#define B0 (1<<0)
#define B1 (1<<1)
#define B2 (1<<2)
#define B3 (1<<3)
#define B4 (1<<4)
#define B5 (1<<5)
#define B6 (1<<6)
#define B7 (1<<7)
#define biton(port,bit) ((port & bit) != 0)