很全很齐的有关超声波测距的资料 包括PIC的 51的测试程序 以数码管 1602 12864为显示方式的程序-All very neat about a ultrasonic ranging material including PIC of the test program to 51 1602 12864 for digital tube showing the way program

51单片机超声波测距程序，包括报警电路，及1602的显示程序-51 single ultrasonic ranging program, including alarm circuits, and the 1602 display program