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)

用宏实现HEX到ASCII ，ASCII 到HEX

原文：http://www.cnblogs.com/chengliangsheng/p/4324391.html