用宏实现HEX到ASCII ，ASCII 到HEX

#define HEX2ASCII(value, data)  do{              value = (value > 0x09)?(value+0x7):value;            *data = value + 0x30;           }while(0)

#define ASCII2HEX(value, data)  do{              value = *data;            value = (value > 0x40)?(value - 0x7):value;           }while(0)