diff --git a/config.h b/config.h
index c6027b9..d93b89c 100644
--- a/config.h
+++ b/config.h
@@ -23,9 +23,9 @@
 
 #define VERSION "0.0"
 
-#define X_STEPS_PER_MM 94.488188976378
-#define Y_STEPS_PER_MM 94.488188976378
-#define Z_STEPS_PER_MM 94.488188976378
+#define X_STEPS_PER_MM (94.488188976378*16)
+#define Y_STEPS_PER_MM (94.488188976378*16)
+#define Z_STEPS_PER_MM (94.488188976378*16)
 
 #define STEP_PULSE_MICROSECONDS 30
 
@@ -73,9 +73,11 @@
 #define LIMIT_MASK ((1<<X_LIMIT_BIT)|(1<<Y_LIMIT_BIT)|(1<<Z_LIMIT_BIT))
 
 // Use this line for default operation (step-pulses high)
-#define STEPPING_INVERT_MASK 0
+ #define STEPPING_INVERT_MASK 0
 // Uncomment this line for inverted stepping (step-pulses low, rest high)
 // #define STEPPING_INVERT_MASK (STEP_MASK)
+// Uncomment this line to invert all step- and direction bits
+// #define STEPPING_INVERT_MASK (STEPPING_MASK)
 // Or bake your own like this adding any step-bits or directions you want to invert:
 // #define STEPPING_INVERT_MASK (STEP_MASK | (1<<Z_DIRECTION_BIT))
 
diff --git a/stepper.c b/stepper.c
index bb218dd..7b8da0a 100644
--- a/stepper.c
+++ b/stepper.c
@@ -77,7 +77,7 @@ SIGNAL(SIG_OUTPUT_COMPARE1A)
 SIGNAL(SIG_OVERFLOW2)
 {
   // reset stepping pins (leave the direction pins)
-  STEPPING_PORT = (STEPPING_PORT & ~STEPPING_MASK) | (STEPPING_INVERT_MASK & STEPPING_MASK); 
+  STEPPING_PORT = (STEPPING_PORT & ~STEP_MASK) | (STEPPING_INVERT_MASK & STEP_MASK); 
 }
 
 // Initialize and start the stepper motor subsystem
@@ -85,7 +85,7 @@ void st_init()
 {
 	// Configure directions of interface pins
   STEPPING_DDR   |= STEPPING_MASK;
-  STEPPING_PORT = (STEPPING_PORT & ~STEPPING_MASK) | STEPPING_INVERT_MASK;
+  STEPPING_PORT = (STEPPING_PORT & ~STEPPING_MASK); //| STEPPING_INVERT_MASK;
   LIMIT_DDR &= ~(LIMIT_MASK);
   STEPPERS_ENABLE_DDR |= 1<<STEPPERS_ENABLE_BIT;