资源中包含C51源代码、proteus仿真图以及编译好的hex文件

利用AT89C51单片机结合字符型LCD显示器设计的一个简易的倒数计数器，可用来煮方便面、煮开水或小睡片刻等。做一小段时间倒计数，当倒计数为0时，则发出一段音乐声响，通知倒计数终了，该做应当做的事。

定时闹钟的基本功能如下。

字符型LCD（16 ′ 2）显示器。

显示格式为“TIME 分分:秒秒”。

用4个按键操作来设置当前想要倒计数的时间。一旦按下键则开始倒计数，当计数为0时，发出一阵音乐声。

程序执行后工作指示灯LED闪动，表示程序开始执行，按下操作键K1～K4动作如下。

K1—可调整倒计数的时间1～60分钟。

K2—设置倒计数的时间为5分钟，显示“0500”。

K3—设置倒计数的时间为10分钟，显示“1000”。

K4—设置倒计数的时间为20分钟，显示“2000”。-Resources include C51 source code, proteus simulation map and compiled hex file

AT89C51 microcontroller combined with character LCD display design of a simple countdown counter, can be used to cook instant noodles, boiled water or nap, etc.. Do a short time countdown, when the countdown count is 0, then issued a piece of music sound, notify count count end, do what should be done.

The basic functions of timing alarm clock are as follows.

The character of LCD (16 2) display.

Display format　TIME minutes: seconds seconds .

With 4 buttons to set the current time to count down. Once the key is pressed, it begins to count down. When the count is 0, a burst of music.

Procedures after the implementation of the work indicator LED flashing, said the program began to perform, press the operating key K1 ~ K4 action as follows.

K1- adjustable count countdown time 1 ~ 60 minutes.

K2- set counter count time for 5 minutes, show　0500 .

K3- set counter count time for 10 minutes, show　1000 .