1用P1或P3口，产生一方波信号，频率为1000Hz，用LCD显示频率和周期

2将输出信号输入到另一端口作频率计的信号输入端，测量此方波信号的频率、周期和脉宽，在另一LCD上将参数值显示出来。

3设置一功能键，能将当前LCD上的信号值锁定

-P1 or port P3, resulting in a party wave signal, a frequency of 1000Hz LCD displays frequency and cycle

2 output signal input for the frequency of the signal input to another port, to measure frequency, period and pulse width of this square wave signal, and another parameter value of the LCD will be displayed.

3 Set a function key, the lock can signal value on the LCD