#define read16() 256*(uint8_t)read_byte() + (uint8_t)read_byte()
#define from16(a, b) 256*a+b
+#define write16(i) { write_byte((uint8_t)i/256); write_byte((uint8_t)i%256); }
uint8_t read_byte(void);
void write_byte(uint8_t b);
void write_apin(uint8_t i, uint8_t a);
uint8_t read_apin(uint8_t i);
+void led_on(uint8_t i);
+void led_off(uint8_t i);
+
long millis(void);
bool input_available(void);
void delay(long ms);