本设计可直接用作时钟计数器，同时有调时，定时功能。

Led[3:0]显示秒钟的变化情况。

func用作计时，调时，定时功能转换。

Ledarrive用于提示计时时间已到。

change可使秒钟在数码管显示。

plus键在调时计时时使时钟加一。

shift用于调时计时时分计时与时计时的调整转换。-This design can be used directly as a clock counter, while when adjusted, timing function. Led [3: 0] display changes seconds. func used as the timing, when adjusted, timing function conversion. Ledarrive tips for timing the time has come. change in the digital display allows the second tube. plus key while adjusting the timing when the clock plus one. When adjusted for the shift to adjust the timing when the division timing and the timing of the conversion.