8位数码管扫描实验.doc

对进入的电压进行分频：LIBRARY IEEE;USE IEEE.STD_LOGIC_1164.ALL;USE IEEE.STD_LOGIC_ARITH.ALL;USE IEEE.STD_LOGIC_UNSIGNED.ALL;ENTITY div_frequency ISPORT(CLK_IN : IN STD_LOGIC; CLK_OUT : OUT STD_LOGIC);END div_frequency;ARCHITECTURE ONE OF div_frequency ISSIGNAL CLK_OUTQ : STD_LOGIC := 0 ; -赋初值仅供仿真使用SIGNAL COUNTQ : STD_LOGIC_VECTOR(23 DOWNTO 0) := 000000000000000000000000;BEGIN PROCESS(CLK_IN)BEGINIF(CLK_INEVENT AND CLK_IN = 1) THEN IF(COUNTQ /= 46000) THEN COUNTQ = COUNTQ + 1;ELSE CLK_OUTQ = NOT CLK_OUTQ; COUNTQ 0);END IF;END IF;END PROCESS;CLK_OUT = CLK_OUTQ;END ARCHITECTURE;- 通过改变COUNTQ /= X , 分频值为 (X+1)*2;数码管显示电路程序：LIBRARY IEEE;USE IEEE.STD_LOGIC_1164.ALL;USE IEEE.STD_LOGIC_UNSIGNED.ALL;ENTITY CounterTube ISPORT(CLK : IN STD_LOGIC; SEG : OUT STD_LOGIC_VECTOR(7 DOWNTO 0); BIT : OUT STD_LOGIC_VECTOR(7 DOWNTO 0);END ENTITY;ARCHITECTURE ONE OF CounterTube IS SIGNAL CNT8 : STD_LOGIC_VECTOR(2 DOWNTO 0);SIGNAL I : INTEGER RANGE 0 TO 15;BEGIN P1: PROCESS(CLK)- 扫描时钟BEGINIF CLKEVENT AND CLK = 1 THEN CNT8 BIT = 11111110 ; I BIT = 11111101 ; I BIT = 11111011 ; I BIT = 11110111 ; I BIT = 11101111 ; I BIT = 11011111 ; I BIT = 10111111 ; I BIT = 01111111 ; I NULL;END CASE;END PROCESS;P3:PROCESS(I)- 译码电路BEGINCASE I ISWHEN 0 = SEG SEG SEG SEG SEG SEG SEG SEG SEG SEG SEG SEG SEG SEG SEG SEG NUL