You cannot select more than 25 topics
Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
78 lines
2.1 KiB
VHDL
78 lines
2.1 KiB
VHDL
library ieee;
|
|
use ieee.std_logic_1164.all;
|
|
use ieee.numeric_std.all;
|
|
use std.textio.all;
|
|
|
|
library work;
|
|
use work.wishbone_types.all;
|
|
use work.simple_ram_behavioural_helpers.all;
|
|
|
|
entity simple_ram_behavioural is
|
|
generic (
|
|
FILENAME : string;
|
|
SIZE : integer
|
|
);
|
|
|
|
port (
|
|
clk : in std_ulogic;
|
|
rst : in std_ulogic;
|
|
|
|
wishbone_in : in wishbone_master_out;
|
|
wishbone_out : out wishbone_slave_out
|
|
);
|
|
end simple_ram_behavioural;
|
|
|
|
architecture behave of simple_ram_behavioural is
|
|
type wishbone_state_t is (IDLE, ACK);
|
|
|
|
signal state : wishbone_state_t := IDLE;
|
|
signal ret_ack : std_ulogic := '0';
|
|
signal identifier : integer := behavioural_initialize(filename => FILENAME, size => SIZE);
|
|
signal reload : integer := 0;
|
|
begin
|
|
wishbone_process: process(clk)
|
|
variable ret_dat: std_ulogic_vector(63 downto 0) := (others => '0');
|
|
begin
|
|
wishbone_out.ack <= ret_ack and wishbone_in.cyc and wishbone_in.stb;
|
|
wishbone_out.dat <= ret_dat;
|
|
|
|
if rising_edge(clk) then
|
|
if rst = '1' then
|
|
state <= IDLE;
|
|
ret_ack <= '0';
|
|
else
|
|
ret_dat := x"FFFFFFFFFFFFFFFF";
|
|
|
|
-- Active
|
|
if wishbone_in.cyc = '1' then
|
|
case state is
|
|
when IDLE =>
|
|
if wishbone_in.stb = '1' then
|
|
-- write
|
|
if wishbone_in.we = '1' then
|
|
assert not(is_x(wishbone_in.dat)) and not(is_x(wishbone_in.adr)) severity failure;
|
|
report "RAM writing " & to_hstring(wishbone_in.dat) & " to " & to_hstring(wishbone_in.adr);
|
|
behavioural_write(wishbone_in.dat, wishbone_in.adr, to_integer(unsigned(wishbone_in.sel)), identifier);
|
|
reload <= reload + 1;
|
|
ret_ack <= '1';
|
|
state <= ACK;
|
|
else
|
|
behavioural_read(ret_dat, wishbone_in.adr, to_integer(unsigned(wishbone_in.sel)), identifier, reload);
|
|
report "RAM reading from " & to_hstring(wishbone_in.adr) & " returns " & to_hstring(ret_dat);
|
|
ret_ack <= '1';
|
|
state <= ACK;
|
|
end if;
|
|
end if;
|
|
when ACK =>
|
|
ret_ack <= '0';
|
|
state <= IDLE;
|
|
end case;
|
|
else
|
|
ret_ack <= '0';
|
|
state <= IDLE;
|
|
end if;
|
|
end if;
|
|
end if;
|
|
end process;
|
|
end behave;
|