//stm32f10x.h文件内定义
typedef uint32_t u32;
typedef uint16_t u16;
typedef uint8_t u8;
//无符号
typedef int32_t s32;
typedef int16_t s16;
typedef int8_t s8;
//有符号
/* exact-width unsigned integer types */
typedef unsigned char uint8_t;
typedef unsigned short int uint16_t;
typedef unsigned int uint32_t;
typedef unsigned __INT64 uint64_t;
即unsigned char --> uint8_t --> u8 所以在MDK中定义为u8 u16 u32 的即为 "无符号字符型","无符号短整形","无符号长整形"
其他类型的定义查找方法相同,进入定义看即可.