[raggedstone] / dhwk / source / pci / interrupt.vhd

-- J.STELZNER
-- INFORMATIK-3 LABOR
-- 23.08.2006
-- File: INTERRUPT.VHD

library ieee;
use ieee.std_logic_1164.all;

entity INTERRUPT is
        port
        (
                PCI_CLOCK :in std_logic;
                PCI_RSTn :in std_logic; -- PCI reset is asynchron (low active)
                RESET :in std_logic;
                TAST_SETn :in std_logic;
                TAST_RESn :in std_logic;
                INT_IN_0 :in std_logic;
                INT_IN_1 :in std_logic;
                INT_IN_2 :in std_logic;
                INT_IN_3 :in std_logic;
                INT_IN_4 :in std_logic;
                INT_IN_5 :in std_logic;
                INT_IN_6 :in std_logic;
                INT_IN_7 :in std_logic;
                TRDYn :in std_logic; -- event 1 after read of Interrupt status register (low active)
                READ_XX5_4 :in std_logic; -- event 2 after read of Interrupt status register
                INT_RES :in std_logic_vector(7 downto 0); -- clear selected interrupts
                INT_MASKE :in std_logic_vector(7 downto 0); -- interrupt mask register
                INT_REG :out std_logic_vector(7 downto 0); -- interrupt status register
                INTAn :out std_logic; -- second interrupt line for PCI analyzer
                PCI_INTAn :out std_logic -- PCI interrupt line
        );

end entity INTERRUPT;

architecture INTERRUPT_DESIGN of INTERRUPT is

        signal SIG_TAST_Q :std_logic;
        signal SIG_TAST_Qn :std_logic;


        signal SIG_INTA :std_logic;

        signal FF_A :std_logic_vector(7 downto 0);
        signal FF_B :std_logic_vector(7 downto 0);
        signal SET :std_logic_vector(7 downto 0);

        signal SIG_PROPAGATE_INT :std_logic;
        signal SIG_PROPAGATE_INT_SECOND :std_logic;
        signal REG :std_logic_vector(7 downto 0);

begin




 ------------------------------------------------------
        process (PCI_CLOCK)
        begin
                if (PCI_CLOCK'event and PCI_CLOCK ='1') then

 -- THIS IS BROKEN (it cycles the interrupt)
                        SIG_TAST_Q <= not (TAST_SETn and SIG_TAST_Qn);
                        SIG_TAST_Qn <= not (TAST_RESn and SIG_TAST_Q);

                end if;
        end process;

 ------------------------------------------------------

        process (PCI_CLOCK)
        begin
                if (PCI_RSTn = '0') then
                        SET <= "00000000";
                        FF_A <= "00000000";
                        FF_B <= "00000000";

                elsif (rising_edge(PCI_CLOCK)) then
                        if (RESET = '1') then
                                SET <= "00000000";
                                FF_A <= "00000000";
                                FF_B <= "00000000";
                        else
                                FF_A(0) <= INT_IN_0; -- Receive FIFO Empty Flag

                                FF_A(1) <= INT_IN_1; -- Send FIFO Half Full
                                FF_A(2) <= INT_IN_2;
                                FF_A(3) <= INT_IN_3;

                                FF_A(4) <= INT_IN_4;

                                FF_A(5) <= INT_IN_5;
                                FF_A(6) <= INT_IN_6;
                                FF_A(7) <= INT_IN_7;

                                FF_B <= FF_A;

                                SET <= FF_A AND not FF_B;
                        end if;
                end if;
        end process;

        process (PCI_CLOCK,PCI_RSTn)
        begin
                if (PCI_RSTn = '0') then
                        REG <= "00000000";

                elsif(rising_edge(PCI_CLOCK)) then
                        if(RESET = '1') then
                                REG <= "00000000";

                        -- elsif(SIG_TAST_Q = '1') then
                        -- REG <= "00000000" or SET;

                        elsif (TRDYn = '0' AND READ_XX5_4 = '1') then
                                REG <= (REG AND NOT INT_RES) OR SET;
                        else
                                REG <= REG OR SET;
                        end if;
                end if;
        end process;

        SIG_PROPAGATE_INT <= (not TAST_SETn)
        OR (REG(0) AND INT_MASKE(0))
        OR (REG(1) AND INT_MASKE(1))
        OR (REG(2) AND INT_MASKE(2))
        OR (REG(3) AND INT_MASKE(3))
        OR (REG(4) AND INT_MASKE(4))
        OR (REG(5) AND INT_MASKE(5))
        OR (REG(6) AND INT_MASKE(6))
        OR (REG(7) AND INT_MASKE(7));

        process (PCI_CLOCK)
        begin
                if(rising_edge(PCI_CLOCK)) then
                        SIG_PROPAGATE_INT_SECOND <= not SIG_PROPAGATE_INT;
                end if;
        end process;

        INTAn <= not SIG_PROPAGATE_INT_SECOND;
        PCI_INTAn <= '0' when SIG_PROPAGATE_INT_SECOND = '0' else 'Z';
        INT_REG <= REG;

end architecture INTERRUPT_DESIGN;