 printer in the area dedicated to that printer. The issues you are having (end stop connections) are a generic wiring issue rather than a problem with a Ramps board.

You need to do a number of modifications to your configuration.h file in order to get it to match your printer. Until that’s done, getting anything to move properly will be a problem. If your printer came as a kit, I’d contact the kit supplier to see if they have a pre-loaded version of Marlin that matches your printer.

Okay, I've got it working.
i'm using Marlin.
All the axes are running fine now. Problem is left with the Z stopper. As a Prusa I3, the Z endstop is supposed to be at the bottom, but I installed it at the top. According to Pronterface ( when I typed command m119 to check whether the Z stopper is working), it shows Z_MIN (this is the Z-stop on top). By default of the Marlin firmware, when I click Z Home at Pronterface, it goes up, but when I click on the + button, the Z axis goes down. Due to the fact that I installed it on top, I changed the Z endstop connection at the RAMPS board from Z_MIN to Z_MAX, and I used this part of the code:

#define INVERT_X_DIR false // for Mendel set to false, for Orca set to true
#define INVERT_Y_DIR true // for Mendel set to true, for Orca set to false
#define INVERT_Z_DIR true // for Mendel set to false, for Orca set to true
#define INVERT_E0_DIR false // for direct drive extruder v9 set to true, for geared extruder set to false
#define INVERT_E1_DIR false // for direct drive extruder v9 set to true, for geared extruder set to false
#define INVERT_E2_DIR false // for direct drive extruder v9 set to true, for geared extruder set to false

// ENDSTOP SETTINGS:
// Sets direction of endstops when homing; 1=MAX, -1=MIN
#define X_HOME_DIR -1
#define Y_HOME_DIR -1
#define Z_HOME_DIR 1


And it worked fine. The Z axis moves up when I clicked Home, (which is what I wanted) and it goes up too when i clicked +.
However, when I started to test print, everything goes wrong.

I believe I need to re-calibrate the Z Home to be 0.1mm above the heat bed? How do I tell the printer to set that? I tried bringing it down to 0.1mm and typed G92 Z0. I thought it worked, but when I started the test print program, again, it wants to go back to the top. Something is still amiss. I wonder what?

So to put question in another way, how do I tell the printer (via firmware), to set its HOME by a distance of lets say 0.1mm away from the heated bed even though my Z end stop is mounted on top of the printer.

With only one end stop, and it on the wrong end of Z, you will spend a *lot* of time cranking the (very slow) Z motors every time you hit the home button. Even if you could come up with a way to accurately translate the Z, that would make this approach a real pain to use. I'd move the switch.