diff -r b74b0e4902c3 -r ad2c8b13eb88 main/calibration.c
--- a/main/calibration.c	Sat Oct 20 13:23:15 2018 +0200
+++ b/main/calibration.c	Sat Oct 20 17:09:48 2018 +0200
@@ -9,14 +9,14 @@
 static const char		*TAG = "calibration";
 
 
-extern uint16_t                 tp_xleft;
-extern uint16_t                 tp_xright;
-extern uint16_t                 tp_ytop;
-extern uint16_t                 tp_ybottom;
+extern uint16_t                 tp_xleft;		///< Testpoint X left
+extern uint16_t                 tp_xright;		///< Testpoint X right
+extern uint16_t                 tp_ytop;		///< Testpoint Y top
+extern uint16_t                 tp_ybottom;		///< Testpoint Y bottom
 
 
 // Distance of the testpoints from the corders.
-#define	CAL_DISTANCE		15
+#define	CAL_DISTANCE		15			///< Testpoint size
 
 
 int TS_set_calibration(int xleft, int xright, int ytop, int ybottom)