// --------------------------------------------------------------------
// >>>>>>>>>>>>>>>>>>>>>>>>> COPYRIGHT NOTICE <<<<<<<<<<<<<<<<<<<<<<<<<
// --------------------------------------------------------------------
// Copyright (c) 2004 by Lattice Semiconductor Corporation
// --------------------------------------------------------------------
//
// Permission:
//
//   Lattice Semiconductor grants permission to use this code for use
//   in synthesis for any Lattice programmable logic product.  Other
//   use of this code, including the selling or duplication of any
//   portion is strictly prohibited.
//
// Disclaimer:
//
//   This VHDL or Verilog source code is intended as a design reference
//   which illustrates how these types of functions can be implemented.
//   It is the user's responsibility to verify their design for
//   consistency and functionality through the use of formal
//   verification methods.  Lattice Semiconductor provides no warranty
//   regarding the use or functionality of this code.
//
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//
//                     Lattice Semiconductor Corporation
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//                     TEL: 1-800-Lattice (USA and Canada)
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//                     web: http://www.latticesemi.com/
//                     email: techsupport@latticesemi.com
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// --------------------------------------------------------------------
//
// This file contains the parameters used in the SDR SDRAM controller
// reference design.
//
// --------------------------------------------------------------------
//
// Revision History :
// --------------------------------------------------------------------
//   Ver  :| Author            :| Mod. Date :| Changes Made:
//   V0.1 :|                   :| 06/29/04  :| Pre-Release
// --------------------------------------------------------------------

parameter tDLY = 2; // 2ns delay for simulation purpose

//---------------------------------------------------------------------
// SDRAM mode register definition
//

// Write Burst Mode
parameter Programmed_Length = 1'b0;
parameter Single_Access     = 1'b1;

// Operation Mode
parameter Standard          = 2'b00;

// CAS Latency
parameter Latency_2         = 3'b010;
parameter Latency_3         = 3'b011;

// Burst Type
parameter Sequential        = 1'b0;
parameter Interleaved       = 1'b1;

// Burst Length
parameter Length_1          = 3'b000;
parameter Length_2          = 3'b001;
parameter Length_4          = 3'b010;
parameter Length_8          = 3'b011;

//---------------------------------------------------------------------
// User modifiable parameters
//

/****************************
* Mode register setting
****************************/

parameter MR_Write_Burst_Mode =    Programmed_Length;
                                // Single_Access;

parameter MR_Operation_Mode   =    Standard;

parameter MR_CAS_Latency      = // Latency_2;
                                   Latency_3;

parameter MR_Burst_Type       =    Sequential;
                                // Interleaved;

parameter MR_Burst_Length     = // Length_1;
                                // Length_2;
                                   Length_4;
                                // Length_8;

/****************************
* Bus width setting
****************************/

//
//           23 ......... 12     11 ....... 10      9 .........0
// sys_A  : MSB <-------------------------------------------> LSB
//
// Row    : RA_MSB <--> RA_LSB
// Bank   :                    BA_MSB <--> BA_LSB
// Column :                                       CA_MSB <--> CA_LSB
//

parameter RA_MSB = 22;
parameter RA_LSB = 11;

parameter BA_MSB = 10;
parameter BA_LSB =  9;

parameter CA_MSB =  8;
parameter CA_LSB =  0;

parameter SDR_BA_WIDTH =  2; // BA0,BA1
parameter SDR_A_WIDTH  = 12; // A0-A11

/****************************
* SDRAM AC timing spec
****************************/

parameter tCK  = 12;
parameter tMRD = 2*tCK;
parameter tRP  = 15;
parameter tRFC = 66;
parameter tRCD = 15;
parameter tWR  = tCK + 7;
parameter tDAL = tWR + tRP;

//---------------------------------------------------------------------
// Clock count definition for meeting SDRAM AC timing spec
//

parameter NUM_CLK_tMRD = tMRD/tCK;
parameter NUM_CLK_tRP  =  tRP/tCK;
parameter NUM_CLK_tRFC = tRFC/tCK;
parameter NUM_CLK_tRCD = tRCD/tCK;
parameter NUM_CLK_tDAL = tDAL/tCK;

// tDAL needs to be satisfied before the next sdram ACTIVE command can
// be issued. State c_tDAL of CMD_FSM is created for this purpose.
// However, states c_idle, c_ACTIVE and c_tRCD need to be taken into
// account because ACTIVE command will not be issued until CMD_FSM
// switch from c_ACTIVE to c_tRCD. NUM_CLK_WAIT is the version after
// the adjustment.
parameter NUM_CLK_WAIT = (NUM_CLK_tDAL < 3) ? 0 : NUM_CLK_tDAL - 3;

parameter NUM_CLK_CL    = (MR_CAS_Latency == Latency_2) ? 2 :
                          (MR_CAS_Latency == Latency_3) ? 3 :
                          2;  // default

parameter NUM_CLK_READ  = (MR_Burst_Length == Length_1) ? 1 :
                          (MR_Burst_Length == Length_2) ? 2 :
                          (MR_Burst_Length == Length_4) ? 4 :
                          (MR_Burst_Length == Length_8) ? 8 :
                          4; // default

parameter NUM_CLK_WRITE = (MR_Burst_Length == Length_1) ? 1 :
                          (MR_Burst_Length == Length_2) ? 2 :
                          (MR_Burst_Length == Length_4) ? 4 :
                          (MR_Burst_Length == Length_8) ? 8 :
                          4; // default

//---------------------------------------------------------------------
// INIT_FSM state variable assignments (gray coded)
//

parameter i_NOP   = 4'b0000;
parameter i_PRE   = 4'b0001;
parameter i_tRP   = 4'b0010;
parameter i_AR1   = 4'b0011;
parameter i_tRFC1 = 4'b0100;
parameter i_AR2   = 4'b0101;
parameter i_tRFC2 = 4'b0110;
parameter i_MRS   = 4'b0111;
parameter i_tMRD  = 4'b1000;
parameter i_ready = 4'b1001;

//---------------------------------------------------------------------
// CMD_FSM state variable assignments (gray coded)
//

parameter c_idle   = 4'b0000;
parameter c_tRCD   = 4'b0001;
parameter c_cl     = 4'b0010;
parameter c_rdata  = 4'b0011;
parameter c_wdata  = 4'b0100;
parameter c_tRFC   = 4'b0101;
parameter c_tDAL   = 4'b0110;
parameter c_ACTIVE = 4'b1000;
parameter c_READA  = 4'b1001;
parameter c_WRITEA = 4'b1010;
parameter c_AR     = 4'b1011;

//---------------------------------------------------------------------
// SDRAM commands (sdr_CSn, sdr_RASn, sdr_CASn, sdr_WEn)
//

parameter INHIBIT            = 4'b1111;
parameter NOP                = 4'b0111;
parameter ACTIVE             = 4'b0011;
parameter READ               = 4'b0101;
parameter WRITE              = 4'b0100;
parameter BURST_TERMINATE    = 4'b0110;
parameter PRECHARGE          = 4'b0010;
parameter AUTO_REFRESH       = 4'b0001;
parameter LOAD_MODE_REGISTER = 4'b0000;