这个是51芯片的频率计，用C语言写的，非常简单-This is the chip frequency counter 51, written in C language and very simple

这个是51单片机的自行车测速程序，是用C语言写的，其实就是一个频率计-This is the 51 single speed bike program is written in C language, in fact, a frequency counter

数字频率计，这是个很常用的简单的51小程序，测量的频率范围不清楚，大家自己测-Digital frequency meter, which is a very common 51 small procedures, the frequency range of the measurement is not clear, we test