end if; end process; u5:process(clk1k)----八段数码管选通输出 variable temp:integer range 0 to 3; begin if(clk1k'event and clk1k='1')then case temp is when 0=>num<=num1;temp:=1;sel<="111101"; when 1=>num<=num2;temp:=2;sel<="111110"; when 2=>num<=num3;temp:=3;sel<="110111"; when 3=>num<=num4;temp:=0;sel<="111011"; end case; end if; end process; end;
-------选用 4 个数码管输出倒计时
八 总体电路图及管角分布QUARTUS 实体图