diff --git a/src/cw/lw.h b/src/cw/lw.h
index 1f7f1164..595cea92 100644
--- a/src/cw/lw.h
+++ b/src/cw/lw.h
@@ -6,13 +6,35 @@
  * @{
  */
 
-
+/**
+ * Put a byte to to an output buffer 
+ *
+ * @param dst destination buffer
+ * @param b byte to put
+ * @return 1 (number of bytes put)
+ */
 #define lw_put_byte(dst,b) \
 	(*(dst)=b,1)
 
+/**
+ * Put a word to to an output buffer. The word
+ * is converted to network byte order.
+ *
+ * @param dst destination buffer
+ * @param w word to put
+ * @return 2 (number of bytes put)
+ */
 #define lw_put_word(dst,w)\
 	(*((uint16_t*)(dst)) = htons(w),2)
 
+/**
+ * Put a dword to to an output buffer. The dword
+ * is converted to network byte order.
+ *
+ * @param dst destination buffer
+ * @param dw dword to put
+ * @return 4 (number of bytes put)
+ */
 #define lw_put_dword(dst,dw)\
 	(*((uint32_t*)(dst)) = htonl(dw),4)