超声波测距原码,原来使用外部中断和定时器写的后来把外部中断去掉了-Ultrasonic Ranging original code, the original use of the external interrupt and timer wrote later removed the external interrupt

基于stm32f10x系列的超声波测距，使用超声波模块对物体进行测距(Based on stm32f10xseries of ultrasonic ranging, the ultrasonic module is used to ranging the object)