diff --git a/grbl/cpu_map.h b/grbl/cpu_map.h
index c93b420..07a902a 100644
--- a/grbl/cpu_map.h
+++ b/grbl/cpu_map.h
@@ -534,10 +534,11 @@
   #define CONTROL_INVERT_MASK   CONTROL_MASK // May be re-defined to only invert certain control pins.
 
   // Define probe switch input pin.
-  #define PROBE_DDR       NotUsed
-  #define PROBE_PIN       NotUsed
-  #define PROBE_PORT      NotUsed
-  #define PROBE_BIT       5  // Uno Analog Pin 5
+  // Borrow Y Max limit port for probe
+  #define PROBE_DDR       LPC_GPIO1->FIODIR
+  #define PROBE_PIN       LPC_GPIO1->FIOPIN
+  #define PROBE_PORT      LPC_GPIO1->FIOPIN
+  #define PROBE_BIT       27  // borrowing y-max pin
   #define PROBE_MASK      (1<<PROBE_BIT)
 
   // The LPC17xx has 6 PWM channels. Each channel has 2 pins. It can drive both pins simultaneously to the same value.
diff --git a/grbl/probe.c b/grbl/probe.c
index 60c9073..67072f7 100644
--- a/grbl/probe.c
+++ b/grbl/probe.c
@@ -22,7 +22,7 @@
 
 
 // Inverts the probe pin state depending on user settings and probing cycle mode.
-uint8_t probe_invert_mask;
+uint32_t probe_invert_mask;
 
 
 // Probe pin initialization routine.
@@ -50,7 +50,13 @@ void probe_configure_invert_mask(uint8_t is_probe_away)
 
 
 // Returns the probe pin state. Triggered = true. Called by gcode parser and probe state monitor.
-uint8_t probe_get_state() { return((PROBE_PIN & PROBE_MASK) ^ probe_invert_mask); }
+uint8_t probe_get_state() { 
+	if ((PROBE_PIN & PROBE_MASK) ^ probe_invert_mask) {
+		return 1;
+	} else {
+		return 0;
+	}
+}
 
 
 // Monitors probe pin state and records the system position when detected. Called by the