[英]VHDL - Writing to FPGA Register
我有一个带有四个按钮的FPGA-最左边的两个按钮应在16个寄存器之间循环,而最右边的两个按钮应使该寄存器中存储的值递增或递减。 这是我尝试执行此操作的代码:
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;
我收到错误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"
上述行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"
。 显然,这不是我要做自己想做的事情。 有人可以阐明这一点吗?
改变您的观点:将RAM放在Pushbutton-FSM下。 反之亦然。
该RAM描述应该是可综合的。 如果没有,请查看您的工具供应商的综合指南。
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 entity raminfr;
architecture rtl of raminfr is
type ram_type is array (0 to 15) of unsigned(7 downto 0);
signal RAM : ram_type;
begin
process (clk)
begin
if rising_edge(clk) then
if we = '1' then
RAM(to_integer(a)) <= di;
end if;
do <= RAM(to_integer(a));
end if;
end process;
end architecture rtl;
您还忘记了激活RAM的写使能。 也许您可以尝试以下代码(始终首先进行模拟!):
--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
ram_data : out unsigned(7 downto 0); --value from 'RAM-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
signal value : unsigned(7 downto 0) := (others => '0');
signal ram_a : unsigned(3 downto 0) := (others => '0');
signal ram_we : std_logic;
begin
-- infer your RAM
your_ram: entity work.raminfr
port map (
clk => clock, --: in std_logic;
we => ram_we, --: in std_logic;
a => ram_a, --: in unsigned(3 downto 0);
di => value, --: in unsigned(7 downto 0);
do => ram_data --: out unsigned(7 downto 0)
);
process(clock)
begin
if rising_edge(clock) then
-- default
ram_we <= '0';
-- change value
if key(1) = '1' then
value <= value + 1;
end if;
-- change value
if key(0) = '1' then
value <= value - 1;
end if;
-- change 'register'
if key(3) = '1' then
ram_a <= ram_a + 1;
end if;
-- write value to register
if key(2) = '1' then
ram_we <= '1';
end if;
end if;
end process;
value_counter <= value;
register_counter <= ram_a;
end architecture up_and_down;
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