基于AVR Atmega88的超声波测距程序，探测距离2cm-483cm，误差0.3cm-Ultrasonic Ranging Based on AVR Atmega88 procedures, detection distance 2cm-483cm, 0.3cm error

超声波探测程序，可同时接6路超声波，只开一个定时器-Ultrasonic detection program, at the same time the ultrasonic 6 road, only a timer