Library of reusable VHDL components
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90 lines
2.5 KiB

library ieee;
use ieee.std_logic_1164.all;
entity WishBoneSlaveE is
generic (
G_ADR_WIDTH : positive := 8; --* address bus width
G_DATA_WIDTH : positive := 8 --* data bus width
);
port (
--+ wishbone system if
WbRst_i : in std_logic;
WbClk_i : in std_logic;
--+ wishbone inputs
WbCyc_i : in std_logic;
WbStb_i : in std_logic;
WbWe_i : in std_logic;
WbAdr_i : in std_logic_vector(G_ADR_WIDTH-1 downto 0);
WbDat_i : in std_logic_vector(G_DATA_WIDTH-1 downto 0);
--+ wishbone outputs
WbDat_o : out std_logic_vector(G_DATA_WIDTH-1 downto 0);
WbAck_o : out std_logic;
WbErr_o : out std_logic;
--+ local register if
LocalWen_o : out std_logic;
LocalRen_o : out std_logic;
LocalAdress_o : out std_logic_vector(G_ADR_WIDTH-1 downto 0);
LocalData_o : out std_logic_vector(G_DATA_WIDTH-1 downto 0);
LocalData_i : in std_logic_vector(G_DATA_WIDTH-1 downto 0)
);
end entity WishBoneSlaveE;
architecture rtl of WishBoneSlaveE is
type t_wb_slave_fsm is (IDLE, ADDRESS, DATA);
signal s_wb_slave_fsm : t_wb_slave_fsm;
signal s_wb_active : boolean;
begin
WbSlaveControlP : process (WbClk_i) is
begin
if (rising_edge(WbClk_i)) then
if (WbRst_i = '1') then
s_wb_slave_fsm <= IDLE;
else
WbReadC : case s_wb_slave_fsm is
when IDLE =>
s_wb_slave_fsm <= ADDRESS;
when ADDRESS =>
if s_wb_active then
s_wb_slave_fsm <= DATA;
end if;
when DATA =>
s_wb_slave_fsm <= ADDRESS;
when others =>
s_wb_slave_fsm <= IDLE;
end case;
end if;
end if;
end process WbSlaveControlP;
s_wb_active <= true when s_wb_slave_fsm /= IDLE and WbCyc_i = '1' and WbStb_i = '1' else false;
--+ local register if outputs
LocalWen_o <= WbWe_i when s_wb_slave_fsm = DATA and s_wb_active else '0';
LocalRen_o <= not(WbWe_i) when s_wb_slave_fsm = ADDRESS and s_wb_active else '0';
LocalAdress_o <= WbAdr_i when s_wb_slave_fsm /= IDLE and s_wb_active else (others => '0');
LocalData_o <= WbDat_i when s_wb_slave_fsm = DATA and s_wb_active and WbWe_i = '1' else (others => '0');
--+ wishbone if outputs
WbDat_o <= LocalData_i when s_wb_slave_fsm = DATA and WbWe_i = '0' else (others => '0');
WbAck_o <= '1' when s_wb_slave_fsm = DATA else '0';
WbErr_o <= '0';
end architecture rtl;