diff --git a/grbl/settings.c b/grbl/settings.c
index a9c830e..e607506 100644
--- a/grbl/settings.c
+++ b/grbl/settings.c
@@ -45,7 +45,11 @@
              (DEFAULT_HOMING_ENABLE << BIT_HOMING_ENABLE) | \
              (DEFAULT_SOFT_LIMIT_ENABLE << BIT_SOFT_LIMIT_ENABLE) | \
              (DEFAULT_INVERT_LIMIT_PINS << BIT_INVERT_LIMIT_PINS) | \
-             (DEFAULT_INVERT_PROBE_PIN << BIT_INVERT_PROBE_PIN),
+             (DEFAULT_INVERT_PROBE_PIN << BIT_INVERT_PROBE_PIN)
+    #ifdef USE_ADC
+             | (DEFAULT_ENABLE_ADC << BIT_ADC_ENABLE)
+    #endif
+             ,
     .steps_per_mm[X_AXIS] = DEFAULT_X_STEPS_PER_MM,
     .steps_per_mm[Y_AXIS] = DEFAULT_Y_STEPS_PER_MM,
     .steps_per_mm[Z_AXIS] = DEFAULT_Z_STEPS_PER_MM,
@@ -294,6 +298,12 @@
           return(STATUS_SETTING_DISABLED_LASER);
         #endif
         break;
+      #ifdef USE_ADC
+        case 33:
+	  if (int_value) { settings.flags |= BITFLAG_ADC_ENABLE; }
+	  else { settings.flags &= ~BITFLAG_ADC_ENABLE; }
+	  break;
+      #endif
       default:
         return(STATUS_INVALID_STATEMENT);
     }