diff --git a/grbl/config.h b/grbl/config.h
index 963e0e2..8d2cf83 100644
--- a/grbl/config.h
+++ b/grbl/config.h
@@ -324,9 +324,9 @@
 // normal-open switch and vice versa.
 // NOTE: All pins associated with the feature are disabled, i.e. XYZ limit pins, not individual axes.
 // WARNING: When the pull-ups are disabled, this requires additional wiring with pull-down resistors!
-//#define DISABLE_LIMIT_PIN_PULL_UP
-//#define DISABLE_PROBE_PIN_PULL_UP
-//#define DISABLE_CONTROL_PIN_PULL_UP
+//#define DISABLE_LIMIT_PIN_PULL_UP     Don't use; pull-up control not ported to ARM yet. pull-up is always on.  
+//#define DISABLE_PROBE_PIN_PULL_UP     Don't use; pull-up control not ported to ARM yet. pull-up is always on.  
+//#define DISABLE_CONTROL_PIN_PULL_UP   Don't use; pull-up control not ported to ARM yet. pull-up is always on.    
 
 // Sets which axis the tool length offset is applied. Assumes the spindle is always parallel with
 // the selected axis with the tool oriented toward the negative direction. In other words, a positive
@@ -610,20 +610,16 @@
 
 // Define homing/hard limit switch input pins and limit interrupt vectors.
 // NOTE: All limit bit pins must be on the same port, but not on a port with other input pins (CONTROL).
-#define LIMIT_DDR        DDRB
-#define LIMIT_PIN        PINB
-#define LIMIT_PORT       PORTB
-#define X_LIMIT_BIT      1  // Uno Digital Pin 9
-#define Y_LIMIT_BIT      2  // Uno Digital Pin 10
-#ifdef VARIABLE_SPINDLE // Z Limit pin and spindle enabled swapped to access hardware PWM on Pin 11.
-  #define Z_LIMIT_BIT	   4 // Uno Digital Pin 12
-#else
-  #define Z_LIMIT_BIT    3  // Uno Digital Pin 11
-#endif
+#define LIMIT_DDR         LPC_GPIO0->FIODIR
+#define LIMIT_PIN         LPC_GPIO0->FIOPIN
+#define LIMIT_PORT        LPC_GPIO0->FIOPIN
+#define X_LIMIT_BIT       25  // X-MIN=24, X-MAX=25
+#define Y_LIMIT_BIT       27  // Y-MIN=26, Y-MAX=27
+#define Z_LIMIT_BIT	      29  // Z-MIN=28, Z-MAX=29
 #define LIMIT_MASK       ((1<<X_LIMIT_BIT)|(1<<Y_LIMIT_BIT)|(1<<Z_LIMIT_BIT)) // All limit bits
-#define LIMIT_INT        PCIE0  // Pin change interrupt enable pin
-#define LIMIT_INT_vect   PCINT0_vect
-#define LIMIT_PCMSK      PCMSK0 // Pin change interrupt register
+// hard/soft limit not ported    #define LIMIT_INT        PCIE0  // Pin change interrupt enable pin
+// hard/soft limit not ported    #define LIMIT_INT_vect   PCINT0_vect
+// hard/soft limit not ported    #define LIMIT_PCMSK      PCMSK0 // Pin change interrupt register
 
 // Define spindle enable and spindle direction output pins.
 #define SPINDLE_ENABLE_DDR    DDRB
diff --git a/grbl/limits.c b/grbl/limits.c
index 9beee95..d4eeb23 100644
--- a/grbl/limits.c
+++ b/grbl/limits.c
@@ -41,8 +41,8 @@ void limits_init()
   #endif
 
   if (bit_istrue(settings.flags,BITFLAG_HARD_LIMIT_ENABLE)) {
-    LIMIT_PCMSK |= LIMIT_MASK; // Enable specific pins of the Pin Change Interrupt
-    PCICR |= (1 << LIMIT_INT); // Enable Pin Change Interrupt
+    //LIMIT_PCMSK |= LIMIT_MASK; // Enable specific pins of the Pin Change Interrupt
+    //PCICR |= (1 << LIMIT_INT); // Enable Pin Change Interrupt
   } else {
     limits_disable();
   }
@@ -58,8 +58,8 @@ void limits_init()
 // Disables hard limits.
 void limits_disable()
 {
-  LIMIT_PCMSK &= ~LIMIT_MASK;  // Disable specific pins of the Pin Change Interrupt
-  PCICR &= ~(1 << LIMIT_INT);  // Disable Pin Change Interrupt
+  //LIMIT_PCMSK &= ~LIMIT_MASK;  // Disable specific pins of the Pin Change Interrupt
+  //PCICR &= ~(1 << LIMIT_INT);  // Disable Pin Change Interrupt
 }
 
 
@@ -69,7 +69,7 @@ void limits_disable()
 uint8_t limits_get_state()
 {
   uint8_t limit_state = 0;
-  uint8_t pin = (LIMIT_PIN & LIMIT_MASK);
+  uint32_t pin = (LIMIT_PIN & LIMIT_MASK);
   #ifdef INVERT_LIMIT_PIN_MASK
     pin ^= INVERT_LIMIT_PIN_MASK;
   #endif
diff --git a/grbl/settings.c b/grbl/settings.c
index c8edc14..e170d6a 100644
--- a/grbl/settings.c
+++ b/grbl/settings.c
@@ -335,7 +335,7 @@ uint32_t get_direction_pin_mask(uint8_t axis_idx)
 
 
 // Returns limit pin mask according to Grbl internal axis indexing.
-uint8_t get_limit_pin_mask(uint8_t axis_idx)
+uint32_t get_limit_pin_mask(uint8_t axis_idx)
 {
   if ( axis_idx == X_AXIS ) { return((1<<X_LIMIT_BIT)); }
   if ( axis_idx == Y_AXIS ) { return((1<<Y_LIMIT_BIT)); }
diff --git a/grbl/settings.h b/grbl/settings.h
index 4c2cfa4..213d46b 100644
--- a/grbl/settings.h
+++ b/grbl/settings.h
@@ -138,7 +138,7 @@ uint32_t get_step_pin_mask(uint8_t i);
 uint32_t get_direction_pin_mask(uint8_t i);
 
 // Returns the limit pin mask according to Grbl's internal axis numbering
-uint8_t get_limit_pin_mask(uint8_t i);
+uint32_t get_limit_pin_mask(uint8_t i);
 
 
 #endif