LIBRARY IEEE;
USE IEEE.STD_LOGIC_1164.ALL;
USE IEEE.STD_LOGIC_UNSIGNED.ALL;
ENTITY SINGT IS
PORT ( CLK : IN STD_LOGIC;
DOUT : OUT INTEGER RANGE 255 DOWNTO 0 );
END;
ARCHITECTURE DACC OF SINGT IS
SIGNAL Q : INTEGER RANGE 63 DOWNTO 0 ;
SIGNAL D : INTEGER RANGE 255 DOWNTO 0 ;
BEGIN
PROCESS(CLK)
BEGIN
IF CLK'EVENT AND CLK = '1' THEN
IF Q < 63 THEN Q <= Q + 1; ELSE Q <= 0 ; END IF; END IF;
END PROCESS;
PROCESS(Q)
BEGIN
CASE Q IS
WHEN 00=> D<=255; WHEN 01=> D<=254; WHEN 02=> D<=252; WHEN 03=> D<=249;
WHEN 04=> D<=245; WHEN 05=> D<=239; WHEN 06=> D<=233; WHEN 07=> D<=225;
WHEN 08=> D<=217; WHEN 09=> D<=207; WHEN 10=> D<=197; WHEN 11=> D<=186;
WHEN 12=> D<=174; WHEN 13=> D<=162; WHEN 14=> D<=150; WHEN 15=> D<=137;
WHEN 16=> D<=124; WHEN 17=> D<=112; WHEN 18=> D<= 99; WHEN 19=> D<= 87;
WHEN 20=> D<= 75; WHEN 21=> D<= 64; WHEN 22=> D<= 53; WHEN 23=> D<= 43;
WHEN 24=> D<= 34; WHEN 25=> D<= 26; WHEN 26=> D<= 19; WHEN 27=> D<= 13;
WHEN 28=> D<= 8; WHEN 29=> D<= 4; WHEN 30=> D<= 1; WHEN 31=> D<= 0;
WHEN 32=> D<= 0; WHEN 33=> D<= 1; WHEN 34=> D<= 4; WHEN 35=> D<= 8;
WHEN 36=> D<= 13; WHEN 37=> D<= 19; WHEN 38=> D<= 26; WHEN 39=> D<= 34;
WHEN 40=> D<= 43; WHEN 41=> D<= 53; WHEN 42=> D<= 64; WHEN 43=> D<= 75;
WHEN 44=> D<= 87; WHEN 45=> D<= 99; WHEN 46=> D<=112; WHEN 47=> D<=124;
WHEN 48=> D<=137; WHEN 49=> D<=150; WHEN 50=> D<=162; WHEN 51=> D<=174;
WHEN 52=> D<=186; WHEN 53=> D<=197; WHEN 54=> D<=207; WHEN 55=> D<=217;
WHEN 56=> D<=225; WHEN 57=> D<=233; WHEN 58=> D<=239; WHEN 59=> D<=245;
WHEN 60=> D<=249; WHEN 61=> D<=252; WHEN 62=> D<=254; WHEN 63=> D<=255;
WHEN OTHERS => NULL ;
END CASE; END PROCESS;
DOUT <= D ;
END;
CASE <表达式> IS
When <选择值或标识符> => <顺序语句>; ... ; <顺序语句> ；
When <选择值或标识符> => <顺序语句>; ... ; <顺序语句> ；
...
WHEN OTHERS => <顺序语句>;
END CASE ；
语法规定，是选择值或者标准符。你是两种同用。不行。
谢谢说明:lol
ENTITY AA_Cotrl IS
PORT (
iData : in std_logic_vector(7 DOWNTO 0);
iRs : in std_logic;
iStart : in std_logic;
);
END AA_Cotrl;
signal preStart : std_logic;
合并判读怎么写?
if (preStart & iStart) = "01" then
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