mt48lc32m8a2.vhd

vhdl cod for ram.For sp3e

                  IF cur_bank = bank THEN
                    MemAddr(bank)(9 downto 0) := (others => '0');
                                                             -- clr old addr
                    MemAddr(bank)(9 downto Burst_Bits) :=
                              AddressIn(9 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 MemData(Bank)(Location) = -2 THEN
                        DataDrive := (others => 'U');
                    ELSIF MemData(Bank)(Location) = -1 THEN
                        DataDrive := (others => 'X');
                    ELSE
                        DataDrive := to_slv(MemData(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;
                  ELSE
                    statebank(bank) <= bank_act;
                  END IF;
                ELSIF (command = writ) THEN
                  IF cur_bank = bank THEN
                    ASSERT rcdt_out(bank) = '0'
                        REPORT InstancePath & partID & BankString &
                               ": write command"
                               & " received too soon after active."
                        SEVERITY SeverityMode;
                    ASSERT ((AddressIn(10) = '0') OR (AddressIn(10) = '1'))
                        REPORT InstancePath & partID & BankString &
                               ": AddressIn(10) = X"
                               & " during write command. Next state unknown."
                        SEVERITY SeverityMode;
                    MemAddr(bank)(9 downto 0) := (others => '0');
                                                             -- clr old addr
                    MemAddr(bank)(9 downto Burst_Bits) :=
                              AddressIn(9 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 (DQM_nwv = '0') THEN
                        IF Violation = '0' THEN
                            MemData(Bank)(Location) :=
                            to_nat(DataIn(7 downto 0));
                        ELSE
                            MemData(Bank)(Location) := -1;
                        END IF;
                    END IF;
                    Burst_Cnt(bank) := 1;
                    wrt_in <= '1';
                    IF (AddressIn(10) = '0') THEN
                        statebank(bank) <= write;
                    ELSIF (AddressIn(10) = '1') THEN
                        statebank(bank) <= write_auto_pre;
                    END IF;
                  ELSE
                    statebank(bank) <= bank_act;
                  END IF;
                ELSIF (command = pre) AND ((cur_bank = bank) OR
                (AddressIn(10) = '1')) THEN
                    statebank(bank) <= precharge, idle AFTER tdevice_TRP;
                    ASSERT ras_out(bank) = '1'
                        REPORT InstancePath & partID & BankString &
                           ": precharge command"
                               & " does not meet tRAS time."
                        SEVERITY SeverityMode;
                ELSIF (command = nop) OR (cur_bank /= bank) THEN
                    IF (Burst_Cnt(bank) = Burst_Length) THEN
                        statebank(bank) <= bank_act;
                        Burst_Cnt(bank) := 0;
                        ras_in(bank) <= '1';
                    ELSE
                        IF (Burst = sequential) THEN
                            Burst_Inc(bank) := (Burst_Inc(bank) + 1) MOD
                                                Burst_Length;
                        ELSE
                            Burst_Inc(bank) := intab(StartAddr(bank))
                                                    (Burst_Cnt(bank));
                        END IF;
                        Location := BaseLoc(bank) + Burst_Inc(bank);
                        IF MemData(Bank)(Location) = -2 THEN
                            DataDrive := (others => 'U');
                        ELSIF MemData(Bank)(Location) = -1 THEN
                            DataDrive := (others => 'X');
                        ELSE
                            DataDrive := to_slv(MemData(Bank)(Location),8);
                        END IF;
                        Burst_Cnt(bank) := Burst_Cnt(bank) + 1;
                    END IF;
                ELSIF cur_bank = bank THEN
                    ASSERT false
                        REPORT InstancePath & partID & BankString &
                               ": Illegal command"
                               & " received in read state."
                        SEVERITY SeverityMode;
                END IF;

            WHEN write_auto_pre =>
                IF (command = nop) OR (cur_bank /= bank) THEN
                    IF (Burst_Cnt(bank) = Burst_Length OR WB = single) THEN
                        statebank(bank) <= precharge, idle AFTER tdevice_TRP;
                        Burst_Cnt(bank) := 0;
                        ras_in(bank) <= '1';
                    ELSE
                        IF (Burst = sequential) THEN
                            Burst_Inc(bank) := (Burst_Inc(bank) + 1) MOD
                                                Burst_Length;
                        ELSE
                            Burst_Inc(bank) := intab(StartAddr(bank))
                                                    (Burst_Cnt(bank));
                        END IF;
                        Location := BaseLoc(bank) + Burst_Inc(bank);
                        IF (DQM_nwv = '0') THEN
                            IF Violation = '0' THEN
                                MemData(Bank)(Location) :=
                                    to_nat(DataIn(7 downto 0));
                            ELSE
                                MemData(Bank)(Location) := -1;
                            END IF;
                        END IF;
                        Burst_Cnt(bank) := Burst_Cnt(bank) + 1;
                        wrt_in <= '1';
                    END IF;
                ELSE
                    ASSERT false
                        REPORT InstancePath & partID & BankString &
                               ": Illegal command"
                               & " received in write state."
                        SEVERITY SeverityMode;
                END IF;

            WHEN read_auto_pre =>
                IF (command = nop) OR (cur_bank /= bank) THEN
                    IF (Burst_Cnt(bank) = Burst_Length) THEN
                        statebank(bank) <= precharge, idle AFTER tdevice_TRP;
                        Burst_Cnt(bank) := 0;
                        ras_in(bank) <= '1';
                    ELSE
                        IF (Burst = sequential) THEN
                            Burst_Inc(bank) := (Burst_Inc(bank) + 1) MOD
                                                Burst_Length;
                        ELSE
                            Burst_Inc(bank) := intab(StartAddr(bank))
                                                    (Burst_Cnt(bank));
                        END IF;
                        Location := BaseLoc(bank) + Burst_Inc(bank);
                        IF MemData(Bank)(Location) = -2 THEN
                            DataDrive := (others => 'U');
                        ELSIF MemData(Bank)(Location) = -1 THEN
                            DataDrive := (others => 'X');
                        ELSE
                            DataDrive := to_slv(MemData(Bank)(Location),8);
                        END IF;
                        Burst_Cnt(bank) := Burst_Cnt(bank) + 1;
                    END IF;
                ELSIF (command = read) AND (cur_bank /= bank) THEN
                   statebank(bank) <= precharge, idle AFTER tdevice_TRP;
                ELSE
                    ASSERT false
                        REPORT InstancePath & partID & BankString &
                               ": Illegal command"
                               & " received in read state."
                        SEVERITY SeverityMode;
                END IF;

            WHEN others => null;
        END CASE;
        END LOOP banks;

    -- Check Refresh Status
        IF (written = true) THEN
            ASSERT Ref_Cnt > 0
                REPORT InstancePath & partID &
                       ": memory not refreshed (by ref_cnt)"
                SEVERITY SeverityMode;
        END IF;

    END IF;

    -- Latency adjustments and DQM read masking

    IF (rising_edge(CLKIn)) THEN
        IF (rising_edge(CLKIn) AND CKEreg = '1') THEN
            DataDrive3 := DataDrive2;
            DataDrive2 := DataDrive1;
            DataDrive1 := DataDrive;
        END IF;
        IF (DQM_reg1 = '0') THEN
            IF (CAS_Lat = 3) THEN
                DataDriveOut(7 downto 0) := DataDrive3;
            ELSE
                DataDriveOut(7 downto 0) := DataDrive2;
            END IF;
        ELSE
            DataDriveOut(7 downto 0) := (others => 'Z');
        END IF;
    END IF;

    -- The Powering-down State Machine
    IF (rising_edge(CLKIn) AND CKEreg = '1' AND CKEIn = '0') THEN

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

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

        CASE statebank(cur_bank) IS
            WHEN idle =>
                IF (command = nop) THEN
                    statebank <= pwrdwn & pwrdwn & pwrdwn & pwrdwn;
                ELSIF (command = ref) THEN
                    statebank <= self_refresh & self_refresh & self_refresh
                             & self_refresh;
                END IF;
            WHEN write =>
                    statebank(cur_bank) <= write_suspend;
            WHEN read =>
                    statebank(cur_bank) <= read_suspend;
            WHEN bank_act =>
                IF (command = writ) THEN
                    statebank(cur_bank) <= write_suspend;
                ELSIF (command = read) THEN
                    statebank(cur_bank) <= read_suspend;
                ELSE
                    statebank(cur_bank) <= bank_act_pwrdwn;
                END IF;
            WHEN others => null;
        END CASE;

    END IF;

    -- The Powering-up State Machine
    IF (rising_edge(CLKIn) AND CKEreg = '0' AND CKEIn = '1') THEN

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

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

        CASE statebank(cur_bank) IS
            WHEN write_suspend =>
                statebank(cur_bank) <= write;
            WHEN read_suspend =>
                statebank(cur_bank) <= read;
            WHEN self_refresh =>
                statebank <= idle & idle & idle & idle after tdevice_TRP;
                Ref_Cnt := 4096;
                ASSERT command = nop
                    REPORT InstancePath & partID & ": Illegal command received"
                           & " during self_refresh."
                    SEVERITY SeverityMode;
            WHEN pwrdwn =>
               statebank <= idle & idle & idle & idle;
            WHEN bank_act_pwrdwn =>
                statebank(cur_bank) <= bank_act;
            WHEN others => null;
        END CASE;

    END IF;

    --------------------------------------------------------------------
    -- File Read Section
    --------------------------------------------------------------------
    IF PoweredUp'EVENT and PoweredUp and (mem_file_name /= "none") THEN
        ind := 0;
        WHILE (not ENDFILE (mem_file)) LOOP
            READLINE (mem_file, buf);
            IF buf(1