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它显示一个错误: 错误:Xst:787 - “E:/tumama/tytyty.vhd”第54行:索引值< 4>不在范围内数组。通用二进制灰色,灰色二进制转换器,逻辑错误
它是一个“通用”代码,我的嵌入信号A有5位n 我只想用4位来转换一个案例。所以,我有4位Y中 的意见是对的并发代码
,但我不明白 感谢
library IEEE;
use IEEE.STD_LOGIC_1164.ALL;
entity FirstTermExamen is
Generic (n: natural := 4);
Port (Num : in STD_LOGIC_VECTOR (n-1 downto 0);
Sel : in STD_LOGIC;
Y : out STD_LOGIC_VECTOR (n-1 downto 0)
);
end FirstTermExamen;
architecture Behavioral of FirstTermExamen is
signal A: STD_LOGIC_VECTOR (n downto 0);
begin
-- --Secuencial Description
-- Binary_Gray : process(A, Num, Sel)
-- begin
--
-- --Initial conditions
-- A(0) <= Num(0);
-- A(1) <= Num(0) xor Num(1);
--
-- for i in 1 to n-1 loop
-- if Sel = '1' then A(i+1) <= Num(i) xor Num(i+1);
-- else A(i+1) <= A(i) xor Num(i+1);
--
-- end if;
--
-- end loop;
--
-- for j in 0 to n loop
-- Y(j)<= A(j);
--
-- end loop;
--
--end process Binary_Gray;
--Concurrent Description
A(0) <= Num(0);
A(1) <= Num(0) xor Num(1);
Binary_Gray:
for i in 1 to n-1 generate
begin
A(i+1) <= Num(i) xor Num(i+1) when Sel = '1' else
A(i) xor Num(i+1);
end generate;
output:
for j in 0 to n generate
begin
Y(j)<= A(j);
end generate;
end Behavioral;