/**************************************************************************************** * * File Name: MT48LC8M8A2.V * Version: 0.0f * Date: July 8th, 1999 * Model: BUS Functional * Simulator: Model Technology (PC version 5.2e PE) * * Dependencies: None * * Author: Son P. Huynh * Email: sphuynh@micron.com * Phone: (208) 368-3825 * Company: Micron Technology, Inc. * Model: MT48LC8M16A2 (2Meg x 8 x 4 Banks) * * Description: Micron 128Mb SDRAM Verilog model * * Limitation: - Doesn't check for 4096 cycle refresh * * Note: - Set simulator resolution to "ps" accuracy * - Set Debug = 0 to disable $display messages * * Disclaimer: THESE DESIGNS ARE PROVIDED "AS IS" WITH NO WARRANTY * WHATSOEVER AND MICRON SPECIFICALLY DISCLAIMS ANY * IMPLIED WARRANTIES OF MERCHANTABILITY, FITNESS FOR * A PARTICULAR PURPOSE, OR AGAINST INFRINGEMENT. * * Copyright © 1998 Micron Semiconductor Products, Inc. * All rights researved * * Rev Author Phone Date Changes * ---- ---------------------------- ---------- --------------------------------------- * 0.0f Son Huynh 208-368-3825 07/08/1999 - Fix tWR = 1 Clk + 7.5 ns (Auto) * Micron Technology Inc. - Fix tWR = 15 ns (Manual) * - Fix tRP (Autoprecharge to AutoRefresh) * * 0.0a Son Huynh 208-368-3825 05/13/1998 - First Release (from 64Mb rev 0.0e) * Micron Technology Inc. ****************************************************************************************/ `timescale 1ns / 100ps module mt48lc8m8a2 (Dq, Addr, Ba, Clk, Cke, Cs_n, Ras_n, Cas_n, We_n, Dqm); parameter addr_bits = 12; parameter data_bits = 8; parameter col_bits = 9; parameter mem_sizes = 2097151; // 2 Meg inout [data_bits - 1 : 0] Dq; input [addr_bits - 1 : 0] Addr; input [1 : 0] Ba; input Clk; input Cke; input Cs_n; input Ras_n; input Cas_n; input We_n; input [0 : 0] Dqm; reg [data_bits - 1 : 0] Bank0 [0 : mem_sizes]; reg [data_bits - 1 : 0] Bank1 [0 : mem_sizes]; reg [data_bits - 1 : 0] Bank2 [0 : mem_sizes]; reg [data_bits - 1 : 0] Bank3 [0 : mem_sizes]; reg [1 : 0] Bank_addr [0 : 3]; // Bank Address Pipeline reg [col_bits - 1 : 0] Col_addr [0 : 3]; // Column Address Pipeline reg [3 : 0] Command [0 : 3]; // Command Operation Pipeline reg [0 : 0] Dqm_reg0, Dqm_reg1; // DQM Operation Pipeline reg [addr_bits - 1 : 0] B0_row_addr, B1_row_addr, B2_row_addr, B3_row_addr; reg [addr_bits - 1 : 0] Mode_reg; reg [data_bits - 1 : 0] Dq_reg, Dq_dqm; reg [col_bits - 1 : 0] Col_temp, Burst_counter; reg Act_b0, Act_b1, Act_b2, Act_b3; // Bank Activate reg Pc_b0, Pc_b1, Pc_b2, Pc_b3; // Bank Precharge reg [1 : 0] Bank_precharge [0 : 3]; // Precharge Command reg A10_precharge [0 : 3]; // Addr[10] = 1 (All banks) reg Auto_precharge [0 : 3]; // RW AutoPrecharge (Bank) reg Read_precharge [0 : 3]; // R AutoPrecharge reg Write_precharge [0 : 3]; // W AutoPrecharge integer Count_precharge [0 : 3]; // RW AutoPrecharge (Counter) reg RW_interrupt_read [0 : 3]; // RW Interrupt Read with Auto Precharge reg RW_interrupt_write [0 : 3]; // RW Interrupt Write with Auto Precharge reg Data_in_enable; reg Data_out_enable; reg [1 : 0] Bank, Previous_bank; reg [addr_bits - 1 : 0] Row; reg [col_bits - 1 : 0] Col, Col_brst; // Internal system clock reg CkeZ, Sys_clk; // Commands Decode wire Active_enable = ~Cs_n & ~Ras_n & Cas_n & We_n; wire Aref_enable = ~Cs_n & ~Ras_n & ~Cas_n & We_n; wire Burst_term = ~Cs_n & Ras_n & Cas_n & ~We_n; wire Mode_reg_enable = ~Cs_n & ~Ras_n & ~Cas_n & ~We_n; wire Prech_enable = ~Cs_n & ~Ras_n & Cas_n & ~We_n; wire Read_enable = ~Cs_n & Ras_n & ~Cas_n & We_n; wire Write_enable = ~Cs_n & Ras_n & ~Cas_n & ~We_n; // Burst Length Decode wire Burst_length_1 = ~Mode_reg[2] & ~Mode_reg[1] & ~Mode_reg[0]; wire Burst_length_2 = ~Mode_reg[2] & ~Mode_reg[1] & Mode_reg[0]; wire Burst_length_4 = ~Mode_reg[2] & Mode_reg[1] & ~Mode_reg[0]; wire Burst_length_8 = ~Mode_reg[2] & Mode_reg[1] & Mode_reg[0]; // CAS Latency Decode wire Cas_latency_2 = ~Mode_reg[6] & Mode_reg[5] & ~Mode_reg[4]; wire Cas_latency_3 = ~Mode_reg[6] & Mode_reg[5] & Mode_reg[4]; `ifdef VERBOSE wire Debug = 1'b1; // Debug messages : 1 = On `else wire Debug = 1'b0; // Debug messages : 1 = On `endif // Write Burst Mode wire Write_burst_mode = Mode_reg[9]; wire Dq_chk = Sys_clk & Data_in_enable; // Check setup/hold time for DQ assign Dq = Dq_reg; // DQ buffer // Commands Operation `define ACT 0 `define NOP 1 `define READ 2 `define READ_A 3 `define SDRAM_WRITE 4 `define WRITE_A 5 `define SDRAM_PRECH 6 `define SDRAM_A_REF 7 `define SDRAM_BST 8 `define SDRAM_LMR 9 // Timing Parameters for -75 (PC133) and CAS Latency = 2 parameter tAC = 6.0; parameter tHZ = 7.0; parameter tOH = 2.7; parameter tMRD = 2.0; // 2 Clk Cycles parameter tRAS = 44.0; parameter tRC = 66.0; parameter tRCD = 20.0; parameter tRP = 20.0; parameter tRRD = 15.0; parameter tWRa = 7.5; // A2 Version - Auto precharge mode only (1 Clk + 7.5 ns) parameter tWRp = 15.0; // A2 Version - Precharge mode only (15 ns) // Timing Check variable integer MRD_chk; integer WR_counter [0 : 3]; time WR_chk [0 : 3]; time RC_chk, RRD_chk; time RAS_chk0, RAS_chk1, RAS_chk2, RAS_chk3; time RCD_chk0, RCD_chk1, RCD_chk2, RCD_chk3; time RP_chk0, RP_chk1, RP_chk2, RP_chk3; initial begin Dq_reg = {data_bits{1'bz}}; {Data_in_enable, Data_out_enable} = 0; {Act_b0, Act_b1, Act_b2, Act_b3} = 4'b0000; {Pc_b0, Pc_b1, Pc_b2, Pc_b3} = 4'b0000; {WR_chk[0], WR_chk[1], WR_chk[2], WR_chk[3]} = 0; {WR_counter[0], WR_counter[1], WR_counter[2], WR_counter[3]} = 0; {RW_interrupt_read[0], RW_interrupt_read[1], RW_interrupt_read[2], RW_interrupt_read[3]} = 0; {RW_interrupt_write[0], RW_interrupt_write[1], RW_interrupt_write[2], RW_interrupt_write[3]} = 0; {MRD_chk, RC_chk, RRD_chk} = 0; {RAS_chk0, RAS_chk1, RAS_chk2, RAS_chk3} = 0; {RCD_chk0, RCD_chk1, RCD_chk2, RCD_chk3} = 0; {RP_chk0, RP_chk1, RP_chk2, RP_chk3} = 0; $timeformat (-9, 0, " ns", 12); //$readmemh("bank0.txt", Bank0); //$readmemh("bank1.txt", Bank1); //$readmemh("bank2.txt", Bank2); //$readmemh("bank3.txt", Bank3); end // System clock generator always begin @ (posedge Clk) begin Sys_clk = CkeZ; CkeZ = Cke; end @ (negedge Clk) begin Sys_clk = 1'b0; end end always @ (posedge Sys_clk) begin // Internal Commamd Pipelined Command[0] = Command[1]; Command[1] = Command[2]; Command[2] = Command[3]; Command[3] = `NOP; Col_addr[0] = Col_addr[1]; Col_addr[1] = Col_addr[2]; Col_addr[2] = Col_addr[3]; Col_addr[3] = {col_bits{1'b0}}; Bank_addr[0] = Bank_addr[1]; Bank_addr[1] = Bank_addr[2]; Bank_addr[2] = Bank_addr[3]; Bank_addr[3] = 2'b0; Bank_precharge[0] = Bank_precharge[1]; Bank_precharge[1] = Bank_precharge[2]; Bank_precharge[2] = Bank_precharge[3]; Bank_precharge[3] = 2'b0; A10_precharge[0] = A10_precharge[1]; A10_precharge[1] = A10_precharge[2]; A10_precharge[2] = A10_precharge[3]; A10_precharge[3] = 1'b0; // Dqm pipeline for Read Dqm_reg0 = Dqm_reg1; Dqm_reg1 = Dqm; // Read or Write with Auto Precharge Counter if (Auto_precharge[0] == 1'b1) begin Count_precharge[0] = Count_precharge[0] + 1; end if (Auto_precharge[1] == 1'b1) begin Count_precharge[1] = Count_precharge[1] + 1; end if (Auto_precharge[2] == 1'b1) begin Count_precharge[2] = Count_precharge[2] + 1; end if (Auto_precharge[3] == 1'b1) begin Count_precharge[3] = Count_precharge[3] + 1; end // tMRD Counter MRD_chk = MRD_chk + 1; // tWR Counter for Write WR_counter[0] = WR_counter[0] + 1; WR_counter[1] = WR_counter[1] + 1; WR_counter[2] = WR_counter[2] + 1; WR_counter[3] = WR_counter[3] + 1; // Auto Refresh if (Aref_enable == 1'b1) begin if (Debug) $display ("at time %t AREF : Auto Refresh", $time); // Auto Refresh to Auto Refresh if ($time - RC_chk < tRC) begin //->tb.test_control.error_detected; $display ("at time %t ERROR: tRC violation during Auto Refresh", $time); end // Precharge to Auto Refresh if ($time - RP_chk0 < tRP || $time - RP_chk1 < tRP || $time - RP_chk2 < tRP || $time - RP_chk3 < tRP) begin //->tb.test_control.error_detected; $display ("at time %t ERROR: tRP violation during Auto Refresh", $time); end // Precharge to Refresh if (Pc_b0 == 1'b0 || Pc_b1 == 1'b0 || Pc_b2 == 1'b0 || Pc_b3 == 1'b0) begin //->tb.test_control.error_detected; $display ("at time %t ERROR: All banks must be Precharge before Auto Refresh", $time); end // Record Current tRC time RC_chk = $time; end // Load Mode Register if (Mode_reg_enable == 1'b1) begin // Decode CAS Latency, Burst Length, Burst Type, and Write Burst Mode if (Pc_b0 == 1'b1 && Pc_b1 == 1'b1 && Pc_b2 == 1'b1 && Pc_b3 == 1'b1) begin Mode_reg = Addr; if (Debug) begin $display ("at time %t LMR : Load Mode Register", $time); // CAS Latency if (Addr[6 : 4] == 3'b010) $display (" CAS Latency = 2"); else if (Addr[6 : 4] == 3'b011) $display (" CAS Latency = 3"); else $display (" CAS Latency = Reserved"); // Burst Length if (Addr[2 : 0] == 3'b000) $display (" Burst Length = 1"); else if (Addr[2 : 0] == 3'b001) $display (" Burst Length = 2"); else if (Addr[2 : 0] == 3'b010) $display (" Burst Length = 4"); else if (Addr[2 : 0] == 3'b011) $display (" Burst Length = 8"); else if (Addr[3 : 0] == 4'b0111) $display (" Burst Length = Full"); else $display (" Burst Length = Reserved"); // Burst Type if (Addr[3] == 1'b0) $display (" Burst Type = Sequential"); else if (Addr[3] == 1'b1) $display (" Burst Type = Interleaved"); else $display (" Burst Type = Reserved"); // Write Burst Mode if (Addr[9] == 1'b0) $display (" Write Burst Mode = Programmed Burst Length"); else if (Addr[9] == 1'b1) $display (" Write Burst Mode = Single Location Access"); else $display (" Write Burst Mode = Reserved"); end end else begin //->tb.test_control.error_detected; $display ("at time %t ERROR: all banks must be Precharge before Load Mode Register", $time); end // REF to LMR if ($time - RC_chk < tRC) begin //->tb.test_control.error_detected; $display ("at time %t ERROR: tRC violation during Load Mode Register", $time); end // LMR to LMR if (MRD_chk < tMRD) begin //->tb.test_control.error_detected; $display ("at time %t ERROR: tMRD violation during Load Mode Register", $time); end MRD_chk = 0; end // Active Block (Latch Bank Address and Row Address) if (Active_enable == 1'b1) begin if (Ba == 2'b00 && Pc_b0 == 1'b1) begin {Act_b0, Pc_b0} = 2'b10; B0_row_addr = Addr [addr_bits - 1 : 0]; RCD_chk0 = $time; RAS_chk0 = $time; if (Debug) $display ("at time %t ACT : Bank = 0 Row = %d", $time, Addr); // Precharge to Activate Bank 0 if ($time - RP_chk0 < tRP) begin //->tb.test_control.error_detected; $display ("at time %t ERROR: tRP violation during Activate bank 0", $time); end end else if (Ba == 2'b01 && Pc_b1 == 1'b1) begin {Act_b1, Pc_b1} = 2'b10; B1_row_addr = Addr [addr_bits - 1 : 0]; RCD_chk1 = $time; RAS_chk1 = $time; if (Debug) $display ("at time %t ACT : Bank = 1 Row = %d", $time, Addr); // Precharge to Activate Bank 1 if ($time - RP_chk1 < tRP) begin //->tb.test_control.error_detected; $display ("at time %t ERROR: tRP violation during Activate bank 1", $time); end end else if (Ba == 2'b10 && Pc_b2 == 1'b1) begin {Act_b2, Pc_b2} = 2'b10; B2_row_addr = Addr [addr_bits - 1 : 0]; RCD_chk2 = $time; RAS_chk2 = $time; if (Debug) $display ("at time %t ACT : Bank = 2 Row = %d", $time, Addr); // Precharge to Activate Bank 2 if ($time - RP_chk2 < tRP) begin //->tb.test_control.error_detected; $display ("at time %t ERROR: tRP violation during Activate bank 2", $time); end end else if (Ba == 2'b11 && Pc_b3 == 1'b1) begin {Act_b3, Pc_b3} = 2'b10; B3_row_addr = Addr [addr_bits - 1 : 0]; RCD_chk3 = $time; RAS_chk3 = $time; if (Debug) $display ("at time %t ACT : Bank = 3 Row = %d", $time, Addr); // Precharge to Activate Bank 3 if ($time - RP_chk3 < tRP) begin //->tb.test_control.error_detected; $display ("at time %t ERROR: tRP violation during Activate bank 3", $time); end end else if (Ba == 2'b00 && Pc_b0 == 1'b0) begin //->tb.test_control.error_detected; $display ("at time %t ERROR: Bank 0 is not Precharged.", $time); end else if (Ba == 2'b01 && Pc_b1 == 1'b0) begin //->tb.test_control.error_detected; $display ("at time %t ERROR: Bank 1 is not Precharged.", $time); end else if (Ba == 2'b10 && Pc_b2 == 1'b0) begin //->tb.test_control.error_detected; $display ("at time %t ERROR: Bank 2 is not Precharged.", $time); end else if (Ba == 2'b11 && Pc_b3 == 1'b0) begin //->tb.test_control.error_detected; $display ("at time %t ERROR: Bank 3 is not Precharged.", $time); end // Active Bank A to Active Bank B if ((Previous_bank != Ba) && ($time - RRD_chk < tRRD)) begin //->tb.test_control.error_detected; $display ("at time %t ERROR: tRRD violation during Activate bank = %d", $time, Ba); end // Load Mode Register to Active if (MRD_chk < tMRD ) begin //->tb.test_control.error_detected; $display ("at time %t ERROR: tMRD violation during Activate bank = %d", $time, Ba); end // Auto Refresh to Activate if ($time - RC_chk < tRC) begin //->tb.test_control.error_detected; $display ("at time %t ERROR: tRC violation during Activate bank = %d", $time, Ba); end // Record variables for checking violation RRD_chk = $time; Previous_bank = Ba; end // Precharge Block if (Prech_enable == 1'b1) begin if (Addr[10] == 1'b1) begin {Pc_b0, Pc_b1, Pc_b2, Pc_b3} = 4'b1111; {Act_b0, Act_b1, Act_b2, Act_b3} = 4'b0000; RP_chk0 = $time; RP_chk1 = $time; RP_chk2 = $time; RP_chk3 = $time; if (Debug) $display ("at time %t PRE : Bank = ALL",$time); // Activate to Precharge all banks if (($time - RAS_chk0 < tRAS) || ($time - RAS_chk1 < tRAS) || ($time - RAS_chk2 < tRAS) || ($time - RAS_chk3 < tRAS)) begin //->tb.test_control.error_detected; $display ("at time %t ERROR: tRAS violation during Precharge all bank", $time); end // tWR violation check for write if (($time - WR_chk[0] < tWRp) || ($time - WR_chk[1] < tWRp) || ($time - WR_chk[2] < tWRp) || ($time - WR_chk[3] < tWRp)) begin //->tb.test_control.error_detected; $display ("at time %t ERROR: tWR violation during Precharge all bank", $time); end end else if (Addr[10] == 1'b0) begin if (Ba == 2'b00) begin {Pc_b0, Act_b0} = 2'b10; RP_chk0 = $time; if (Debug) $display ("at time %t PRE : Bank = 0",$time); // Activate to Precharge Bank 0 if ($time - RAS_chk0 < tRAS) begin //->tb.test_control.error_detected; $display ("at time %t ERROR: tRAS violation during Precharge bank 0", $time); end end else if (Ba == 2'b01) begin {Pc_b1, Act_b1} = 2'b10; RP_chk1 = $time; if (Debug) $display ("at time %t PRE : Bank = 1",$time); // Activate to Precharge Bank 1 if ($time - RAS_chk1 < tRAS) begin //->tb.test_control.error_detected; $display ("at time %t ERROR: tRAS violation during Precharge bank 1", $time); end end else if (Ba == 2'b10) begin {Pc_b2, Act_b2} = 2'b10; RP_chk2 = $time; if (Debug) $display ("at time %t PRE : Bank = 2",$time); // Activate to Precharge Bank 2 if ($time - RAS_chk2 < tRAS) begin //->tb.test_control.error_detected; $display ("at time %t ERROR: tRAS violation during Precharge bank 2", $time); end end else if (Ba == 2'b11) begin {Pc_b3, Act_b3} = 2'b10; RP_chk3 = $time; if (Debug) $display ("at time %t PRE : Bank = 3",$time); // Activate to Precharge Bank 3 if ($time - RAS_chk3 < tRAS) begin //->tb.test_control.error_detected; $display ("at time %t ERROR: tRAS violation during Precharge bank 3", $time); end end // tWR violation check for write if ($time - WR_chk[Ba] < tWRp) begin //->tb.test_control.error_detected; $display ("at time %t ERROR: tWR violation during Precharge bank %d", $time, Ba); end end // Terminate a Write Immediately (if same bank or all banks) if (Data_in_enable == 1'b1 && (Bank == Ba || Addr[10] == 1'b1)) begin Data_in_enable = 1'b0; end // Precharge Command Pipeline for Read if (Cas_latency_3 == 1'b1) begin Command[2] = `SDRAM_PRECH; Bank_precharge[2] = Ba; A10_precharge[2] = Addr[10]; end else if (Cas_latency_2 == 1'b1) begin Command[1] = `SDRAM_PRECH; Bank_precharge[1] = Ba; A10_precharge[1] = Addr[10]; end end // Burst terminate if (Burst_term == 1'b1) begin // Terminate a Write Immediately if (Data_in_enable == 1'b1) begin Data_in_enable = 1'b0; end // Terminate a Read Depend on CAS Latency if (Cas_latency_3 == 1'b1) begin Command[2] = `SDRAM_BST; end else if (Cas_latency_2 == 1'b1) begin Command[1] = `SDRAM_BST; end if (Debug) $display ("at time %t BST : Burst Terminate",$time); end // Read, Write, Column Latch if (Read_enable == 1'b1 || Write_enable == 1'b1) begin // Check to see if bank is open (ACT) if ((Ba == 2'b00 && Pc_b0 == 1'b1) || (Ba == 2'b01 && Pc_b1 == 1'b1) || (Ba == 2'b10 && Pc_b2 == 1'b1) || (Ba == 2'b11 && Pc_b3 == 1'b1)) begin //->tb.test_control.error_detected; $display("at time %t ERROR: Cannot Read or Write - Bank %d is not Activated", $time, Ba); end // Activate to Read or Write if ((Ba == 2'b00) && ($time - RCD_chk0 < tRCD)) begin //->tb.test_control.error_detected; $display("at time %t ERROR: tRCD violation during Read or Write to Bank 0", $time); end if ((Ba == 2'b01) && ($time - RCD_chk1 < tRCD)) begin //->tb.test_control.error_detected; $display("at time %t ERROR: tRCD violation during Read or Write to Bank 1", $time); end if ((Ba == 2'b10) && ($time - RCD_chk2 < tRCD)) begin //->tb.test_control.error_detected; $display("at time %t ERROR: tRCD violation during Read or Write to Bank 2", $time); end if ((Ba == 2'b11) && ($time - RCD_chk3 < tRCD)) begin //->tb.test_control.error_detected; $display("at time %t ERROR: tRCD violation during Read or Write to Bank 3", $time); end // Read Command if (Read_enable == 1'b1) begin // CAS Latency pipeline if (Cas_latency_3 == 1'b1) begin if (Addr[10] == 1'b1) begin Command[2] = `READ_A; end else begin Command[2] = `READ; end Col_addr[2] = Addr; Bank_addr[2] = Ba; end else if (Cas_latency_2 == 1'b1) begin if (Addr[10] == 1'b1) begin Command[1] = `READ_A; end else begin Command[1] = `READ; end Col_addr[1] = Addr; Bank_addr[1] = Ba; end // Read interrupt Write (terminate Write immediately) if (Data_in_enable == 1'b1) begin Data_in_enable = 1'b0; end // Write Command end else if (Write_enable == 1'b1) begin if (Addr[10] == 1'b1) begin Command[0] = `WRITE_A; end else begin Command[0] = `SDRAM_WRITE; end Col_addr[0] = Addr; Bank_addr[0] = Ba; // Write interrupt Write (terminate Write immediately) if (Data_in_enable == 1'b1) begin Data_in_enable = 1'b0; end // Write interrupt Read (terminate Read immediately) if (Data_out_enable == 1'b1) begin Data_out_enable = 1'b0; end end // Interrupting a Write with Autoprecharge if (Auto_precharge[Bank] == 1'b1 && Write_precharge[Bank] == 1'b1) begin RW_interrupt_write[Bank] = 1'b1; if (Debug) $display ("at time %t NOTE : Read/Write Bank %d interrupt Write Bank %d with Autoprecharge", $time, Ba, Bank); end // Interrupting a Read with Autoprecharge if (Auto_precharge[Bank] == 1'b1 && Read_precharge[Bank] == 1'b1) begin RW_interrupt_read[Bank] = 1'b1; if (Debug) $display ("at time %t NOTE : Read/Write Bank %d interrupt Read Bank %d with Autoprecharge", $time, Ba, Bank); end // Read or Write with Auto Precharge if (Addr[10] == 1'b1) begin Auto_precharge[Ba] = 1'b1; Count_precharge[Ba] = 0; if (Read_enable == 1'b1) begin Read_precharge[Ba] = 1'b1; end else if (Write_enable == 1'b1) begin Write_precharge[Ba] = 1'b1; end end end // Read with Auto Precharge Calculation // The device start internal precharge: // 1. CAS Latency - 1 cycles before last burst // and 2. Meet minimum tRAS requirement // or 3. Interrupt by a Read or Write (with or without AutoPrecharge) if ((Auto_precharge[0] == 1'b1) && (Read_precharge[0] == 1'b1)) begin if ((($time - RAS_chk0 >= tRAS) && // Case 2 ((Burst_length_1 == 1'b1 && Count_precharge[0] >= 1) || // Case 1 (Burst_length_2 == 1'b1 && Count_precharge[0] >= 2) || (Burst_length_4 == 1'b1 && Count_precharge[0] >= 4) || (Burst_length_8 == 1'b1 && Count_precharge[0] >= 8))) || (RW_interrupt_read[0] == 1'b1)) begin // Case 3 Pc_b0 = 1'b1; Act_b0 = 1'b0; RP_chk0 = $time; Auto_precharge[0] = 1'b0; Read_precharge[0] = 1'b0; RW_interrupt_read[0] = 1'b0; if (Debug) $display ("at time %t NOTE : Start Internal Auto Precharge for Bank 0", $time); end end if ((Auto_precharge[1] == 1'b1) && (Read_precharge[1] == 1'b1)) begin if ((($time - RAS_chk1 >= tRAS) && ((Burst_length_1 == 1'b1 && Count_precharge[1] >= 1) || (Burst_length_2 == 1'b1 && Count_precharge[1] >= 2) || (Burst_length_4 == 1'b1 && Count_precharge[1] >= 4) || (Burst_length_8 == 1'b1 && Count_precharge[1] >= 8))) || (RW_interrupt_read[1] == 1'b1)) begin Pc_b1 = 1'b1; Act_b1 = 1'b0; RP_chk1 = $time; Auto_precharge[1] = 1'b0; Read_precharge[1] = 1'b0; RW_interrupt_read[1] = 1'b0; if (Debug) $display ("at time %t NOTE : Start Internal Auto Precharge for Bank 1", $time); end end if ((Auto_precharge[2] == 1'b1) && (Read_precharge[2] == 1'b1)) begin if ((($time - RAS_chk2 >= tRAS) && ((Burst_length_1 == 1'b1 && Count_precharge[2] >= 1) || (Burst_length_2 == 1'b1 && Count_precharge[2] >= 2) || (Burst_length_4 == 1'b1 && Count_precharge[2] >= 4) || (Burst_length_8 == 1'b1 && Count_precharge[2] >= 8))) || (RW_interrupt_read[2] == 1'b1)) begin Pc_b2 = 1'b1; Act_b2 = 1'b0; RP_chk2 = $time; Auto_precharge[2] = 1'b0; Read_precharge[2] = 1'b0; RW_interrupt_read[2] = 1'b0; if (Debug) $display ("at time %t NOTE : Start Internal Auto Precharge for Bank 2", $time); end end if ((Auto_precharge[3] == 1'b1) && (Read_precharge[3] == 1'b1)) begin if ((($time - RAS_chk3 >= tRAS) && ((Burst_length_1 == 1'b1 && Count_precharge[3] >= 1) || (Burst_length_2 == 1'b1 && Count_precharge[3] >= 2) || (Burst_length_4 == 1'b1 && Count_precharge[3] >= 4) || (Burst_length_8 == 1'b1 && Count_precharge[3] >= 8))) || (RW_interrupt_read[3] == 1'b1)) begin Pc_b3 = 1'b1; Act_b3 = 1'b0; RP_chk3 = $time; Auto_precharge[3] = 1'b0; Read_precharge[3] = 1'b0; RW_interrupt_read[3] = 1'b0; if (Debug) $display ("at time %t NOTE : Start Internal Auto Precharge for Bank 3", $time); end end // Internal Precharge or Bst if (Command[0] == `SDRAM_PRECH) begin // Precharge terminate a read with same bank or all banks if (Bank_precharge[0] == Bank || A10_precharge[0] == 1'b1) begin if (Data_out_enable == 1'b1) begin Data_out_enable = 1'b0; end end end else if (Command[0] == `SDRAM_BST) begin // BST terminate a read to current bank if (Data_out_enable == 1'b1) begin Data_out_enable = 1'b0; end end if (Data_out_enable == 1'b0) begin Dq_reg <= #tOH {data_bits{1'bz}}; end // Detect Read or Write command if (Command[0] == `READ || Command[0] == `READ_A) begin Bank = Bank_addr[0]; Col = Col_addr[0]; Col_brst = Col_addr[0]; if (Bank_addr[0] == 2'b00) begin Row = B0_row_addr; end else if (Bank_addr[0] == 2'b01) begin Row = B1_row_addr; end else if (Bank_addr[0] == 2'b10) begin Row = B2_row_addr; end else if (Bank_addr[0] == 2'b11) begin Row = B3_row_addr; end Burst_counter = 0; Data_in_enable = 1'b0; Data_out_enable = 1'b1; end else if (Command[0] == `SDRAM_WRITE || Command[0] == `WRITE_A) begin Bank = Bank_addr[0]; Col = Col_addr[0]; Col_brst = Col_addr[0]; if (Bank_addr[0] == 2'b00) begin Row = B0_row_addr; end else if (Bank_addr[0] == 2'b01) begin Row = B1_row_addr; end else if (Bank_addr[0] == 2'b10) begin Row = B2_row_addr; end else if (Bank_addr[0] == 2'b11) begin Row = B3_row_addr; end Burst_counter = 0; Data_in_enable = 1'b1; Data_out_enable = 1'b0; end // DQ buffer (Driver/Receiver) if (Data_in_enable == 1'b1) begin // Writing Data to Memory // Array buffer if (Bank == 2'b00) Dq_dqm [15 : 0] = Bank0 [{Row, Col}]; if (Bank == 2'b01) Dq_dqm [15 : 0] = Bank1 [{Row, Col}]; if (Bank == 2'b10) Dq_dqm [15 : 0] = Bank2 [{Row, Col}]; if (Bank == 2'b11) Dq_dqm [15 : 0] = Bank3 [{Row, Col}]; // Dqm operation if (Dqm[0] == 1'b0) Dq_dqm [ 7 : 0] = Dq [ 7 : 0]; // Write to memory if (Bank == 2'b00) Bank0 [{Row, Col}] = Dq_dqm [15 : 0]; if (Bank == 2'b01) Bank1 [{Row, Col}] = Dq_dqm [15 : 0]; if (Bank == 2'b10) Bank2 [{Row, Col}] = Dq_dqm [15 : 0]; if (Bank == 2'b11) Bank3 [{Row, Col}] = Dq_dqm [15 : 0]; // Output result if (Dqm == 1'b1) begin if (Debug) $display("at time %t WRITE: Bank = %d Row = %d, Col = %d, Data = Hi-Z due to DQM", $time, Bank, Row, Col); end else begin if (Debug) $display("at time %t WRITE: Bank = %d Row = %d, Col = %d, Data = %h, Dqm = %b", $time, Bank, Row, Col, Dq_dqm, Dqm); // Record tWR time and reset counter WR_chk [Bank] = $time; WR_counter [Bank] = 0; end // Advance burst counter subroutine #tHZ Burst; end else if (Data_out_enable == 1'b1) begin // Reading Data from Memory // Array buffer if (Bank == 2'b00) Dq_dqm [15 : 0] = Bank0 [{Row, Col}]; if (Bank == 2'b01) Dq_dqm [15 : 0] = Bank1 [{Row, Col}]; if (Bank == 2'b10) Dq_dqm [15 : 0] = Bank2 [{Row, Col}]; if (Bank == 2'b11) Dq_dqm [15 : 0] = Bank3 [{Row, Col}]; // Dqm operation if (Dqm_reg0[0] == 1'b1) Dq_dqm [ 7 : 0] = 8'bz; // Display result Dq_reg [15 : 0] = #tAC Dq_dqm [15 : 0]; if (Dqm_reg0 == 1'b1) begin if (Debug) $display("at time %t READ : Bank = %d Row = %d, Col = %d, Data = Hi-Z due to DQM", $time, Bank, Row, Col); end else begin if (Debug) $display("at time %t READ : Bank = %d Row = %d, Col = %d, Data = %h, Dqm = %b", $time, Bank, Row, Col, Dq_reg, Dqm_reg0); end // Advance burst counter subroutine Burst; end end // Write with Auto Precharge Calculation // The device start internal precharge: // 1. tWR Clock after last burst // and 2. Meet minimum tRAS requirement // or 3. Interrupt by a Read or Write (with or without AutoPrecharge) always @ (WR_counter[0]) begin if ((Auto_precharge[0] == 1'b1) && (Write_precharge[0] == 1'b1)) begin if ((($time - RAS_chk0 >= tRAS) && // Case 2 (((Burst_length_1 == 1'b1 || Write_burst_mode == 1'b1) && Count_precharge [0] >= 1) || // Case 1 (Burst_length_2 == 1'b1 && Count_precharge [0] >= 2) || (Burst_length_4 == 1'b1 && Count_precharge [0] >= 4) || (Burst_length_8 == 1'b1 && Count_precharge [0] >= 8))) || (RW_interrupt_write[0] == 1'b1 && WR_counter[0] >= 2)) begin // Case 3 (stop count when interrupt) Auto_precharge[0] = 1'b0; Write_precharge[0] = 1'b0; RW_interrupt_write[0] = 1'b0; #tWRa; // Wait for tWR Pc_b0 = 1'b1; Act_b0 = 1'b0; RP_chk0 = $time; if (Debug) $display ("at time %t NOTE : Start Internal Auto Precharge for Bank 0", $time); end end end always @ (WR_counter[1]) begin if ((Auto_precharge[1] == 1'b1) && (Write_precharge[1] == 1'b1)) begin if ((($time - RAS_chk1 >= tRAS) && (((Burst_length_1 == 1'b1 || Write_burst_mode == 1'b1) && Count_precharge [1] >= 1) || (Burst_length_2 == 1'b1 && Count_precharge [1] >= 2) || (Burst_length_4 == 1'b1 && Count_precharge [1] >= 4) || (Burst_length_8 == 1'b1 && Count_precharge [1] >= 8))) || (RW_interrupt_write[1] == 1'b1 && WR_counter[1] >= 2)) begin Auto_precharge[1] = 1'b0; Write_precharge[1] = 1'b0; RW_interrupt_write[1] = 1'b0; #tWRa; // Wait for tWR Pc_b1 = 1'b1; Act_b1 = 1'b0; RP_chk1 = $time; if (Debug) $display ("at time %t NOTE : Start Internal Auto Precharge for Bank 1", $time); end end end always @ (WR_counter[2]) begin if ((Auto_precharge[2] == 1'b1) && (Write_precharge[2] == 1'b1)) begin if ((($time - RAS_chk2 >= tRAS) && (((Burst_length_1 == 1'b1 || Write_burst_mode == 1'b1) && Count_precharge [2] >= 1) || (Burst_length_2 == 1'b1 && Count_precharge [2] >= 2) || (Burst_length_4 == 1'b1 && Count_precharge [2] >= 4) || (Burst_length_8 == 1'b1 && Count_precharge [2] >= 8))) || (RW_interrupt_write[2] == 1'b1 && WR_counter[2] >= 2)) begin Auto_precharge[2] = 1'b0; Write_precharge[2] = 1'b0; RW_interrupt_write[2] = 1'b0; #tWRa; // Wait for tWR Pc_b2 = 1'b1; Act_b2 = 1'b0; RP_chk2 = $time; if (Debug) $display ("at time %t NOTE : Start Internal Auto Precharge for Bank 2", $time); end end end always @ (WR_counter[3]) begin if ((Auto_precharge[3] == 1'b1) && (Write_precharge[3] == 1'b1)) begin if ((($time - RAS_chk3 >= tRAS) && (((Burst_length_1 == 1'b1 || Write_burst_mode == 1'b1) && Count_precharge [3] >= 1) || (Burst_length_2 == 1'b1 && Count_precharge [3] >= 2) || (Burst_length_4 == 1'b1 && Count_precharge [3] >= 4) || (Burst_length_8 == 1'b1 && Count_precharge [3] >= 8))) || (RW_interrupt_write[3] == 1'b1 && WR_counter[3] >= 2)) begin Auto_precharge[3] = 1'b0; Write_precharge[3] = 1'b0; RW_interrupt_write[3] = 1'b0; #tWRa; // Wait for tWR Pc_b3 = 1'b1; Act_b3 = 1'b0; RP_chk3 = $time; if (Debug) $display ("at time %t NOTE : Start Internal Auto Precharge for Bank 3", $time); end end end task Burst; begin // Advance Burst Counter Burst_counter = Burst_counter + 1; // Burst Type if (Mode_reg[3] == 1'b0) begin // Sequential Burst Col_temp = Col + 1; end else if (Mode_reg[3] == 1'b1) begin // Interleaved Burst Col_temp[2] = Burst_counter[2] ^ Col_brst[2]; Col_temp[1] = Burst_counter[1] ^ Col_brst[1]; Col_temp[0] = Burst_counter[0] ^ Col_brst[0]; end // Burst Length if (Burst_length_2) begin // Burst Length = 2 Col [0] = Col_temp [0]; end else if (Burst_length_4) begin // Burst Length = 4 Col [1 : 0] = Col_temp [1 : 0]; end else if (Burst_length_8) begin // Burst Length = 8 Col [2 : 0] = Col_temp [2 : 0]; end else begin // Burst Length = FULL Col = Col_temp; end // Burst Read Single Write if (Write_burst_mode == 1'b1) begin Data_in_enable = 1'b0; end // Data Counter if (Burst_length_1 == 1'b1) begin if (Burst_counter >= 1) begin Data_in_enable = 1'b0; Data_out_enable = 1'b0; end end else if (Burst_length_2 == 1'b1) begin if (Burst_counter >= 2) begin Data_in_enable = 1'b0; Data_out_enable = 1'b0; end end else if (Burst_length_4 == 1'b1) begin if (Burst_counter >= 4) begin Data_in_enable = 1'b0; Data_out_enable = 1'b0; end end else if (Burst_length_8 == 1'b1) begin if (Burst_counter >= 8) begin Data_in_enable = 1'b0; Data_out_enable = 1'b0; end end end endtask // Timing Parameters for -75 (PC133) and CAS Latency = 2 specify specparam tAH = 0.8, // Addr, Ba Hold Time tAS = 1.5, // Addr, Ba Setup Time tCH = 2.5, // Clock High-Level Width tCL = 2.5, // Clock Low-Level Width tCK = 10, // Clock Cycle Time tDH = 0.8, // Data-in Hold Time tDS = 1.5, // Data-in Setup Time tCKH = 0.8, // CKE Hold Time tCKS = 1.5, // CKE Setup Time tCMH = 0.8, // CS#, RAS#, CAS#, WE#, DQM# Hold Time tCMS = 1.5; // CS#, RAS#, CAS#, WE#, DQM# Setup Time $width (posedge Clk, tCH); $width (negedge Clk, tCL); $period (negedge Clk, tCK); $period (posedge Clk, tCK); $setuphold(posedge Clk, Cke, tCKS, tCKH); $setuphold(posedge Clk, Cs_n, tCMS, tCMH); $setuphold(posedge Clk, Cas_n, tCMS, tCMH); $setuphold(posedge Clk, Ras_n, tCMS, tCMH); $setuphold(posedge Clk, We_n, tCMS, tCMH); $setuphold(posedge Clk, Addr, tAS, tAH); $setuphold(posedge Clk, Ba, tAS, tAH); $setuphold(posedge Clk, Dqm, tCMS, tCMH); $setuphold(posedge Dq_chk, Dq, tDS, tDH); endspecify endmodule