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/**************************************************************************************** * * Disclaimer This software code and all associated documentation, comments or other * of Warranty: information (collectively "Software") is provided "AS IS" without * warranty of any kind. MICRON TECHNOLOGY, INC. ("MTI") EXPRESSLY * DISCLAIMS ALL WARRANTIES EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED * TO, NONINFRINGEMENT OF THIRD PARTY RIGHTS, AND ANY IMPLIED WARRANTIES * OF MERCHANTABILITY OR FITNESS FOR ANY PARTICULAR PURPOSE. MTI DOES NOT * WARRANT THAT THE SOFTWARE WILL MEET YOUR REQUIREMENTS, OR THAT THE * OPERATION OF THE SOFTWARE WILL BE UNINTERRUPTED OR ERROR-FREE. * FURTHERMORE, MTI DOES NOT MAKE ANY REPRESENTATIONS REGARDING THE USE OR * THE RESULTS OF THE USE OF THE SOFTWARE IN TERMS OF ITS CORRECTNESS, * ACCURACY, RELIABILITY, OR OTHERWISE. THE ENTIRE RISK ARISING OUT OF USE * OR PERFORMANCE OF THE SOFTWARE REMAINS WITH YOU. IN NO EVENT SHALL MTI, * ITS AFFILIATED COMPANIES OR THEIR SUPPLIERS BE LIABLE FOR ANY DIRECT, * INDIRECT, CONSEQUENTIAL, INCIDENTAL, OR SPECIAL DAMAGES (INCLUDING, * WITHOUT LIMITATION, DAMAGES FOR LOSS OF PROFITS, BUSINESS INTERRUPTION, * OR LOSS OF INFORMATION) ARISING OUT OF YOUR USE OF OR INABILITY TO USE * THE SOFTWARE, EVEN IF MTI HAS BEEN ADVISED OF THE POSSIBILITY OF SUCH * DAMAGES. Because some jurisdictions prohibit the exclusion or * limitation of liability for consequential or incidental damages, the * above limitation may not apply to you. * * Copyright 2003 Micron Technology, Inc. All rights reserved. * ****************************************************************************************/ // Parameters current with 512Mb datasheet rev N // Timing parameters based on Speed Grade // SYMBOL UNITS DESCRIPTION // ------ ----- ----------- `ifdef sg187E parameter TCK_MIN = 1875; // tCK ps Minimum Clock Cycle Time parameter TJIT_PER = 90; // tJIT(per) ps Period JItter parameter TJIT_DUTY = 75; // tJIT(duty) ps Half Period Jitter parameter TJIT_CC = 180; // tJIT(cc) ps Cycle to Cycle jitter parameter TERR_2PER = 132; // tERR(nper) ps Accumulated Error (2-cycle) parameter TERR_3PER = 157; // tERR(nper) ps Accumulated Error (3-cycle) parameter TERR_4PER = 175; // tERR(nper) ps Accumulated Error (4-cycle) parameter TERR_5PER = 188; // tERR(nper) ps Accumulated Error (5-cycle) parameter TERR_N1PER = 250; // tERR(nper) ps Accumulated Error (6-10-cycle) parameter TERR_N2PER = 425; // tERR(nper) ps Accumulated Error (11-50-cycle) parameter TQHS = 250; // tQHS ps Data hold skew factor parameter TAC = 350; // tAC ps DQ output access time from CK/CK# parameter TDS = 0; // tDS ps DQ and DM input setup time relative to DQS parameter TDH = 75; // tDH ps DQ and DM input hold time relative to DQS parameter TDQSCK = 300; // tDQSCK ps DQS output access time from CK/CK# parameter TDQSQ = 175; // tDQSQ ps DQS-DQ skew, DQS to last DQ valid, per group, per access parameter TIS = 125; // tIS ps Input Setup Time parameter TIH = 200; // tIH ps Input Hold Time parameter TRC = 54000; // tRC ps Active to Active/Auto Refresh command time parameter TRCD = 13125; // tRCD ps Active to Read/Write command time parameter TWTR = 7500; // tWTR ps Write to Read command delay parameter TRP = 13125; // tRP ps Precharge command period parameter TRPA = 13125; // tRPA ps Precharge All period parameter TXARDS = 10; // tXARDS tCK Exit low power active power down to a read command parameter TXARD = 3; // tXARD tCK Exit active power down to a read command parameter TXP = 3; // tXP tCK Exit power down to a non-read command parameter TANPD = 4; // tANPD tCK ODT to power-down entry latency parameter TAXPD = 11; // tAXPD tCK ODT power-down exit latency parameter CL_TIME = 13125; // CL ps Minimum CAS Latency `else `ifdef sg25E parameter TCK_MIN = 2500; // tCK ps Minimum Clock Cycle Time parameter TJIT_PER = 100; // tJIT(per) ps Period JItter parameter TJIT_DUTY = 100; // tJIT(duty) ps Half Period Jitter parameter TJIT_CC = 200; // tJIT(cc) ps Cycle to Cycle jitter parameter TERR_2PER = 150; // tERR(nper) ps Accumulated Error (2-cycle) parameter TERR_3PER = 175; // tERR(nper) ps Accumulated Error (3-cycle) parameter TERR_4PER = 200; // tERR(nper) ps Accumulated Error (4-cycle) parameter TERR_5PER = 200; // tERR(nper) ps Accumulated Error (5-cycle) parameter TERR_N1PER = 300; // tERR(nper) ps Accumulated Error (6-10-cycle) parameter TERR_N2PER = 450; // tERR(nper) ps Accumulated Error (11-50-cycle) parameter TQHS = 300; // tQHS ps Data hold skew factor parameter TAC = 400; // tAC ps DQ output access time from CK/CK# parameter TDS = 50; // tDS ps DQ and DM input setup time relative to DQS parameter TDH = 125; // tDH ps DQ and DM input hold time relative to DQS parameter TDQSCK = 350; // tDQSCK ps DQS output access time from CK/CK# parameter TDQSQ = 200; // tDQSQ ps DQS-DQ skew, DQS to last DQ valid, per group, per access parameter TIS = 175; // tIS ps Input Setup Time parameter TIH = 250; // tIH ps Input Hold Time parameter TRC = 55000; // tRC ps Active to Active/Auto Refresh command time parameter TRCD = 12500; // tRCD ps Active to Read/Write command time parameter TWTR = 7500; // tWTR ps Write to Read command delay parameter TRP = 12500; // tRP ps Precharge command period parameter TRPA = 12500; // tRPA ps Precharge All period parameter TXARDS = 8; // tXARDS tCK Exit low power active power down to a read command parameter TXARD = 2; // tXARD tCK Exit active power down to a read command parameter TXP = 2; // tXP tCK Exit power down to a non-read command parameter TANPD = 3; // tANPD tCK ODT to power-down entry latency parameter TAXPD = 10; // tAXPD tCK ODT power-down exit latency parameter CL_TIME = 12500; // CL ps Minimum CAS Latency `else `ifdef sg25 parameter TCK_MIN = 2500; // tCK ps Minimum Clock Cycle Time parameter TJIT_PER = 100; // tJIT(per) ps Period JItter parameter TJIT_DUTY = 100; // tJIT(duty) ps Half Period Jitter parameter TJIT_CC = 200; // tJIT(cc) ps Cycle to Cycle jitter parameter TERR_2PER = 150; // tERR(nper) ps Accumulated Error (2-cycle) parameter TERR_3PER = 175; // tERR(nper) ps Accumulated Error (3-cycle) parameter TERR_4PER = 200; // tERR(nper) ps Accumulated Error (4-cycle) parameter TERR_5PER = 200; // tERR(nper) ps Accumulated Error (5-cycle) parameter TERR_N1PER = 300; // tERR(nper) ps Accumulated Error (6-10-cycle) parameter TERR_N2PER = 450; // tERR(nper) ps Accumulated Error (11-50-cycle) parameter TQHS = 300; // tQHS ps Data hold skew factor parameter TAC = 400; // tAC ps DQ output access time from CK/CK# parameter TDS = 50; // tDS ps DQ and DM input setup time relative to DQS parameter TDH = 125; // tDH ps DQ and DM input hold time relative to DQS parameter TDQSCK = 350; // tDQSCK ps DQS output access time from CK/CK# parameter TDQSQ = 200; // tDQSQ ps DQS-DQ skew, DQS to last DQ valid, per group, per access parameter TIS = 175; // tIS ps Input Setup Time parameter TIH = 250; // tIH ps Input Hold Time parameter TRC = 55000; // tRC ps Active to Active/Auto Refresh command time parameter TRCD = 15000; // tRCD ps Active to Read/Write command time parameter TWTR = 7500; // tWTR ps Write to Read command delay parameter TRP = 15000; // tRP ps Precharge command period parameter TRPA = 15000; // tRPA ps Precharge All period parameter TXARDS = 8; // tXARDS tCK Exit low power active power down to a read command parameter TXARD = 2; // tXARD tCK Exit active power down to a read command parameter TXP = 2; // tXP tCK Exit power down to a non-read command parameter TANPD = 3; // tANPD tCK ODT to power-down entry latency parameter TAXPD = 10; // tAXPD tCK ODT power-down exit latency parameter CL_TIME = 15000; // CL ps Minimum CAS Latency `else `ifdef sg3E parameter TCK_MIN = 3000; // tCK ps Minimum Clock Cycle Time parameter TJIT_PER = 125; // tJIT(per) ps Period JItter parameter TJIT_DUTY = 125; // tJIT(duty) ps Half Period Jitter parameter TJIT_CC = 250; // tJIT(cc) ps Cycle to Cycle jitter parameter TERR_2PER = 175; // tERR(nper) ps Accumulated Error (2-cycle) parameter TERR_3PER = 225; // tERR(nper) ps Accumulated Error (3-cycle) parameter TERR_4PER = 250; // tERR(nper) ps Accumulated Error (4-cycle) parameter TERR_5PER = 250; // tERR(nper) ps Accumulated Error (5-cycle) parameter TERR_N1PER = 350; // tERR(nper) ps Accumulated Error (6-10-cycle) parameter TERR_N2PER = 450; // tERR(nper) ps Accumulated Error (11-50-cycle) parameter TQHS = 340; // tQHS ps Data hold skew factor parameter TAC = 450; // tAC ps DQ output access time from CK/CK# parameter TDS = 100; // tDS ps DQ and DM input setup time relative to DQS parameter TDH = 175; // tDH ps DQ and DM input hold time relative to DQS parameter TDQSCK = 400; // tDQSCK ps DQS output access time from CK/CK# parameter TDQSQ = 240; // tDQSQ ps DQS-DQ skew, DQS to last DQ valid, per group, per access parameter TIS = 200; // tIS ps Input Setup Time parameter TIH = 275; // tIH ps Input Hold Time parameter TRC = 54000; // tRC ps Active to Active/Auto Refresh command time parameter TRCD = 12000; // tRCD ps Active to Read/Write command time parameter TWTR = 7500; // tWTR ps Write to Read command delay parameter TRP = 12000; // tRP ps Precharge command period parameter TRPA = 12000; // tRPA ps Precharge All period parameter TXARDS = 7; // tXARDS tCK Exit low power active power down to a read command parameter TXARD = 2; // tXARD tCK Exit active power down to a read command parameter TXP = 2; // tXP tCK Exit power down to a non-read command parameter TANPD = 3; // tANPD tCK ODT to power-down entry latency parameter TAXPD = 8; // tAXPD tCK ODT power-down exit latency parameter CL_TIME = 12000; // CL ps Minimum CAS Latency `else `ifdef sg3 parameter TCK_MIN = 3000; // tCK ps Minimum Clock Cycle Time parameter TJIT_PER = 125; // tJIT(per) ps Period JItter parameter TJIT_DUTY = 125; // tJIT(duty) ps Half Period Jitter parameter TJIT_CC = 250; // tJIT(cc) ps Cycle to Cycle jitter parameter TERR_2PER = 175; // tERR(nper) ps Accumulated Error (2-cycle) parameter TERR_3PER = 225; // tERR(nper) ps Accumulated Error (3-cycle) parameter TERR_4PER = 250; // tERR(nper) ps Accumulated Error (4-cycle) parameter TERR_5PER = 250; // tERR(nper) ps Accumulated Error (5-cycle) parameter TERR_N1PER = 350; // tERR(nper) ps Accumulated Error (6-10-cycle) parameter TERR_N2PER = 450; // tERR(nper) ps Accumulated Error (11-50-cycle) parameter TQHS = 340; // tQHS ps Data hold skew factor parameter TAC = 450; // tAC ps DQ output access time from CK/CK# parameter TDS = 100; // tDS ps DQ and DM input setup time relative to DQS parameter TDH = 175; // tDH ps DQ and DM input hold time relative to DQS parameter TDQSCK = 400; // tDQSCK ps DQS output access time from CK/CK# parameter TDQSQ = 240; // tDQSQ ps DQS-DQ skew, DQS to last DQ valid, per group, per access parameter TIS = 200; // tIS ps Input Setup Time parameter TIH = 275; // tIH ps Input Hold Time parameter TRC = 55000; // tRC ps Active to Active/Auto Refresh command time parameter TRCD = 15000; // tRCD ps Active to Read/Write command time parameter TWTR = 7500; // tWTR ps Write to Read command delay parameter TRP = 15000; // tRP ps Precharge command period parameter TRPA = 15000; // tRPA ps Precharge All period parameter TXARDS = 7; // tXARDS tCK Exit low power active power down to a read command parameter TXARD = 2; // tXARD tCK Exit active power down to a read command parameter TXP = 2; // tXP tCK Exit power down to a non-read command parameter TANPD = 3; // tANPD tCK ODT to power-down entry latency parameter TAXPD = 8; // tAXPD tCK ODT power-down exit latency parameter CL_TIME = 15000; // CL ps Minimum CAS Latency `else `ifdef sg37E parameter TCK_MIN = 3750; // tCK ps Minimum Clock Cycle Time parameter TJIT_PER = 125; // tJIT(per) ps Period JItter parameter TJIT_DUTY = 125; // tJIT(duty) ps Half Period Jitter parameter TJIT_CC = 250; // tJIT(cc) ps Cycle to Cycle jitter parameter TERR_2PER = 175; // tERR(nper) ps Accumulated Error (2-cycle) parameter TERR_3PER = 225; // tERR(nper) ps Accumulated Error (3-cycle) parameter TERR_4PER = 250; // tERR(nper) ps Accumulated Error (4-cycle) parameter TERR_5PER = 250; // tERR(nper) ps Accumulated Error (5-cycle) parameter TERR_N1PER = 350; // tERR(nper) ps Accumulated Error (6-10-cycle) parameter TERR_N2PER = 450; // tERR(nper) ps Accumulated Error (11-50-cycle) parameter TQHS = 400; // tQHS ps Data hold skew factor parameter TAC = 500; // tAC ps DQ output access time from CK/CK# parameter TDS = 100; // tDS ps DQ and DM input setup time relative to DQS parameter TDH = 225; // tDH ps DQ and DM input hold time relative to DQS parameter TDQSCK = 450; // tDQSCK ps DQS output access time from CK/CK# parameter TDQSQ = 300; // tDQSQ ps DQS-DQ skew, DQS to last DQ valid, per group, per access parameter TIS = 250; // tIS ps Input Setup Time parameter TIH = 375; // tIH ps Input Hold Time parameter TRC = 55000; // tRC ps Active to Active/Auto Refresh command time parameter TRCD = 15000; // tRCD ps Active to Read/Write command time parameter TWTR = 7500; // tWTR ps Write to Read command delay parameter TRP = 15000; // tRP ps Precharge command period parameter TRPA = 15000; // tRPA ps Precharge All period parameter TXARDS = 6; // tXARDS tCK Exit low power active power down to a read command parameter TXARD = 2; // tXARD tCK Exit active power down to a read command parameter TXP = 2; // tXP tCK Exit power down to a non-read command parameter TANPD = 3; // tANPD tCK ODT to power-down entry latency parameter TAXPD = 8; // tAXPD tCK ODT power-down exit latency parameter CL_TIME = 15000; // CL ps Minimum CAS Latency `else `define sg5E parameter TCK_MIN = 5000; // tCK ps Minimum Clock Cycle Time parameter TJIT_PER = 125; // tJIT(per) ps Period JItter parameter TJIT_DUTY = 150; // tJIT(duty) ps Half Period Jitter parameter TJIT_CC = 250; // tJIT(cc) ps Cycle to Cycle jitter parameter TERR_2PER = 175; // tERR(nper) ps Accumulated Error (2-cycle) parameter TERR_3PER = 225; // tERR(nper) ps Accumulated Error (3-cycle) parameter TERR_4PER = 250; // tERR(nper) ps Accumulated Error (4-cycle) parameter TERR_5PER = 250; // tERR(nper) ps Accumulated Error (5-cycle) parameter TERR_N1PER = 350; // tERR(nper) ps Accumulated Error (6-10-cycle) parameter TERR_N2PER = 450; // tERR(nper) ps Accumulated Error (11-50-cycle) parameter TQHS = 450; // tQHS ps Data hold skew factor parameter TAC = 600; // tAC ps DQ output access time from CK/CK# parameter TDS = 150; // tDS ps DQ and DM input setup time relative to DQS parameter TDH = 275; // tDH ps DQ and DM input hold time relative to DQS parameter TDQSCK = 500; // tDQSCK ps DQS output access time from CK/CK# parameter TDQSQ = 350; // tDQSQ ps DQS-DQ skew, DQS to last DQ valid, per group, per access parameter TIS = 350; // tIS ps Input Setup Time parameter TIH = 475; // tIH ps Input Hold Time parameter TRC = 55000; // tRC ps Active to Active/Auto Refresh command time parameter TRCD = 15000; // tRCD ps Active to Read/Write command time parameter TWTR = 10000; // tWTR ps Write to Read command delay parameter TRP = 15000; // tRP ps Precharge command period parameter TRPA = 15000; // tRPA ps Precharge All period parameter TXARDS = 6; // tXARDS tCK Exit low power active power down to a read command parameter TXARD = 2; // tXARD tCK Exit active power down to a read command parameter TXP = 2; // tXP tCK Exit power down to a non-read command parameter TANPD = 3; // tANPD tCK ODT to power-down entry latency parameter TAXPD = 8; // tAXPD tCK ODT power-down exit latency parameter CL_TIME = 15000; // CL ps Minimum CAS Latency `endif `endif `endif `endif `endif `endif `ifdef x16 `ifdef sg187E parameter TFAW = 45000; // tFAW ps Four Bank Activate window `else `ifdef sg25E parameter TFAW = 45000; // tFAW ps Four Bank Activate window `else `ifdef sg25 parameter TFAW = 45000; // tFAW ps Four Bank Activate window `else // sg3E, sg3, sg37E, sg5E parameter TFAW = 50000; // tFAW ps Four Bank Activate window `endif `endif `endif `else // x4, x8 `ifdef sg187E parameter TFAW = 35000; // tFAW ps Four Bank Activate window `else `ifdef sg25E parameter TFAW = 35000; // tFAW ps Four Bank Activate window `else `ifdef sg25 parameter TFAW = 35000; // tFAW ps Four Bank Activate window `else // sg3E, sg3, sg37E, sg5E parameter TFAW = 37500; // tFAW ps Four Bank Activate window `endif `endif `endif `endif // Timing Parameters // Mode Register parameter AL_MIN = 0; // AL tCK Minimum Additive Latency parameter AL_MAX = 6; // AL tCK Maximum Additive Latency parameter CL_MIN = 3; // CL tCK Minimum CAS Latency parameter CL_MAX = 7; // CL tCK Maximum CAS Latency parameter WR_MIN = 2; // WR tCK Minimum Write Recovery parameter WR_MAX = 8; // WR tCK Maximum Write Recovery parameter BL_MIN = 4; // BL tCK Minimum Burst Length parameter BL_MAX = 8; // BL tCK Minimum Burst Length // Clock parameter TCK_MAX = 8000; // tCK ps Maximum Clock Cycle Time parameter TCH_MIN = 0.48; // tCH tCK Minimum Clock High-Level Pulse Width parameter TCH_MAX = 0.52; // tCH tCK Maximum Clock High-Level Pulse Width parameter TCL_MIN = 0.48; // tCL tCK Minimum Clock Low-Level Pulse Width parameter TCL_MAX = 0.52; // tCL tCK Maximum Clock Low-Level Pulse Width // Data parameter TLZ = TAC; // tLZ ps Data-out low-impedance window from CK/CK# parameter THZ = TAC; // tHZ ps Data-out high impedance window from CK/CK# parameter TDIPW = 0.35; // tDIPW tCK DQ and DM input Pulse Width // Data Strobe parameter TDQSH = 0.35; // tDQSH tCK DQS input High Pulse Width parameter TDQSL = 0.35; // tDQSL tCK DQS input Low Pulse Width parameter TDSS = 0.20; // tDSS tCK DQS falling edge to CLK rising (setup time) parameter TDSH = 0.20; // tDSH tCK DQS falling edge from CLK rising (hold time) parameter TWPRE = 0.35; // tWPRE tCK DQS Write Preamble parameter TWPST = 0.40; // tWPST tCK DQS Write Postamble parameter TDQSS = 0.25; // tDQSS tCK Rising clock edge to DQS/DQS# latching transition // Command and Address parameter TIPW = 0.6; // tIPW tCK Control and Address input Pulse Width parameter TCCD = 2; // tCCD tCK Cas to Cas command delay parameter TRAS_MIN = 40000; // tRAS ps Minimum Active to Precharge command time parameter TRAS_MAX =70000000; // tRAS ps Maximum Active to Precharge command time parameter TRTP = 7500; // tRTP ps Read to Precharge command delay parameter TWR = 15000; // tWR ps Write recovery time parameter TMRD = 2; // tMRD tCK Load Mode Register command cycle time parameter TDLLK = 200; // tDLLK tCK DLL locking time // Refresh parameter TRFC_MIN = 105000; // tRFC ps Refresh to Refresh Command interval minimum value parameter TRFC_MAX =70000000; // tRFC ps Refresh to Refresh Command Interval maximum value // Self Refresh parameter TXSNR = TRFC_MIN + 10000; // tXSNR ps Exit self refesh to a non-read command parameter TXSRD = 200; // tXSRD tCK Exit self refresh to a read command parameter TISXR = TIS; // tISXR ps CKE setup time during self refresh exit. // ODT parameter TAOND = 2; // tAOND tCK ODT turn-on delay parameter TAOFD = 2.5; // tAOFD tCK ODT turn-off delay parameter TAONPD = 2000; // tAONPD ps ODT turn-on (precharge power-down mode) parameter TAOFPD = 2000; // tAOFPD ps ODT turn-off (precharge power-down mode) parameter TMOD = 12000; // tMOD ps ODT enable in EMR to ODT pin transition // Power Down parameter TCKE = 3; // tCKE tCK CKE minimum high or low pulse width // Size Parameters based on Part Width `ifdef x4 parameter ADDR_BITS = 14; // Address Bits parameter ROW_BITS = 14; // Number of Address bits parameter COL_BITS = 11; // Number of Column bits parameter DM_BITS = 1; // Number of Data Mask bits parameter DQ_BITS = 4; // Number of Data bits parameter DQS_BITS = 1; // Number of Dqs bits parameter TRRD = 7500; // tRRD Active bank a to Active bank b command time `else `ifdef x8 parameter ADDR_BITS = 14; // Address Bits parameter ROW_BITS = 14; // Number of Address bits parameter COL_BITS = 10; // Number of Column bits parameter DM_BITS = 1; // Number of Data Mask bits parameter DQ_BITS = 8; // Number of Data bits parameter DQS_BITS = 1; // Number of Dqs bits parameter TRRD = 7500; // tRRD Active bank a to Active bank b command time `else `define x16 parameter ADDR_BITS = 13; // Address Bits parameter ROW_BITS = 13; // Number of Address bits parameter COL_BITS = 10; // Number of Column bits parameter DM_BITS = 2; // Number of Data Mask bits parameter DQ_BITS = 16; // Number of Data bits parameter DQS_BITS = 2; // Number of Dqs bits parameter TRRD = 10000; // tRRD Active bank a to Active bank b command time `endif `endif `ifdef QUAD_RANK `define DUAL_RANK // also define DUAL_RANK parameter CS_BITS = 4; // Number of Chip Select Bits parameter RANKS = 4; // Number of Chip Select Bits `else `ifdef DUAL_RANK parameter CS_BITS = 2; // Number of Chip Select Bits parameter RANKS = 2; // Number of Chip Select Bits `else parameter CS_BITS = 2; // Number of Chip Select Bits parameter RANKS = 1; // Number of Chip Select Bits `endif `endif // Size Parameters parameter BA_BITS = 2; // Set this parmaeter to control how many Bank Address bits parameter MEM_BITS = 10; // Number of write data bursts can be stored in memory. The default is 2^10=1024. parameter AP = 10; // the address bit that controls auto-precharge and precharge-all parameter BL_BITS = 3; // the number of bits required to count to MAX_BL parameter BO_BITS = 2; // the number of Burst Order Bits // Simulation parameters parameter STOP_ON_ERROR = 1; // If set to 1, the model will halt on command sequence/major errors parameter DEBUG = 1; // Turn on Debug messages parameter BUS_DELAY = 0; // delay in nanoseconds parameter RANDOM_OUT_DELAY = 0; // If set to 1, the model will put a random amount of delay on DQ/DQS during reads parameter RANDOM_SEED = 711689044; //seed value for random generator. parameter RDQSEN_PRE = 2; // DQS driving time prior to first read strobe parameter RDQSEN_PST = 1; // DQS driving time after last read strobe parameter RDQS_PRE = 2; // DQS low time prior to first read strobe parameter RDQS_PST = 1; // DQS low time after last valid read strobe parameter RDQEN_PRE = 0; // DQ/DM driving time prior to first read data parameter RDQEN_PST = 0; // DQ/DM driving time after last read data parameter WDQS_PRE = 1; // DQS half clock periods prior to first write strobe parameter WDQS_PST = 1; // DQS half clock periods after last valid write strobe