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2051e520
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Arnaud Dieumegard
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library ieee;
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use ieee.std_logic_1164.all;
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library ieee;
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use ieee.numeric_std.all;
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entity output_split7 is
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port (
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wa0_data : in std_logic_vector(7 downto 0);
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wa0_addr : in std_logic_vector(2 downto 0);
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ra0_data : out std_logic_vector(7 downto 0);
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ra0_addr : in std_logic_vector(2 downto 0);
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wa0_en : in std_logic;
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clk : in std_logic
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);
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end output_split7;
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architecture augh of output_split7 is
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-- Embedded RAM
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type ram_type is array (0 to 7) of std_logic_vector(7 downto 0);
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signal ram : ram_type := (others => (others => '0'));
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-- Little utility functions to make VHDL syntactically correct
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-- with the syntax to_integer(unsigned(vector)) when 'vector' is a std_logic.
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-- This happens when accessing arrays with <= 2 cells, for example.
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function to_integer(B: std_logic) return integer is
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variable V: std_logic_vector(0 to 0);
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begin
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V(0) := B;
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return to_integer(unsigned(V));
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end;
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function to_integer(V: std_logic_vector) return integer is
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begin
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return to_integer(unsigned(V));
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end;
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begin
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-- Sequential process
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-- It handles the Writes
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process (clk)
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begin
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if rising_edge(clk) then
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-- Write to the RAM
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-- Note: there should be only one port.
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if wa0_en = '1' then
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ram( to_integer(wa0_addr) ) <= wa0_data;
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end if;
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end if;
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end process;
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-- The Read side (the outputs)
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ra0_data <= ram( to_integer(ra0_addr) );
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end architecture;
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