我有这段代码:
library IEEE;
use IEEE.std_logic_1164.all;
entity Controller is
port (
CLK : in std_logic;
OutENABLE : out std_logic_vector (2 downto 0);
ModuleRESET : in std_logic;
ModuleENABLE : in std_logic
);
end Controller;
architecture Controller_archi of Controller is
signal Counter : integer range 0 to 4200 := 0;
begin
process (CLK, ModuleRESET)
begin
if ModuleRESET = '0' then
OutENABLE <= (others => '0');
Counter <= 0;
elsif rising_edge(CLK) then
if ModuleENABLE = '1' then
Counter <= Counter + 1;
case Counter is
when 0 =>
OutENABLE <= "001";
when 450 =>
OutENABLE <= "010";
when 900 =>
OutENABLE <= "100";
when 1350 =>
OutENABLE <= "001";
Counter <= 0;
when others =>
end case;
else
OutENABLE <= "000";
end if;
end if;
end process;
end Controller_archi;
但它不像我需要的那样工作。
我需要什么:
- 当
ModuleENABLE
立即变为"1"时OutENABLE
变为"001"而不是一开始rising_edge(CLK)
(现在,在此代码中,如果 ModuleENABLE 变为"1",OutENABLE 不会从"000"更改为"001",它会在第一个 rising_edge(CLK))后更改为"001") - 计数器在
rising_edge(CLK)
时上升,OutENABLE
每CLK
事件更新一次。(现在,在此代码中,计数器在rising_edge(CLK)时上升,但OutENABLE在rising_edge(CLK)时更新,而不是在CLK上升和下降时更新)
所以我修改了代码来做到这一点:
library IEEE;
use IEEE.std_logic_1164.all;
entity Controller is
port (
CLK : in std_logic;
OutENABLE : out std_logic_vector (2 downto 0);
ModuleRESET : in std_logic;
ModuleENABLE : in std_logic
);
end Controller;
architecture Controller_archi of Controller is
signal Counter : integer range 0 to 4200 := 0;
begin
process (CLK, ModuleENABLE, ModuleRESET)
begin
if ModuleRESET = '0' then
OutENABLE <= (others => '0');
Counter <= 0;
elsif ModuleENABLE = '1' then
if rising_edge(CLK) then
Counter <= Counter + 1;
end if;
case Counter is
when 0 =>
OutENABLE <= "001";
when 450 =>
OutENABLE <= "010";
when 900 =>
OutENABLE <= "100";
when 1350 =>
OutENABLE <= "001";
Counter <= 0;
when others =>
end case;
else
Counter <= 0;
OutENABLE <= "000";
end if;
end process;
end Controller_archi;
现在代码的工作方式就像我在ModelSim中需要的那样,但是当我合成或编译它并再次模拟时,它不起作用。
我的问题是:
第二代码有什么问题,我该如何解决?
如果我无法修复第二个代码,我如何修改第一个代码以根据需要工作?
第二代码有什么问题,我该如何解决?
您的合成工具对时钟和复位线的连接方式很挑剔。您必须使用如下结构:
if ModuleRESET = '0' then
...
elsif rising_edge(CLK) then
或者合成工具无法识别时钟和复位线。
如果我无法修复第二个代码,我如何修改第一个代码以根据需要工作?
您需要将"OutENABLE"移到第一个进程之外,并进入它自己的进程。从你所说的,OutENABLE 不应该是一个寄存器 - 它应该是 Counter、ModuleRESET 和 ModuleENABLE 的组合函数。试试这个。
process (CLK, ModuleRESET)
begin
if ModuleRESET = '0' then
Counter <= 0;
elsif rising_edge(CLK) then
if ModuleENABLE = '1' then
Counter <= Counter + 1;
case Counter is
when 1350 =>
Counter <= 0;
when others =>
null;
end case;
end if;
end if;
end process;
process (Counter, ModuleRESET, ModuleEnable)
begin
OutENABLE <= "000";
if ModuleRESET = '1' and ModuleENABLE = '1' then
case Counter is
when 0 .. 449 =>
OutENABLE <= "001";
when 450 .. 899 =>
OutENABLE <= "010";
when 900 .. 1349 =>
OutENABLE <= "100";
when others =>
OutENABLE <= "001";
end case;
end if;
end process;