1. 创建工程并设置所选型号的启动文件

选择相对应MCU型号的启动文件： 

* startup_stm32l1xx_md.s: 适用于STM32L Ultra Low Power Medium density devices 

* startup_stm32l1xx_mdp.s:适用于STM32L Ultra Low Power Medium density Plus devices 

* startup_stm32l1xx_hd.s: 适用于STM32L Ultra Low Power High density devices 

* startup_stm32l1xx_xl.s: 适用于STM32L Ultra Low Power XL density devices 

上面四种类型所对应的MCU型号分别是： 

* Ultra Low Power Medium-density devices: - STM32L151x6xx, STM32L151x8xx, STM32L151xBxx, STM32L152x6xx, STM32L152x8xx, STM32L152xBxx, STM32L151x6xxA, STM32L151x8xxA, STM32L151xBxxA, STM32L152x6xxA, STM32L152x8xxA and STM32L152xBxxA, STM32L100x6xx, STM32L100x8xx and STM32L100xBxx 

* Ultra Low Power Medium-density Plus devices: - STM32L151xCxx, STM32L152xCxx and STM32L162xCxx, STM32L100xCxx 

* Ultra Low Power High-density devices: STM32L151xDxx, STM32L152xDxx and STM32L162xDxx 

* Ultra Low Power XL-density devices: STM32L151xExx, STM32L152xExx and STM32L162xExx

2. 根据所选的MCU型号配置固件库

在 stm32l1xx.h (under LibrariesCMSISDeviceSTSTM32L1xxInclude)中配置所选的MCU类型，以及使用的外设头文件。

#if !defined (STM32L1XX_MD) && !defined (STM32L1XX_MDP) && !defined (STM32L1XX_HD) && !defined (STM32L1XX_XL)

    /* #define STM32L1XX_MD  */   /*!< - Ultra Low Power Medium-densitydevices: STM32L151x6xx, STM32L151x8xx,                                                      STM32L151xBxx, STM32L152x6xx, STM32L152x8xx and STM32L152xBxx.                                                  - Ultra Low Power Medium-density Value Line devices: STM32L100x6xx,STM32L100x8xx and STM32L100xBxx.*/

    /* #define STM32L1XX_MDP */   /*!< - Ultra Low Power Medium-density Plus devices: STM32L151xCxx, STM32L152xCxx and STM32L162xCxx

    - Ultra Low Power Medium-density Plus Value Line devices: STM32L100xCxx  */

/* #define STM32L1XX_HD */   /*!< Ultra Low Power High-density devices: STM32L151xDxx, STM32L152xDxx and STM32L162xDxx */

/* #define STM32L1XX_XL */     /*!< Ultra Low Power XL-density devices: STM32L151xExx, STM32L152xExx and STM32L162xExx */

#endif

到这里，对固件库的配置就算完成了，剩下的就是将这些文件包含进编译器中，并对编译器进行相应的配置。