Lots of development of new features. Radio input, motor output, PID control

loops, boot-time initialisation, option to run without attached UART.

And.. it flies!

uart.h

@@ -3,6 +3,7 @@
 
 #include "types.h"
 
+#ifdef USE_UART
 void init_uart(void);
 void putch(char c);
 void putstr(char *s);
@@ -10,5 +11,14 @@ void putint(unsigned int n);
 void putint_s(int n);
 void puthex(unsigned int n);
 bool getch(char *c);
+#else
+#define init_uart() ((void)0)
+#define putch(x) ((void)0)
+#define putstr(x) ((void)0)
+#define putint(x) ((void)0)
+#define putint_s(x) ((void)0)
+#define puthex(x) ((void)0)
+#define getch(x) (FALSE)
+#endif
 
 #endif /* __UART_H */