Re: Repetitive code (Newbie)

"smu" <> wrote in message news:<3f2fd735$0$16171$>...
> I try to find a elegant way to code a component in order to employ it with
> different value of a constant.
> ....
You will have to use generics and for..generate.
Since you are using attributes to specify single rom16x1 component
contents, the solution is not the nicest one:
--------start---------
library IEEE;
use IEEE.STD_LOGIC_1164.ALL;

entity c_nibble is
generic ( busmax : integer := 3;
inits : string := "926C4B5A99CC552A" );
port ( input : in std_logic_vector(3 downto 0);
output : out std_logic_vector(busmax downto 0));
end c_nibble;

architecture c_nibble_a of c_nibble is
component rom16x1
port( a3, a2, a1, a0 : in std_logic;
o : out std_logic);
end component;
attribute init : string;
begin
rom: for i in busmax downto 0 generate
attribute init of blk : label is
inits((busmax-i)*4+1 to (busmax-i)*4+4 );
begin
blk: rom16x1 port map ( a3 => input(3), a2 => input(2), a1 => input(1),
a0 => input(0), o => output(i));
end generate rom;
end c_nibble_a;
-----------stop------------

VHDL 93 compliant compiler is required to handle this code.

Good luck!

Jerry

Jerry

Which would be the nicest solution to initialize the ROM blocks ?

smu

"Jerry" <> a écrit dans le message de news:
...
> "smu" <> wrote in message
news:<3f2fd735$0$16171$>...
> > I try to find a elegant way to code a component in order to employ it
with
> > different value of a constant.
> > ....
> You will have to use generics and for..generate.
> Since you are using attributes to specify single rom16x1 component
> contents, the solution is not the nicest one:
> --------start---------
> library IEEE;
> use IEEE.STD_LOGIC_1164.ALL;
>
> entity c_nibble is
> generic ( busmax : integer := 3;
> inits : string := "926C4B5A99CC552A" );
> port ( input : in std_logic_vector(3 downto 0);
> output : out std_logic_vector(busmax downto 0));
> end c_nibble;
>
> architecture c_nibble_a of c_nibble is
> component rom16x1
> port( a3, a2, a1, a0 : in std_logic;
> o : out std_logic);
> end component;
> attribute init : string;
> begin
> rom: for i in busmax downto 0 generate
> attribute init of blk : label is
> inits((busmax-i)*4+1 to (busmax-i)*4+4 );
> begin
> blk: rom16x1 port map ( a3 => input(3), a2 => input(2), a1 =>
input(1),
> a0 => input(0), o => output(i));
> end generate rom;
> end c_nibble_a;
> -----------stop------------
>
> VHDL 93 compliant compiler is required to handle this code.
>
> Good luck!
>
> Jerry

smu

smu wrote:
> Which would be the nicest solution to initialize the ROM blocks ?
>

This rom has been nice to me:

http://groups.google.com/groups?q=this_rom

-- Mike Treseler

Mike Treseler