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在Keil MDK 开发环境里，比如一个 无符号32位整形数据会有很多种表示方法：
1 unsigned int 32 （C语言标准表达方法）
2 uint32_t ;
3 u32;

这三种方式都是在表达同一个意思，可为什么ST的开发人员要搞的这么乱呢？

其实ST 搞这么多花样，无非是想开发人员在写代码时定义数据类型能少写几个符号，然后又因为前后版本升级，为了兼容旧版本（主要是V2.0）才会出现这么多表示方法。不管他怎么换，都是基于标准C来的，看清楚以下几个文件你就OK了：core_cm3.h ；stm32f10x.h; stdint.h; 其中每个文件大概作用如下：

stdint.h 这里放着C语言的标准表达方式

//第36行开始
    typedef   signed          char int8_t;  //  标准表达方式 signed char 被等同于 int8_t；
    typedef   signed short     int int16_t;
    typedef   signed           int int32_t;//在32位环境里，int代表4个字节32位！！
    typedef   signed       __int64 int64_t;
 
    typedef unsigned          char uint8_t;
    typedef unsigned short     int uint16_t;
    typedef unsigned           int uint32_t;
    typedef unsigned       __int64 uint64_t;
    
    typedef   signed          char int_least8_t;
    typedef   signed short     int int_least16_t;
    typedef   signed           int int_least32_t;
    typedef   signed       __int64 int_least64_t;
      
    typedef unsigned          char uint_least8_t;
    typedef unsigned short     int uint_least16_t;
    typedef unsigned           int uint_least32_t;
    typedef unsigned       __int64 uint_least64_t;
    
    typedef   signed           int int_fast8_t;
    typedef   signed           int int_fast16_t;
    typedef   signed           int int_fast32_t;
    typedef   signed       __int64 int_fast64_t;
    
   typedef unsigned           int uint_fast8_t;
    typedef unsigned           int uint_fast16_t;
    typedef unsigned           int uint_fast32_t;
    typedef unsigned       __int64 uint_fast64_t;
    
    typedef   signed           int intptr_t;
    typedef unsigned           int uintptr_t;
 
    typedef   signed       __int64 intmax_t;
    typedef unsigned       __int64 uintmax_t;

core_cm3.h 文件主要针对动态 静态 变量修饰符做出类型扩展

#ifdef __cplusplus
      #define   __I     volatile            
    #else
      #define   __I     volatile const      
    #endif
    #define     __O     volatile            
    #define     __IO    volatile

 stm32f10x.h 这个文件主要是为了兼容旧版本吧

    typedef int32_t  s32;
    typedef int16_t s16;
    typedef int8_t  s8;
    
    typedef const int32_t sc32; 
    typedef const int16_t sc16; 
    typedef const int8_t sc8;  
    
    typedef __IO int32_t  vs32;
    typedef __IO int16_t  vs16;
    typedef __IO int8_t   vs8;
    
    typedef __I int32_t vsc32; 
    typedef __I int16_t vsc16; 
    typedef __I int8_t vsc8;  
    
    typedef uint32_t  u32;
    typedef uint16_t u16;
    typedef uint8_t  u8;
    
    typedef const uint32_t uc32; 
    typedef const uint16_t uc16; 
    typedef const uint8_t uc8;  
    
    typedef __IO uint32_t  vu32;
    typedef __IO uint16_t vu16;
    typedef __IO uint8_t  vu8;
    
    typedef __I uint32_t vuc32; 
    typedef __I uint16_t vuc16; 
    typedef __I uint8_t vuc8;