diff --git a/right/src/layer.c b/right/src/layer.c
new file mode 100644
index 0000000..fabe67f
--- /dev/null
+++ b/right/src/layer.c
@@ -0,0 +1,73 @@
+#include "layer.h"
+#include "slot.h"
+#include "module.h"
+#include "key_states.h"
+#include "keymaps.h"
+
+static bool heldLayers[LAYER_COUNT];
+static bool pressedLayers[LAYER_COUNT];
+
+void updateLayerStates(void)
+{
+    memset(heldLayers, false, LAYER_COUNT);
+    memset(pressedLayers, false, LAYER_COUNT);
+
+    for (uint8_t slotId=0; slotId<SLOT_COUNT; slotId++) {
+        for (uint8_t keyId=0; keyId<MAX_KEY_COUNT_PER_MODULE; keyId++) {
+            key_state_t *keyState = &KeyStates[slotId][keyId];
+            if (keyState->current) {
+                key_action_t action = CurrentKeymap[LayerId_Base][slotId][keyId];
+                if (action.type == KeyActionType_SwitchLayer) {
+                    if (!action.switchLayer.isToggle) {
+                        heldLayers[action.switchLayer.layer] = true;
+                    } else if (!keyState->previous && keyState->current) {
+                        pressedLayers[action.switchLayer.layer] = true;
+                    }
+                }
+            }
+        }
+    }
+}
+
+layer_id_t PreviousHeldLayer = LayerId_Base;
+
+layer_id_t GetActiveLayer()
+{
+    updateLayerStates();
+
+    // Handle toggled layers
+
+    static layer_id_t toggledLayer = LayerId_Base;
+
+    for (layer_id_t layerId=LayerId_Mod; layerId<=LayerId_Mouse; layerId++) {
+        if (pressedLayers[layerId]) {
+            if (toggledLayer == layerId) {
+                toggledLayer = LayerId_Base;
+                break;
+            } else if (toggledLayer == LayerId_Base) {
+                toggledLayer = layerId;
+                break;
+            }
+        }
+    }
+
+    if (toggledLayer != LayerId_Base) {
+        return toggledLayer;
+    }
+
+    // Handle held layers
+
+    layer_id_t heldLayer = LayerId_Base;
+
+    for (layer_id_t layerId=LayerId_Mod; layerId<=LayerId_Mouse; layerId++) {
+        if (heldLayers[layerId]) {
+            heldLayer = layerId;
+            break;
+        }
+    }
+
+    heldLayer = heldLayer != LayerId_Base && heldLayers[PreviousHeldLayer] ? PreviousHeldLayer : heldLayer;
+    PreviousHeldLayer = heldLayer;
+
+    return heldLayer;
+}
diff --git a/right/src/layer.h b/right/src/layer.h
index 0528c6a..c084bff 100644
--- a/right/src/layer.h
+++ b/right/src/layer.h
@@ -1,6 +1,10 @@
 #ifndef __LAYER_H__
 #define __LAYER_H__
 
+// Includes:
+
+    #include "fsl_common.h"
+
 // Macros:
 
     #define LAYER_COUNT 4
@@ -14,4 +18,13 @@
         LayerId_Mouse,
     } layer_id_t;
 
+// Variables:
+
+    extern layer_id_t PreviousHeldLayer;
+
+// Functions:
+
+    layer_id_t GetActiveLayer();
+
+
 #endif
diff --git a/right/src/usb_report_updater.c b/right/src/usb_report_updater.c
index c3c0110..b580db3 100644
--- a/right/src/usb_report_updater.c
+++ b/right/src/usb_report_updater.c
@@ -11,6 +11,7 @@
 #include "macros.h"
 #include "key_states.h"
 #include "right_key_matrix.h"
+#include "layer.h"
 
 static uint8_t mouseWheelDivisorCounter = 0;
 static uint8_t mouseSpeedAccelDivisorCounter = 0;
@@ -74,74 +75,6 @@ void processMouseAction(key_action_t action)
     wasPreviousMouseActionWheelAction = isWheelAction;
 }
 
-static bool heldLayers[LAYER_COUNT];
-static bool pressedLayers[LAYER_COUNT];
-
-void updateLayerStates(void)
-{
-    memset(heldLayers, false, LAYER_COUNT);
-    memset(pressedLayers, false, LAYER_COUNT);
-
-    for (uint8_t slotId=0; slotId<SLOT_COUNT; slotId++) {
-        for (uint8_t keyId=0; keyId<MAX_KEY_COUNT_PER_MODULE; keyId++) {
-            key_state_t *keyState = &KeyStates[slotId][keyId];
-            if (keyState->current) {
-                key_action_t action = CurrentKeymap[LayerId_Base][slotId][keyId];
-                if (action.type == KeyActionType_SwitchLayer) {
-                    if (!action.switchLayer.isToggle) {
-                        heldLayers[action.switchLayer.layer] = true;
-                    } else if (!keyState->previous && keyState->current) {
-                        pressedLayers[action.switchLayer.layer] = true;
-                    }
-                }
-            }
-        }
-    }
-}
-
-static layer_id_t PreviousHeldLayer = LayerId_Base;
-
-layer_id_t getActiveLayer()
-{
-    updateLayerStates();
-
-    // Handle toggled layers
-
-    static layer_id_t toggledLayer = LayerId_Base;
-
-    for (layer_id_t layerId=LayerId_Mod; layerId<=LayerId_Mouse; layerId++) {
-        if (pressedLayers[layerId]) {
-            if (toggledLayer == layerId) {
-                toggledLayer = LayerId_Base;
-                break;
-            } else if (toggledLayer == LayerId_Base) {
-                toggledLayer = layerId;
-                break;
-            }
-        }
-    }
-
-    if (toggledLayer != LayerId_Base) {
-        return toggledLayer;
-    }
-
-    // Handle held layers
-
-    layer_id_t heldLayer = LayerId_Base;
-
-    for (layer_id_t layerId=LayerId_Mod; layerId<=LayerId_Mouse; layerId++) {
-        if (heldLayers[layerId]) {
-            heldLayer = layerId;
-            break;
-        }
-    }
-
-    heldLayer = heldLayer != LayerId_Base && heldLayers[PreviousHeldLayer] ? PreviousHeldLayer : heldLayer;
-    PreviousHeldLayer = heldLayer;
-
-    return heldLayer;
-}
-
 void UpdateActiveUsbReports(void)
 {
     uint8_t basicScancodeIndex = 0;
@@ -152,7 +85,7 @@ void UpdateActiveUsbReports(void)
         KeyStates[SlotId_RightKeyboardHalf][keyId].current = RightKeyMatrix.keyStates[keyId];
     }
 
-    layer_id_t activeLayer = getActiveLayer();
+    layer_id_t activeLayer = GetActiveLayer();
     LedDisplay_SetLayer(activeLayer);
     static uint8_t previousModifiers = 0;