IF Read_precharge (2) = '1' OR Write_precharge (2) = '1' THEN
                Count_precharge (2) := Count_precharge (2) + 1;
            END IF;
            IF Read_precharge (3) = '1' OR Write_precharge (3) = '1' THEN
                Count_precharge (3) := Count_precharge (3) + 1;
            END IF;

            -- Read with AutoPrecharge Calculation
            --      The device start internal precharge when:
            --          1.  Meet tRAS requirement
            --          2.  BL/2 cycles after command
            IF ((Read_precharge(0) = '1') AND (NOW - RAS_chk0 >= tRAS)) THEN
                IF ((Burst_length_2 = '1' AND Count_precharge(0) >= 1)  OR
                    (Burst_length_4 = '1' AND Count_precharge(0) >= 2)  OR
                    (Burst_length_8 = '1' AND Count_precharge(0) >= 4)) THEN
                    Pc_b0 := '1';
                    Act_b0 := '0';
                    RP_chk0 := NOW;
                    Read_precharge(0) := '0';
                END IF;
            END IF;
            IF ((Read_precharge(1) = '1') AND (NOW - RAS_chk1 >= tRAS)) THEN
                IF ((Burst_length_2 = '1' AND Count_precharge(1) >= 1)  OR
                    (Burst_length_4 = '1' AND Count_precharge(1) >= 2)  OR
                    (Burst_length_8 = '1' AND Count_precharge(1) >= 4)) THEN
                    Pc_b1 := '1';
                    Act_b1 := '0';
                    RP_chk1 := NOW;
                    Read_precharge(1) := '0';
                END IF;
            END IF;
            IF ((Read_precharge(2) = '1') AND (NOW - RAS_chk2 >= tRAS)) THEN
                IF ((Burst_length_2 = '1' AND Count_precharge(2) >= 1)  OR
                    (Burst_length_4 = '1' AND Count_precharge(2) >= 2)  OR
                    (Burst_length_8 = '1' AND Count_precharge(2) >= 4)) THEN
                    Pc_b2 := '1';
                    Act_b2 := '0';
                    RP_chk2 := NOW;
                    Read_precharge(2) := '0';
                END IF;
            END IF;
            IF ((Read_precharge(3) = '1') AND (NOW - RAS_chk3 >= tRAS)) THEN
                IF ((Burst_length_2 = '1' AND Count_precharge(3) >= 1)  OR
                    (Burst_length_4 = '1' AND Count_precharge(3) >= 2)  OR
                    (Burst_length_8 = '1' AND Count_precharge(3) >= 4)) THEN
                    Pc_b3 := '1';
                    Act_b3 := '0';
                    RP_chk3 := NOW;
                    Read_precharge(3) := '0';
                END IF;
            END IF;

            -- Write with AutoPrecharge Calculation
            --      The device start internal precharge when:
            --          1.  Meet tRAS requirement
            --          2.  Two clock after last burst
            -- Since tWR is time base, the model will compensate tRP
            IF ((Write_precharge(0) = '1') AND (NOW - RAS_chk0 >= tRAS)) THEN
                IF ((Burst_length_2 = '1' AND Count_precharge (0) >= 4) OR
                    (Burst_length_4 = '1' AND Count_precharge (0) >= 5) OR
                    (Burst_length_8 = '1' AND Count_precharge (0) >= 7)) THEN
                    Pc_b0 := '1';
                    Act_b0 := '0';
                    RP_chk0 := NOW - ((2 * tCK) - tWR);
                    Write_precharge(0) := '0';
                END IF;
            END IF;
            IF ((Write_precharge(1) = '1') AND (NOW - RAS_chk1 >= tRAS)) THEN
                IF ((Burst_length_2 = '1' AND Count_precharge (1) >= 4) OR
                    (Burst_length_4 = '1' AND Count_precharge (1) >= 5) OR
                    (Burst_length_8 = '1' AND Count_precharge (1) >= 7)) THEN
                    Pc_b1 := '1';
                    Act_b1 := '0';
                    RP_chk1 := NOW - ((2 * tCK) - tWR);
                    Write_precharge(1) := '0';
                END IF;
            END IF;
            IF ((Write_precharge(2) = '1') AND (NOW - RAS_chk2 >= tRAS)) THEN
                IF ((Burst_length_2 = '1' AND Count_precharge (2) >= 4) OR
                    (Burst_length_4 = '1' AND Count_precharge (2) >= 5) OR
                    (Burst_length_8 = '1' AND Count_precharge (2) >= 7)) THEN
                    Pc_b2 := '1';
                    Act_b2 := '0';
                    RP_chk2 := NOW - ((2 * tCK) - tWR);
                    Write_precharge(2) := '0';
                END IF;
            END IF;
            IF ((Write_precharge(3) = '1') AND (NOW - RAS_chk3 >= tRAS)) THEN
                IF ((Burst_length_2 = '1' AND Count_precharge (3) >= 4) OR
                    (Burst_length_4 = '1' AND Count_precharge (3) >= 5) OR
                    (Burst_length_8 = '1' AND Count_precharge (3) >= 7)) THEN
                    Pc_b3 := '1';
                    Act_b3 := '0';
                    RP_chk3 := NOW - ((2 * tCK) - tWR);
                    Write_precharge(3) := '0';
                END IF;
            END IF;
        END IF;
        
        --
        -- DLL Counter
        --
        IF Sys_clk'EVENT AND Sys_clk = '1' THEN
            IF (DLL_Reset = '1' AND DLL_done = '0') THEN
                DLL_count := DLL_count + 1;
                IF (DLL_count >= 200) THEN
                    DLL_done := '1';
                END IF;
            END IF;
        END IF;

        --
        -- Control Logic
        --
        IF Sys_clk'EVENT AND Sys_clk = '1' THEN
            -- Auto Refresh
            IF Aref_enable = '1' THEN
                -- Auto Refresh to Auto Refresh
                ASSERT (NOW - RFC_chk >= tRFC)
                    REPORT "tRFC violation during Auto Refresh"
                    SEVERITY WARNING;

                -- Precharge to Auto Refresh
                ASSERT ((NOW - RP_chk0 >= tRP) AND (NOW - RP_chk1 >= tRP) AND
                        (NOW - RP_chk2 >= tRP) AND (NOW - RP_chk3 >= tRP))
                    REPORT "tRP violation during Auto Refresh"
                    SEVERITY WARNING;

                -- Precharge to Auto Refresh
                ASSERT (Pc_b0 = '1' AND Pc_b1 = '1' AND Pc_b2 = '1' AND Pc_b3 = '1')
                    REPORT "All banks must be Precharge before Auto Refresh"
                    SEVERITY WARNING;

                -- Record current tRFC time
                RFC_chk := NOW;
            END IF;

            -- Extended Load Mode Register
            IF Ext_mode_enable = '1' THEN
                IF (Pc_b0 = '1' AND Pc_b1 = '1' AND Pc_b2 = '1' AND Pc_b3 = '1') THEN
                    IF (Addr (0) = '0') THEN
                        DLL_enable := '1';
                    ELSE
                        DLL_enable := '0';
                    END IF;
                END IF;
                
                -- Precharge to EMR
                ASSERT (Pc_b0 = '1' AND Pc_b1 = '1' AND Pc_b2 = '1' AND Pc_b3 = '1')
                    REPORT "All bank must be Precharged before Extended Mode Register"
                    SEVERITY WARNING;
                
                -- Precharge to EMR
                ASSERT ((NOW - RP_chk0 >= tRP) AND (NOW - RP_chk1 >= tRP) AND
                        (NOW - RP_chk2 >= tRP) AND (NOW - RP_chk3 >= tRP))
                    REPORT "tRP violation during Extended Load Register"
                    SEVERITY WARNING;

                -- LMR/EMR to EMR
                ASSERT (NOW - MRD_chk >= tMRD)
                    REPORT "tMRD violation during Extended Mode Register"
                    SEVERITY WARNING;

                -- Record current tMRD time
                MRD_chk := NOW;
            END IF;

            -- Load Mode Register
            IF Mode_reg_enable = '1' THEN
                -- Register mode
                Mode_reg <= Addr;
                
                -- DLL Reset
                IF (DLL_enable = '1' AND Addr (8) = '1') THEN
                    DLL_reset := '1';
                    DLL_done  := '0';
                    DLL_count := 0;
                ELSIF (DLL_enable = '1' AND DLL_reset = '0' AND Addr (8) = '0') THEN
                    ASSERT (FALSE)
                        REPORT "DLL is ENABLE: DLL RESET is require"
                        SEVERITY WARNING;
                ELSIF (DLL_enable = '0' AND Addr (8) = '1') THEN
                    ASSERT (FALSE)
                        REPORT "DLL is DISABLE: DLL RESET will be ignored"
                        SEVERITY WARNING;
                END IF;

                -- Precharge to LMR
                ASSERT (Pc_b0 = '1' AND Pc_b1 = '1' AND Pc_b2 = '1' AND Pc_b3 = '1')
                    REPORT "All bank must be Precharged before Load Mode Register"
                    SEVERITY WARNING;

                -- Precharge to EMR
                ASSERT ((NOW - RP_chk0 >= tRP) AND (NOW - RP_chk1 >= tRP) AND
                        (NOW - RP_chk2 >= tRP) AND (NOW - RP_chk3 >= tRP))
                    REPORT "tRP violation during Load Mode Register"
                    SEVERITY WARNING;

                -- LMR/ELMR to LMR
                ASSERT (NOW - MRD_chk >= tMRD)
                    REPORT "tMRD violation during Load Mode Register"
                    SEVERITY WARNING;

                -- Check for invalid Burst Length
                ASSERT ((Addr (2 DOWNTO 0) = "001") OR      -- BL = 2
                        (Addr (2 DOWNTO 0) = "010") OR      -- BL = 4
                        (Addr (2 DOWNTO 0) = "011"))        -- BL = 8
                    REPORT "Invalid Burst Length during Load Mode Register"
                    SEVERITY WARNING;

                -- Check for invalid CAS Latency
                ASSERT ((Addr (6 DOWNTO 4) = "010") OR      -- CL = 2.0
                        (Addr (6 DOWNTO 4) = "110"))        -- CL = 2.5
                    REPORT "Invalid CAS Latency during Load Mode Register"
                    SEVERITY WARNING;

                -- Record current tMRD time
                MRD_chk := NOW;
            END IF;

            -- Active Block (latch Bank and Row Address)
            IF Active_enable = '1' THEN
                -- Activate an OPEN bank can corrupt data
                ASSERT ((Ba = "00" AND Act_b0 = '0') OR
                        (Ba = "01" AND Act_b1 = '0') OR
                        (Ba = "10" AND Act_b2 = '0') OR
                        (Ba = "11" AND Act_b3 = '0'))
                    REPORT "Bank is already activated - data can be corrupted"
                    SEVERITY WARNING;

                -- Activate Bank 0
                IF Ba = "00" AND Pc_b0 = '1' THEN
                    -- Activate to Activate (same bank)
                    ASSERT (NOW - RC_chk0 >= tRC)
                        REPORT "tRC violation during Activate Bank 0"
                        SEVERITY WARNING;

                    -- Precharge to Active
                    ASSERT (NOW - RP_chk0 >= tRP)
                        REPORT "tRP violation during Activate Bank 0"
                        SEVERITY WARNING;

                    -- Record Variables for checking violation
                    Act_b0 := '1';
                    Pc_b0 := '0';
                    B0_row_addr := Addr;
                    RC_chk0 := NOW;
                    RCD_chk0 := NOW;
                    RAS_chk0 := NOW;
                    RAP_chk0 := NOW;
                END IF;

                -- Activate Bank 1
                IF Ba = "01" AND Pc_b1 = '1' THEN
                    -- Activate to Activate (same bank)
                    ASSERT (NOW - RC_chk1 >= tRC)
                        REPORT "tRC violation during Activate Bank 1"
                        SEVERITY WARNING;

                    -- Precharge to Active
                    ASSERT (NOW - RP_chk1 >= tRP)
                        REPORT "tRP violation during Activate Bank 1"
                        SEVERITY WARNING;

                    -- Record Variables for checking violation
                    Act_b1 := '1';
                    Pc_b1 := '0';
                    B1_row_addr := Addr;
                    RC_chk1 := NOW;
                    RCD_chk1 := NOW;
                    RAS_chk1 := NOW;
                    RAP_chk1 := NOW;
                END IF;

                -- Activate Bank 2
                IF Ba = "10" AND Pc_b2 = '1' THEN
                    -- Activate to Activate (same bank)
                    ASSERT (NOW - RC_chk2 >= tRC)
                        REPORT "tRC violation during Activate Bank 2"
                        SEVERITY WARNING;

                    -- Precharge to Active
                    ASSERT (NOW - RP_chk2 >= tRP)
                        REPORT "tRP violation during Activate Bank 2"
                        SEVERITY WARNING;

                    -- Record Variables for checking violation
                    Act_b2 := '1';
                    Pc_b2 := '0';
                    B2_row_addr := Addr;
                    RC_chk2 := NOW;
                    RCD_chk2 := NOW;
                    RAS_chk2 := NOW;
                    RAP_chk2 := NOW;
                END IF;

                -- Activate Bank 3
                IF Ba = "11" AND Pc_b3 = '1' THEN
                    -- Activate to Activate (same bank)
                    ASSERT (NOW - RC_chk3 >= tRC)
                        REPORT "tRC violation during Activate Bank 3"
                        SEVERITY WARNING;

                    -- Precharge to Active
                    ASSERT (NOW - RP_chk3 >= tRP)
                        REPORT "tRP violation during Activate Bank 3"
                        SEVERITY WARNING;

                    -- Record Variables for checking violation
                    Act_b3 := '1';
                    Pc_b3 := '0';
                    B3_row_addr := Addr;
                    RC_chk3 := NOW;
                    RCD_chk3 := NOW;
                    RAS_chk3 := NOW;
                    RAP_chk3 := NOW;
                END IF;

                -- Activate Bank A to Activate Bank B
                IF (Prev_bank /= Ba) THEN
                    ASSERT (NOW - RRD_chk >= tRRD)
                        REPORT "tRRD violation during Activate"
                        SEVERITY WARNING;
                END IF;
                
                -- AutoRefresh to Activate
                ASSERT (NOW - RFC_chk >= tRFC)
                    REPORT "tRFC violation during Activate"
                    SEVERITY WARNING;
                
                -- Record Variables for Checking Violation