c51单片机 rlc f通过555定时器测量，有选择通道，并且使用数码管显示四个按键 可以选择计算测量的值 通过中断实现频率计数，本人呕血编程-rlc f by 555 timer measurement, select a channel, digital display and four buttons can choose to calculate the value of the measurement through the interrupt frequency count, I hematemesis programming. . .