km416s4030.vhd

vhdl cod for ram.For sp3e

            ELSE
                chip_en := false;
            END IF;
        END IF;
    END IF;

    IF (rising_edge(CLKIn) AND CKEreg = '1' AND to_X01(CSNegIn) = '0') THEN
        ASSERT (not(Is_X(DQMLIn)))
            REPORT InstancePath & partID & ": Unusable value for DQML"
            SEVERITY SeverityMode;
        ASSERT (not(Is_X(DQMUIn)))
            REPORT InstancePath & partID & ": Unusable value for DQMU"
            SEVERITY SeverityMode;
        ASSERT (not(Is_X(WENegIn)))
            REPORT InstancePath & partID & ": Unusable value for WENeg"
            SEVERITY SeverityMode;
        ASSERT (not(Is_X(RASNegIn)))
            REPORT InstancePath & partID & ": Unusable value for RASNeg"
            SEVERITY SeverityMode;
        ASSERT (not(Is_X(CASNegIn)))
            REPORT InstancePath & partID & ": Unusable value for CASNeg"
            SEVERITY SeverityMode;

        -- Command Decode
        IF ((RASNegIn = '1') AND (CASNegIn = '1') AND (WENegIn = '1')) THEN
            command := nop;
        ELSIF ((RASNegIn = '0') AND (CASNegIn = '1') AND (WENegIn = '1')) THEN
            command := act;
        ELSIF ((RASNegIn = '1') AND (CASNegIn = '0') AND (WENegIn = '1')) THEN
            command := read;
        ELSIF ((RASNegIn = '1') AND (CASNegIn = '0') AND (WENegIn = '0')) THEN
            command := writ;
        ELSIF ((RASNegIn = '1') AND (CASNegIn = '1') AND (WENegIn = '0')) THEN
            command := bst;
        ELSIF ((RASNegIn = '0') AND (CASNegIn = '1') AND (WENegIn = '0')) THEN
            command := pre;
        ELSIF ((RASNegIn = '0') AND (CASNegIn = '0') AND (WENegIn = '1')) THEN
            command := ref;
        ELSIF ((RASNegIn = '0') AND (CASNegIn = '0') AND (WENegIn = '0')) THEN
            command := mrs;
        END IF;

        -- PowerUp Check
        IF (NOT(PoweredUp) AND command /= nop) THEN
            ASSERT false
                REPORT InstancePath & partID & ": Incorrect power up. Command"
                      & " issued before power up complete."
                SEVERITY SeverityMode;
        END IF;

        -- Bank Decode
        CASE BAIn IS
            WHEN "00" => cur_bank := 0; BankString := " Bank-0 ";
            WHEN "01" => cur_bank := 1; BankString := " Bank-1 ";
            WHEN "10" => cur_bank := 2; BankString := " Bank-2 ";
            WHEN "11" => cur_bank := 3; BankString := " Bank-3 ";
            WHEN others =>
                ASSERT false
                    REPORT InstancePath & partID & ": Could not decode bank"
                           & " selection - results may be incorrect."
                    SEVERITY SeverityMode;
        END CASE;

    END IF;

    -- The Big State Machine
    IF (rising_edge(CLKIn) AND CKEreg = '1') THEN

        ASSERT (not(Is_X(CSNegIn)))
            REPORT InstancePath & partID & ": Unusable value for CSNeg"
            SEVERITY SeverityMode;

        IF (CSNegIn = '1') THEN
            command := nop;
        END IF;

        -- DQM pipeline
        DQMU_reg2 := DQMU_reg1;
        DQML_reg2 := DQML_reg1;
        DQMU_reg1 := DQMU_reg0;
        DQML_reg1 := DQML_reg0;
        DQMU_reg0 := DQMUIn;
        DQML_reg0 := DQMLIn;

        -- by default data drive is Z, might get over written in one
        -- of the passes below
        DataDrive(1) := (OTHERS => 'Z');
        DataDrive(0) := (OTHERS => 'Z');

        banks : FOR bank IN 0 TO hi_bank LOOP
        CASE statebank(bank) IS
            WHEN pwron => 
                ASSERT (DQMLIn = '1' AND DQMUIn = '1')
                    REPORT InstancePath & partID & BankString 
                           &": DQMs must be held high"
                           & " during initialization."
                    SEVERITY SeverityMode;
                IF (PoweredUp = false) THEN
                    ASSERT (command = nop)
                        REPORT InstancePath & partID & BankString
                               &": Only NOPs allowed"
                               & " during power up."
                        SEVERITY SeverityMode;
                    DataDrive(0) := "ZZZZZZZZ";
                    DataDrive(1) := "ZZZZZZZZ";
                ELSIF (command = pre) AND ((cur_bank = bank) OR (AddressIn(10) = '1'))
                                                 THEN
                    statebank(bank) <= precharge, idle AFTER tdevice_TRP;
                END IF;

            WHEN precharge =>
                IF cur_bank = bank THEN
                    -- It is only an error if this bank is selected
                    ASSERT (command = nop OR command = pre)
                        REPORT InstancePath & partID & BankString
                               &": Illegal command received"
                               & " during precharge."
                        SEVERITY SeverityMode;
                END IF;

            WHEN idle =>
                IF (command = nop OR command = bst OR command = pre) OR
                                 (cur_bank /= bank) THEN
                    null;
                ELSIF (command = mrs) THEN
                    IF (statebank = idle & idle & idle & idle) THEN
                        ModeReg := AddressIn;
                        statebank <= mode_set & mode_set & mode_set & mode_set;
                    END IF;
                ELSIF (command = ref) THEN
                    IF (statebank = idle & idle & idle & idle) THEN
                        IF (CKEIn = '1') THEN
                            statebank(bank) <= auto_refresh, idle 
                                 AFTER tdevice_TRCAR;
                        ELSE
                            statebank(bank) <= self_refresh;
                        END IF;
                    END IF;
                ELSIF (command = act) THEN
                    statebank(bank) <= bank_act;
                    ras_in(bank)  <= '1', '0' AFTER 70 ns;
                    rct_in  <= '1', '0' AFTER 1 ns;
                    rcdt_in(bank) <= '1', '0' AFTER 1 ns;
                    MemAddr(bank)(19 downto 8) := AddressIn;  -- latch row addr
                ELSE  -- IF cur_bank = bank THEN
                    ASSERT false
                        REPORT InstancePath & partID & ": Illegal command"
                               & " received in idle state."
                        SEVERITY SeverityMode;
                END IF;

            WHEN mode_set =>
                statebank <= idle & idle & idle & idle;
                ASSERT (ModeReg(7) = '0' AND ModeReg(8) ='0')
                    REPORT InstancePath & partID & BankString
                           &": Illegal operating mode set."
                    SEVERITY SeverityMode;
                ASSERT command = nop
                    REPORT InstancePath & partID & BankString
                           & ": Illegal command received during mode_set."
                    SEVERITY SeverityMode;
                -- read burst length
                IF (ModeReg(2 downto 0) = "000") THEN
                    Burst_Length := 1;
                    Burst_Bits := 0;
                ELSIF (ModeReg(2 downto 0) = "001") THEN
                    Burst_Length := 2;
                    Burst_Bits := 1;
                ELSIF (ModeReg(2 downto 0) = "010") THEN
                    Burst_Length := 4;
                    Burst_Bits := 2;
                ELSIF (ModeReg(2 downto 0) = "011") THEN
                    Burst_Length := 8;
                    Burst_Bits := 3;
                ELSIF (ModeReg(2 downto 0) = "111") THEN
                    Burst_Length := 256;
                    Burst_Bits := 7;
                ELSE
                    ASSERT false
                        REPORT InstancePath & partID & BankString
                               &": Invalid burst length specified."
                        SEVERITY SeverityMode;
                END IF;
                -- read burst type
                IF (ModeReg(3) = '0') THEN
                    Burst := sequential;
                ELSIF (ModeReg(3) = '1') THEN
                    Burst := interleave;
                ELSE
                    ASSERT false
                        REPORT InstancePath & partID & BankString
                               &": Invalid burst type specified."
                        SEVERITY SeverityMode;
                END IF;
                -- read CAS latency
                IF (ModeReg(6 downto 4) = "010") THEN
                    CAS_Lat <= 2;
                ELSIF (ModeReg(6 downto 4) = "011") THEN
                    CAS_Lat <= 3;
                ELSE
                    ASSERT false
                    REPORT InstancePath & partID & BankString &
                        ": CAS Latency set incorrecty "
                    SEVERITY SeverityMode;
                END IF;
                -- read write burst mode
                IF (ModeReg(9) = '0') THEN
                    WB := programmed;
                ELSIF (ModeReg(9) = '1') THEN
                    WB := single;
                ELSE
                    ASSERT false
                        REPORT InstancePath & partID & BankString &
                               ": Invalid burst type specified."
                        SEVERITY SeverityMode;
                END IF;
            WHEN auto_refresh =>
                IF (Ref_Cnt < 4096) THEN
                    Ref_Cnt := Ref_Cnt + 1;
                END IF;
                ASSERT command = nop
                    REPORT InstancePath & partID & BankString &
                           ": Illegal command received during auto_refresh."
                    SEVERITY SeverityMode;

            WHEN bank_act =>
                IF (command = pre) AND ((cur_bank = bank) OR (AddressIn(10) = '1'))
                                               THEN
                    ASSERT ras_out(bank) = '1'
                        REPORT InstancePath & partID & BankString &
                               ": precharge command"
                               & " does not meet tRAS time."
                        SEVERITY SeverityMode;
                        statebank(bank) <= precharge, idle AFTER tdevice_TRP;
                ELSIF (command = nop OR command = bst) OR (cur_bank /= bank) THEN
                    null;
                ELSIF (command = read) THEN
                    ASSERT rcdt_out(bank) = '0'
                        REPORT InstancePath & partID & BankString &
                               ": read command received too soon after active."
                        SEVERITY SeverityMode;
                    ASSERT ((AddressIn(10) = '0') OR (AddressIn(10) = '1'))
                        REPORT InstancePath & partID & BankString &
                               ": AddressIn(10) = X"
                               & " during read command. Next state unknown."
                        SEVERITY SeverityMode;
                    MemAddr(bank)(7 downto 0) := (others => '0');
                                                             -- clr old addr
                    MemAddr(bank)(7 downto Burst_Bits) :=
                              AddressIn(7 downto Burst_Bits); --latch col addr
                    IF (Burst_Bits > 0) THEN
                        Burst_Inc(bank) :=
                                 to_nat(AddressIn(Burst_Bits-1 downto 0));
                    END IF;
                    StartAddr(bank) := Burst_Inc(bank) mod 8;
                    BaseLoc(bank) := to_nat(MemAddr(bank));
                    Location := BaseLoc(bank) + Burst_Inc(bank);
                    IF MemData1(Bank)(Location) = -2 THEN
                        DataDrive(1) := (others => 'U');
                    ELSIF MemData1(Bank)(Location) = -1 THEN
                        DataDrive(1) := (others => 'X');
                    ELSE
                        DataDrive(1) := to_slv(MemData1(Bank)(Location),8);
                    END IF;
                    IF MemData0(Bank)(Location) = -2 THEN
                        DataDrive(0) := (others => 'U');
                    ELSIF MemData0(Bank)(Location) = -1 THEN
                        DataDrive(0) := (others => 'X');
                    ELSE
                        DataDrive(0) := to_slv(MemData0(Bank)(Location),8);
                    END IF;
                    Burst_Cnt(bank) := 1;
                    IF (AddressIn(10) = '0') THEN
                        statebank(bank) <= read;
                    ELSIF (AddressIn(10) = '1') THEN
                        statebank(bank) <= read_auto_pre;
                    END IF;
                ELSIF (command = writ) THEN