+// debug
+// 0 - no debug messages 1 - error messages 2 - all messages 4 - extended debug mode
+#define MF_DBG_NONE 0
+#define MF_DBG_ERROR 1
+#define MF_DBG_ALL 2
+#define MF_DBG_EXTENDED 4
+extern int MF_DBGLEVEL;
+
+// reader voltage field detector
+#define MF_MINFIELDV 4000
+
+#ifndef MIN
+# define MIN(a, b) (((a) < (b)) ? (a) : (b))
+#endif
+
+#ifndef MAX
+# define MAX(a, b) (((a) > (b)) ? (a) : (b))