logger, implementation and test

cube/User/Inc/logger.h

@@ -1,6 +1,19 @@
 #ifndef _LOGGER_H_
 #define _LOGGER_H_
 
-void log(char *msg);
+// initialize the logger, creates a ringbuffer
+void logInit();
+
+// de-initialize the logger, free the ringbuffer
+void logFree();
+
+// log a message, make sure it is a null-terminated string
+// return value can be ignored, it is only used in test
+int logMsg(char *msg);
+
+// reads the ringbuffer and transfers data to output channel
+// call this from the idle-loop
+// return value can be ignored, it is only used in test
+int logExecute();
 
 #endif // _LOGGER_H_