STM32串口的波特率设置成256000怎么得到的数据不正确??? 设置成115200以下的都可以？？？？

Answer 1

看看你的串口助手是否和单片机设置的波特率一样。
如果一样可能是速度太快导致的，速度越快，串口线越长，误码率越高。

Answer 2

00061 /* Uncomment the line below according to the target STM32 device used in your
00062 application
00063 */
00064
00065 #if !defined (STM32F10X_LD) && !defined (STM32F10X_LD_VL) && !defined (STM32F10X_MD) && !defined (STM32F10X_MD_VL) && !defined (STM32F10X_HD) && !defined (STM32F10X_HD_VL) && !defined (STM32F10X_XL) && !defined (STM32F10X_CL)
00066 /* #define STM32F10X_LD */ /*!< STM32F10X_LD: STM32 Low density devices */
00067 /* #define STM32F10X_LD_VL */ /*!< STM32F10X_LD_VL: STM32 Low density Value Line devices */
00068 /* #define STM32F10X_MD */ /*!< STM32F10X_MD: STM32 Medium density devices */
00069 /* #define STM32F10X_MD_VL */ /*!< STM32F10X_MD_VL: STM32 Medium density Value Line devices */
00070 /* #define STM32F10X_HD */ /*!< STM32F10X_HD: STM32 High density devices */
00071 /* #define STM32F10X_HD_VL */ /*!< STM32F10X_HD_VL: STM32 High density value line devices */
00072 /* #define STM32F10X_XL */ /*!< STM32F10X_XL: STM32 XL-density devices */
00073 /* #define STM32F10X_CL */ /*!< STM32F10X_CL: STM32 Connectivity line devices */
00074 #endif
00075 /* Tip: To avoid modifying this file each time you need to switch between these
00076 devices, you can define the device in your toolchain compiler preprocessor.
看库里面的stm32f10x.h文件，里面很多内容与系统时钟的配置有关。该文件会根据选择的芯片类型来进行时钟配置，要在此位置将选用的芯片类型去掉注释符。当然不想每次修改此文件，比较方便的方法就是在编译器的target options选项框中define
试一下