diff --git a/core/dev/cc2420_const.h b/core/dev/cc2420_const.h
index 0f20ef083..0e0a4dbc6 100644
--- a/core/dev/cc2420_const.h
+++ b/core/dev/cc2420_const.h
@@ -28,11 +28,19 @@
  *
  */
 
-/* @(#)$Id: cc2420_const.h,v 1.1 2006/06/17 22:41:16 adamdunkels Exp $ */
+/* @(#)$Id: cc2420_const.h,v 1.2 2007/01/12 18:18:23 bg- Exp $ */
 
 #ifndef CC2420_CONST_H
 #define CC2420_CONST_H
 
+/*
+ * All constants are from the Chipcon CC2420 Data Sheet that at one
+ * point in time could be found at
+ * http://www.chipcon.com/files/CC2420_Data_Sheet_1_4.pdf
+ *
+ * The page numbers below refer to pages in this document.
+ */
+
 /* Page 27. */
 enum cc2420_status_byte {
   CC2420_XOSC16M_STABLE = 6,