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library ieee;
use ieee.std_logic_1164.all;
use ieee.numeric_std.all;
entity mdio is port (
clk125 : in std_logic;
reset125 : in std_logic;
command : in std_logic_vector(0 to 27); -- operation(2) & phyaddr(5) & devaddr(5) & data_in(16)
data_out : out std_logic_vector(0 to 15);
enable : in std_logic;
done : out std_logic;
mdio_in : in std_logic;
mdio_out : out std_logic;
mdio_Z : out std_logic;
mdc : out std_logic;
phy_reset_n : out std_logic;
total_count : out std_logic_vector(31 downto 0);
address_count : out std_logic_vector(31 downto 0);
write_count : out std_logic_vector(31 downto 0);
read_count : out std_logic_vector(31 downto 0);
read_incr_count : out std_logic_vector(31 downto 0)
);
end mdio;
architecture arch of mdio is
type state_t is (state_idle, state_preamble, state_start, state_operation,
state_phyaddr, state_devaddr, state_turnaround, state_data);
signal state : state_t;
signal state_count : natural range 0 to 32;
signal operation : std_logic_vector(0 to 1);
signal phyaddr : std_logic_vector(0 to 4);
signal devaddr : std_logic_vector(0 to 4);
signal data_in : std_logic_vector(0 to 15);
signal mdc_count : natural range 0 to 25;
signal mdc_i : std_logic;
signal total_count_i : unsigned(31 downto 0);
signal address_count_i : unsigned(31 downto 0);
signal write_count_i : unsigned(31 downto 0);
signal read_count_i : unsigned(31 downto 0);
signal read_incr_count_i : unsigned(31 downto 0);
signal done_i : std_logic;
begin
phy_reset_n <= not reset125;
mdc <= mdc_i;
operation <= command(0 to 1);
phyaddr <= command(2 to 6);
devaddr <= command(7 to 11);
data_in <= command(12 to 27);
done <= done_i;
process (clk125, reset125) begin
if reset125 = '1' then
mdc_i <= '0';
mdc_count <= 0;
done_i <= '0';
elsif rising_edge(clk125) then
done_i <= '0';
if mdc_count = 25 - 1 then
mdc_count <= 0;
mdc_i <= not mdc_i; -- 2.5 MHz
if mdc_i = '0' then -- rising edge
if state = state_data and state_count = 15 then
done_i <= '1';
end if;
end if;
else
mdc_count <= mdc_count + 1;
end if;
end if;
end process;
process (mdc_i, reset125) begin
if reset125 = '1' then
state <= state_idle;
state_count <= 0;
data_out <= (others => '0');
elsif rising_edge(mdc_i) then
state_count <= state_count + 1;
if state = state_preamble then
if state_count = 31 then
state <= state_start;
state_count <= 0;
end if;
elsif state = state_start then
if state_count = 1 then
state <= state_operation;
state_count <= 0;
end if;
elsif state = state_operation then
if state_count = 1 then
state <= state_phyaddr;
state_count <= 0;
end if;
elsif state = state_phyaddr then
if state_count = 4 then
state <= state_devaddr;
state_count <= 0;
end if;
elsif state = state_devaddr then
if state_count = 4 then
state <= state_turnaround;
state_count <= 0;
end if;
elsif state = state_turnaround then
if state_count = 1 then
state <= state_data;
state_count <= 0;
end if;
elsif state = state_data then
data_out(state_count) <= mdio_in;
if state_count = 15 then
state <= state_idle;
state_count <= 0;
end if;
else -- state = state_idle
if enable = '1' then
state <= state_preamble;
state_count <= 0;
end if;
end if;
end if;
end process;
process (mdc_i, reset125) begin
if reset125 = '1' then
mdio_out <= '0';
mdio_Z <= '1';
elsif falling_edge(mdc_i) then
mdio_out <= '0';
mdio_Z <= '1';
if state = state_preamble then
mdio_out <= '1';
mdio_Z <= '0';
elsif state = state_start then
mdio_out <= '0';
mdio_Z <= '0';
elsif state = state_operation then
mdio_out <= operation(state_count);
mdio_Z <= '0';
elsif state = state_phyaddr then
mdio_out <= phyaddr(state_count);
mdio_Z <= '0';
elsif state = state_devaddr then
mdio_out <= devaddr(state_count);
mdio_Z <= '0';
elsif state = state_turnaround then
if operation(0) = '0' then -- write or address
mdio_Z <= '0';
if state_count = 0 then
mdio_out <= '1';
else
mdio_out <= '0';
end if;
end if;
elsif state = state_data then
if operation(0) = '0' then -- write or address
mdio_Z <= '0';
mdio_out <= data_in(state_count);
end if;
end if;
end if;
end process;
total_count <= std_logic_vector(total_count_i);
address_count <= std_logic_vector(address_count_i);
write_count <= std_logic_vector(write_count_i);
read_count <= std_logic_vector(read_count_i);
read_incr_count <= std_logic_vector(read_incr_count_i);
process (clk125, reset125) begin
if reset125 = '1' then
total_count_i <= (others => '0');
address_count_i <= (others => '0');
write_count_i <= (others => '0');
read_count_i <= (others => '0');
read_incr_count_i <= (others => '0');
elsif rising_edge(clk125) then
if done_i = '1' then
total_count_i <= total_count_i + 1;
if operation = "00" then
address_count_i <= address_count_i + 1;
end if;
if operation = "01" then
write_count_i <= write_count_i + 1;
end if;
if operation = "11" then
read_count_i <= read_count_i + 1;
end if;
if operation = "10" then
read_incr_count_i <= read_incr_count_i + 1;
end if;
end if;
end if;
end process;
end arch;
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