diff --git a/lib_xua/src/core/pdm_mics/mic_array_conf.h b/lib_xua/src/core/pdm_mics/mic_array_conf.h
index 81e062b4..e88cdbb6 100644
--- a/lib_xua/src/core/pdm_mics/mic_array_conf.h
+++ b/lib_xua/src/core/pdm_mics/mic_array_conf.h
@@ -8,6 +8,13 @@
 #define MIC_ARRAY_FRAME_SIZE (XUA_MIC_FRAME_SIZE)
 #endif
 
+// The default definition of MIC_ARRAY_MAX_FRAME_SIZE_LOG2 must appear in this file
+//   because an assembler file #includes it.
+// The assembler does not understand C language syntax, only C pre-processor syntax.
+#ifndef MIC_ARRAY_MAX_FRAME_SIZE_LOG2
+#define MIC_ARRAY_MAX_FRAME_SIZE_LOG2 (0)
+#endif
+
 #ifndef MIC_ARRAY_NUM_MICS
 #define MIC_ARRAY_NUM_MICS (XUA_NUM_PDM_MICS)
 #endif