diff --git a/module_usb_audio/clocking/clockgen.xc b/module_usb_audio/clocking/clockgen.xc
index 9180d298..41234b48 100644
--- a/module_usb_audio/clocking/clockgen.xc
+++ b/module_usb_audio/clocking/clockgen.xc
@@ -262,7 +262,7 @@ void clockGen (streaming chanend c_spdif_rx, chanend c_adat_rx, out port p, chan
     clockFreq[CLOCK_SPDIF_INDEX] = 0;
     clockValid[CLOCK_SPDIF_INDEX] = 0;
     clockInt[CLOCK_SPDIF_INDEX] = 0;
-    clockId[CLOCK_SPDIF_INDEX] = ID_CLKSRC_EXT;
+    clockId[CLOCK_SPDIF_INDEX] = ID_CLKSRC_SPDIF;
 #endif
     clockFreq[CLOCK_INTERNAL_INDEX] = 0;
     clockId[CLOCK_INTERNAL_INDEX] = ID_CLKSRC_INT;
diff --git a/module_usb_audio/devicedefines.h b/module_usb_audio/devicedefines.h
index 13727c32..127bff4a 100644
--- a/module_usb_audio/devicedefines.h
+++ b/module_usb_audio/devicedefines.h
@@ -627,7 +627,6 @@ enum USBEndpointNumber_Out
 #endif
 #endif
 
-
 /* Length of clock unit/clock-selector units */
 #if defined(SPDIF_RX) && defined(ADAT_RX)
 #define NUM_CLOCKS               (3)
@@ -647,7 +646,7 @@ enum USBEndpointNumber_Out
 
 #define ID_CLKSEL                40              /* Clock selector ID */
 #define ID_CLKSRC_INT            41              /* Clock source ID (internal) */
-#define ID_CLKSRC_EXT            42              /* Clock source ID (external) */
+#define ID_CLKSRC_SPDIF          42              /* Clock source ID (external) */
 #define ID_CLKSRC_ADAT           43              /* Clock source ID (external) */
 
 #define ID_XU_MIXSEL             50
diff --git a/module_usb_audio/endpoint0/audiorequests.xc b/module_usb_audio/endpoint0/audiorequests.xc
index 91397836..dda0b2de 100644
--- a/module_usb_audio/endpoint0/audiorequests.xc
+++ b/module_usb_audio/endpoint0/audiorequests.xc
@@ -285,7 +285,7 @@ int AudioClassRequests_2(XUD_ep ep0_out, XUD_ep ep0_in, USB_SetupPacket_t &sp, c
             {
                 /* Clock Unit(s) */
                 case ID_CLKSRC_INT:
-                case ID_CLKSRC_EXT:
+                case ID_CLKSRC_SPDIF:
                 case ID_CLKSRC_ADAT:
                 {
                     /* Check Control selector (CS) */
@@ -345,7 +345,7 @@ int AudioClassRequests_2(XUD_ep ep0_out, XUD_ep ep0_in, USB_SetupPacket_t &sp, c
                             {
                                 switch(unitID)
                                 {
-                                    case ID_CLKSRC_EXT:
+                                    case ID_CLKSRC_SPDIF:
                                     case ID_CLKSRC_ADAT:
 #ifdef REPORT_SPDIF_FREQ
                                         /* Interogate clockgen thread for SPDIF freq */
@@ -393,7 +393,7 @@ int AudioClassRequests_2(XUD_ep ep0_out, XUD_ep ep0_in, USB_SetupPacket_t &sp, c
                                     return XUD_DoGetRequest(ep0_out, ep0_in, buffer, 1, sp.wLength);
                                     break;
 
-                                case ID_CLKSRC_EXT:
+                                case ID_CLKSRC_SPDIF:
 
                                     /* Interogate clockgen thread for validity */
                                     if (!isnull(c_clk_ctl))
@@ -791,7 +791,7 @@ int AudioClassRequests_2(XUD_ep ep0_out, XUD_ep ep0_in, USB_SetupPacket_t &sp, c
             switch( unitID )
             {
                 /* Clock Source Units */
-                case ID_CLKSRC_EXT:
+                case ID_CLKSRC_SPDIF:
                 case ID_CLKSRC_ADAT:
                 case ID_CLKSRC_INT: