stm32类型cl、vl、xl、ld、md、hd的含义

- 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