私は 4 つのプッシュ ボタンを備えた FPGA を持っています。左端の 2 つのボタンは 16 個のレジスタを上下に循環させ、右端の 2 つはこのレジスタに格納されている値を増減させる必要があります。これを行うためのコードでの私の試みは次のとおりです。
entity raminfr is --inferring the RAM here
port (
clk : in std_logic;
we : in std_logic;
a : in unsigned(3 downto 0);
di : in unsigned(7 downto 0);
do : out unsigned(7 downto 0)
);
end raminfr;
architecture rtl of raminfr is
type ram_type is array (0 to 15) of unsigned(7 downto 0);
signal RAM : ram_type;
signal read_a : unsigned(3 downto 0);
begin
U1: entity work.lab1 port map ( --ERROR ON THIS LINE
register_counter => a,
value_counter => di
);
process (clk)
begin
if rising_edge(clk) then
if we = '1' then
RAM(to_integer(a)) <= di;
end if;
read_a <= a;
end if;
end process;
do <= RAM(to_integer(read_a));
end rtl;
--lab1 starts here
library ieee;
use ieee.std_logic_1164.all;
use ieee.numeric_std.all;
entity lab1 is
port(
clock : in std_logic;
key : in std_logic_vector(3 downto 0);
value_counter : out unsigned(7 downto 0) ; --value to be written to register
register_counter : out unsigned(3 downto 0) --register to write value to
);
end lab1;
architecture up_and_down of lab1 is --actual button logic here
begin
process(clock)
begin
if rising_edge(clock) then
if (key(3)='0' and key(2)='0' and key(1)='1' and key(0)='0') then
value_counter <= value_counter + "1";
elsif (key(3)='0' and key(2)='0' and key(1)='0' and key(0)='1') then
value_counter <= value_counter - "1";
elsif (key(3)='1' and key(2)='0' and key(1)='0' and key(0)='0') then
register_counter<= register_counter + "1";
elsif (key(3)='0' and key(2)='1' and key(1)='0' and key(0)='0') then
register_counter<= register_counter - "1";
end if;
end if;
end process;
end architecture up_and_down;
Error (10577): VHDL error at DE2_TOP.vhd(312): actual port "a" of mode "in" cannot be associated with formal port "register_counter" of mode "out"
上記の行でエラーが発生します。これが私がやりたいことをする方法ではないことは明らかです。誰かがこれに光を当てることができますか?