shaomiao.vhd

来自「VHDL电子抢答器的实现。有多个文件」· VHDL 代码 · 共 42 行

LIBRARY IEEE;
USE IEEE.STD_LOGIC_1164.ALL;
USE IEEE.STD_LOGIC_UNSIGNED.ALL;
ENTITY shaomiao IS
PORT(
		CP		:IN STD_LOGIC; 
		SEGOUT	:OUT STD_LOGIC_VECTOR(3 DOWNTO 0);
		SELOUT 	:OUT STD_LOGIC_VECTOR(3 DOWNTO 0);
		d1,d2,d3,d4 :in std_logic_vector(3 downto 0));
END shaomiao;


ARCHITECTURE A OF shaomiao IS

SIGNAL Q :STD_LOGIC_VECTOR(2 DOWNTO 0);

BEGIN

PROCESS(CP)
	BEGIN
		IF CP'EVENT AND CP = '1' THEN 
			Q <= Q+1;
		END IF;
END PROCESS;

--Q start from 1,so it's wrong to shaomiao from 0,
SELOUT   <= "0001"WHEN Q = 1 ELSE
			"0010"WHEN Q = 2 ELSE
			"0100"WHEN Q = 3 ELSE
			"1000"WHEN Q = 4 ELSE
			"0000";

SEGOUT   <= d1 WHEN Q = 1 ELSE
			d2 WHEN Q = 2 ELSE
			d3 WHEN Q = 3 ELSE
			d4 WHEN Q = 4 ELSE
			"1111";

END A;