LCD 1602的响应速度相对于单片机的速度来说是偏慢的。

举个简单的例子，把一桶油通过漏斗向一个瓶子里倒，倒油的速度，即流量必须维持在一定范围之内，倒得太快油会从漏斗顶部溢出来，这样就浪费掉了。我们通过眼睛可以判断并使油面保持在顶面以下，以漏斗的额定流量来倒油，这样效率最高。

而对于单片机来说，1602好比那个瓶子漏斗，写入1602中要显示的数据好比油，如果以单片机的高运行速度向1602写数据就很可能造成上面所说的溢出，比如连续写入abc，结果只显示出了a，这是因为1602的显示芯片每次都要花时间来处理输入的ascii码数据，并把它显示出来。而我们却不容易主动地去控制写入数据的速度，所以1602使用忙信号就有必要了，每次单片机只有检测到忙信号为0，即不忙时，才向1602发数据。比如要显示abc,则这样操作，写a---判忙---写b---判忙---写c---判忙。这样就不会出错了。

这几年推出的lcd,像手机的屏响应速度就比较快，而1602这个古董我用示波器测过，大约40us左右的忙处理时间，而很多速度快的单片机的指令周期都是ns级的。也就是说单片机相当一段时间都在‘等’LCD。

-LCD 1602 response speed relative to it is partial of single chip speed slow.

Give a simple example, put a barrels of oil to a bottle through a funnel, pour oil poured the speed of flow must maintain, namely, in certain limits, fall so fast oil spill from funnel top, thus wasting away. We can judge and through the eyes in the top surface oil noodles keep under the rated flow to funnel to pour oil, such efficiency is the highest.

And for single-chip microcomputer, it is like that bottle funnel 1602 show, write 1602 data like oil, if the high speed on single to write the data may be 1602 caused by the spill, such as said above, the results only for writing ABC showed a, this is because the display chip 1602 every time you want to take the time to deal with the input ASCII data, and it is displayed. But we are not easy to write data to voluntarily control the speed, so 1602 use busy signal is necessary, each only detect busy signal microcontroller is zero, that is not favour, just to s