F103VBT6是128k的FLASH，在keil设置中设置的是STM32F10X_MD
应该原因在这里，可是这样设置应该没问题吧
- startup_stm32f10x_ld_vl.s: for STM32 Low density Value line devices
- startup_stm32f10x_ld.s: for STM32 Low density devices
- startup_stm32f10x_md_vl.s: for STM32 Medium density Value line devices
- startup_stm32f10x_md.s: for STM32 Medium density devices
- startup_stm32f10x_hd.s: for STM32 High density devices
- startup_stm32f10x_xl.s: for STM32 XL density devices
- startup_stm32f10x_cl.s: for STM32 Connectivity line devices
cl：互联型产品，stm32f105/107系列
vl：超值型产品，stm32f100系列
xl：超高密度产品，stm32f101/103系列
ld：低密度产品，FLASH小于64K
md：中等密度产品，FLASH=64 or 128
hd：高密度产品，FLASH大于128