diff --git a/module_usb_audio/main.xc b/module_usb_audio/main.xc
index c74dc503..a95bd01e 100755
--- a/module_usb_audio/main.xc
+++ b/module_usb_audio/main.xc
@@ -92,6 +92,22 @@ on tile[AUDIO_IO_TILE] : buffered in port:32 p_i2s_adc[I2S_WIRES_ADC] =
                 };
 #endif
 
+#if (XUD_SERIES_SUPPORT == XUD_L_SERIES) && (AUDIO_IO_TILE == XUD_TILE)
+/* Note: L series ref clocked clocked from USB clock when USB enabled - use another clockblock for MIDI
+ * if MIDI and XUD on same tile. See XUD documentation. 
+ *
+ * This is a clash with S/PDIF Tx but simultaneous S/PDIF and MIDI not currently supported on single tile device  
+ *     
+ */
+#define CLKBLK_MIDI        XS1_CLKBLK_1;
+#else
+#define CLKBLK_MIDI        XS1_CLKBLK_REF;
+#endif
+#define CLKBLK_SPDIF_TX    XS1_CLKBLK_1
+#define CLKBLK_MCLK        XS1_CLKBLK_2
+#define CLKBLK_I2S_BIT     XS1_CLKBLK_3
+#define CLKBLK_XUD         XS1_CLKBLK_4
+// Currently XUD_U uses 5 also.
 
 #ifndef CODEC_MASTER
 on tile[AUDIO_IO_TILE] : buffered out port:32 p_lrclk       = PORT_I2S_LRCLK;