synth/dsp/boot_rom.vhdl.in
Paul Mathieu 14dba00fd0 Add dsp
With:
- LED control
- UART
- PDM out
- square wave generator (DMA to PDM out (was it really necessary?))
- sample program that plays a square wave from UART values
2021-03-13 15:50:25 -08:00

50 lines
1.1 KiB
VHDL

library ieee;
use ieee.std_logic_1164.all;
use ieee.numeric_std.all;
entity boot_rom is
generic
(
addressWidth : in positive := 16;
busWidth : in positive := 16
);
port
(
clk: in std_logic;
code_addr : in std_logic_vector(15 downto 0);
code_out : out std_logic_vector(15 downto 0);
data_addr : in std_logic_vector(15 downto 0);
data_out : out std_logic_vector(15 downto 0)
);
end boot_rom;
architecture Behavioral of boot_rom is
constant alignment: positive := busWidth / 8;
constant romsize: natural := $nwords;
type romtype is array(0 to romsize - 1) of std_logic_vector(15 downto 0);
signal romdata: romtype := (
$words
);
begin
process(clk) is
variable code_index: natural;
variable data_index: natural;
begin
if rising_edge(clk) then
code_index := to_integer(unsigned(code_addr)) / alignment;
if code_index < romsize then
code_out <= romdata(code_index);
else
code_out <= x"0000";
end if;
data_index := to_integer(unsigned(data_addr)) / alignment;
data_out <= romdata(data_index);
end if;
end process;
end Behavioral;