在EP2C5T144C8开发板上编的一个VHDL源程序，相当于一个秒表，读数可在4个数码管上显示，通过按键可暂停计数，可继续计数-In EP2C5T144C8 development board this a VHDL source code, the equivalent of a stopwatch, reading on the four digital tube display, can suspend count by buttons, can continue to count