基于Spartan-3e的数码管显示时钟程序的设计，整个流程讲解详细。-A very important concept in digital design is that of the clock. A clock is used to synchronize systems in digital logic, and provides a convenient way to keep track of real time. Another equally important fact is the ability to translate information to a human readable form. In our case, the peripheral module seven segment display device PmodSSD　will be used.　The Digilent Spartan 3E Starter board　has a 50 MHz oscillator that is used creatively to obtain other useful clock frequencies.