xilinx下使用vhdl编写数字表 具有启动、复位、暂停、暂停后继续计时等功能 能显示的秒计数时间精确到小数点后第二位，即能显示**.**s -xilinx vhdl prepared using digital watch with a start, reset, pause, pause, continue after the timer function can display the seconds counting time accurate to the second