path: root/MdePkg/Include/IndustryStandard/SdramSpdDdr4.h

/** @file
  This file contains definitions for SPD DDR4.

  Copyright (c) 2016, Intel Corporation. All rights reserved.<BR>
  SPDX-License-Identifier: BSD-2-Clause-Patent

  @par Revision Reference:
    - Serial Presence Detect (SPD) for DDR4 SDRAM Modules Document Release 4
      http://www.jedec.org/standards-documents/docs/spd412l-4
**/

#ifndef _SDRAM_SPD_DDR4_H_
#define _SDRAM_SPD_DDR4_H_

#pragma pack (push, 1)

typedef union {
  struct {
    UINT8  BytesUsed                           :  4; ///< Bits 3:0
    UINT8  BytesTotal                          :  3; ///< Bits 6:4
    UINT8  CrcCoverage                         :  1; ///< Bits 7:7
  } Bits;
  UINT8  Data;
} SPD4_DEVICE_DESCRIPTION_STRUCT;

typedef union {
  struct {
    UINT8  Minor                               :  4; ///< Bits 3:0
    UINT8  Major                               :  4; ///< Bits 7:4
  } Bits;
  UINT8  Data;
} SPD4_REVISION_STRUCT;

typedef union {
  struct {
    UINT8  Type                                :  8; ///< Bits 7:0
  } Bits;
  UINT8  Data;
} SPD4_DRAM_DEVICE_TYPE_STRUCT;

typedef union {
  struct {
    UINT8  ModuleType                          :  4; ///< Bits 3:0
    UINT8  HybridMedia                         :  3; ///< Bits 6:4
    UINT8  Hybrid                              :  1; ///< Bits 7:7
  } Bits;
  UINT8  Data;
} SPD4_MODULE_TYPE_STRUCT;

typedef union {
  struct {
    UINT8  Density                             :  4; ///< Bits 3:0
    UINT8  BankAddress                         :  2; ///< Bits 5:4
    UINT8  BankGroup                           :  2; ///< Bits 7:6
  } Bits;
  UINT8  Data;
} SPD4_SDRAM_DENSITY_BANKS_STRUCT;

typedef union {
  struct {
    UINT8  ColumnAddress                       :  3; ///< Bits 2:0
    UINT8  RowAddress                          :  3; ///< Bits 5:3
    UINT8  Reserved                            :  2; ///< Bits 7:6
  } Bits;
  UINT8  Data;
} SPD4_SDRAM_ADDRESSING_STRUCT;

typedef union {
  struct {
    UINT8  SignalLoading                       :  2; ///< Bits 1:0
    UINT8  Reserved                            :  2; ///< Bits 3:2
    UINT8  DieCount                            :  3; ///< Bits 6:4
    UINT8  SdramPackageType                    :  1; ///< Bits 7:7
  } Bits;
  UINT8  Data;
} SPD4_PRIMARY_SDRAM_PACKAGE_TYPE_STRUCT;

typedef union {
  struct {
    UINT8  MaximumActivateCount                :  4; ///< Bits 3:0
    UINT8  MaximumActivateWindow               :  2; ///< Bits 5:4
    UINT8  Reserved                            :  2; ///< Bits 7:6
  } Bits;
  UINT8  Data;
} SPD4_SDRAM_OPTIONAL_FEATURES_STRUCT;

typedef union {
  struct {
    UINT8  Reserved                            :  8; ///< Bits 7:0
  } Bits;
  UINT8  Data;
} SPD4_SDRAM_THERMAL_REFRESH_STRUCT;

typedef union {
  struct {
    UINT8  Reserved                            :  5; ///< Bits 4:0
    UINT8  SoftPPR                             :  1; ///< Bits 5:5
    UINT8  PostPackageRepair                   :  2; ///< Bits 7:6
  } Bits;
  UINT8  Data;
} SPD4_OTHER_SDRAM_OPTIONAL_FEATURES_STRUCT;

typedef union {
  struct {
    UINT8  SignalLoading                       :  2; ///< Bits 1:0
    UINT8  DRAMDensityRatio                    :  2; ///< Bits 3:2
    UINT8  DieCount                            :  3; ///< Bits 6:4
    UINT8  SdramPackageType                    :  1; ///< Bits 7:7
  } Bits;
  UINT8  Data;
} SPD4_SECONDARY_SDRAM_PACKAGE_TYPE_STRUCT;

typedef union {
  struct {
    UINT8  OperationAt1_20                     :  1; ///< Bits 0:0
    UINT8  EndurantAt1_20                      :  1; ///< Bits 1:1
    UINT8  Reserved                            :  6; ///< Bits 7:2
  } Bits;
  UINT8  Data;
} SPD4_MODULE_NOMINAL_VOLTAGE_STRUCT;

typedef union {
  struct {
    UINT8  SdramDeviceWidth                    :  3; ///< Bits 2:0
    UINT8  RankCount                           :  3; ///< Bits 5:3
    UINT8  RankMix                             :  1; ///< Bits 6:6
    UINT8  Reserved                            :  1; ///< Bits 7:7
  } Bits;
  UINT8  Data;
} SPD4_MODULE_ORGANIZATION_STRUCT;

typedef union {
  struct {
    UINT8  PrimaryBusWidth                     :  3; ///< Bits 2:0
    UINT8  BusWidthExtension                   :  2; ///< Bits 4:3
    UINT8  Reserved                            :  3; ///< Bits 7:5
  } Bits;
  UINT8  Data;
} SPD4_MODULE_MEMORY_BUS_WIDTH_STRUCT;

typedef union {
  struct {
    UINT8  Reserved                            :  7; ///< Bits 6:0
    UINT8  ThermalSensorPresence               :  1; ///< Bits 7:7
  } Bits;
  UINT8  Data;
} SPD4_MODULE_THERMAL_SENSOR_STRUCT;

typedef union {
  struct {
    UINT8  ExtendedBaseModuleType              :  4; ///< Bits 3:0
    UINT8  Reserved                            :  4; ///< Bits 7:4
  } Bits;
  UINT8  Data;
} SPD4_EXTENDED_MODULE_TYPE_STRUCT;

typedef union {
  struct {
    UINT8  Fine                                :  2; ///< Bits 1:0
    UINT8  Medium                              :  2; ///< Bits 3:2
    UINT8  Reserved                            :  4; ///< Bits 7:4
  } Bits;
  UINT8  Data;
} SPD4_TIMEBASE_STRUCT;

typedef union {
  struct {
    UINT8  tCKmin                              :  8; ///< Bits 7:0
  } Bits;
  UINT8  Data;
} SPD4_TCK_MIN_MTB_STRUCT;

typedef union {
  struct {
    UINT8  tCKmax                              :  8; ///< Bits 7:0
  } Bits;
  UINT8  Data;
} SPD4_TCK_MAX_MTB_STRUCT;

typedef union {
  struct {
    UINT32 Cl7                                 :  1; ///< Bits 0:0
    UINT32 Cl8                                 :  1; ///< Bits 1:1
    UINT32 Cl9                                 :  1; ///< Bits 2:2
    UINT32 Cl10                                :  1; ///< Bits 3:3
    UINT32 Cl11                                :  1; ///< Bits 4:4
    UINT32 Cl12                                :  1; ///< Bits 5:5
    UINT32 Cl13                                :  1; ///< Bits 6:6
    UINT32 Cl14                                :  1; ///< Bits 7:7
    UINT32 Cl15                                :  1; ///< Bits 8:8
    UINT32 Cl16                                :  1; ///< Bits 9:9
    UINT32 Cl17                                :  1; ///< Bits 10:10
    UINT32 Cl18                                :  1; ///< Bits 11:11
    UINT32 Cl19                                :  1; ///< Bits 12:12
    UINT32 Cl20                                :  1; ///< Bits 13:13
    UINT32 Cl21                                :  1; ///< Bits 14:14
    UINT32 Cl22                                :  1; ///< Bits 15:15
    UINT32 Cl23                                :  1; ///< Bits 16:16
    UINT32 Cl24                                :  1; ///< Bits 17:17
    UINT32 Cl25                                :  1; ///< Bits 18:18
    UINT32 Cl26                                :  1; ///< Bits 19:19
    UINT32 Cl27                                :  1; ///< Bits 20:20
    UINT32 Cl28                                :  1; ///< Bits 21:21
    UINT32 Cl29                                :  1; ///< Bits 22:22
    UINT32 Cl30                                :  1; ///< Bits 23:23
    UINT32 Cl31                                :  1; ///< Bits 24:24
    UINT32 Cl32                                :  1; ///< Bits 25:25
    UINT32 Cl33                                :  1; ///< Bits 26:26
    UINT32 Cl34                                :  1; ///< Bits 27:27
    UINT32 Cl35                                :  1; ///< Bits 28:28
    UINT32 Cl36                                :  1; ///< Bits 29:29
    UINT32 Reserved                            :  1; ///< Bits 30:30
    UINT32 ClRange                             :  1; ///< Bits 31:31
  } Bits;
  struct {
    UINT32 Cl23                                :  1; ///< Bits 0:0
    UINT32 Cl24                                :  1; ///< Bits 1:1
    UINT32 Cl25                                :  1; ///< Bits 2:2
    UINT32 Cl26                                :  1; ///< Bits 3:3
    UINT32 Cl27                                :  1; ///< Bits 4:4
    UINT32 Cl28                                :  1; ///< Bits 5:5
    UINT32 Cl29                                :  1; ///< Bits 6:6
    UINT32 Cl30                                :  1; ///< Bits 7:7
    UINT32 Cl31                                :  1; ///< Bits 8:8
    UINT32 Cl32                                :  1; ///< Bits 9:9
    UINT32 Cl33                                :  1; ///< Bits 10:10
    UINT32 Cl34                                :  1; ///< Bits 11:11
    UINT32 Cl35                                :  1; ///< Bits 12:12
    UINT32 Cl36                                :  1; ///< Bits 13:13
    UINT32 Cl37                                :  1; ///< Bits 14:14
    UINT32 Cl38                                :  1; ///< Bits 15:15
    UINT32 Cl39                                :  1; ///< Bits 16:16
    UINT32 Cl40                                :  1; ///< Bits 17:17
    UINT32 Cl41                                :  1; ///< Bits 18:18
    UINT32 Cl42                                :  1; ///< Bits 19:19
    UINT32 Cl43                                :  1; ///< Bits 20:20
    UINT32 Cl44                                :  1; ///< Bits 21:21
    UINT32 Cl45                                :  1; ///< Bits 22:22
    UINT32 Cl46                                :  1; ///< Bits 23:23
    UINT32 Cl47                                :  1; ///< Bits 24:24
    UINT32 Cl48                                :  1; ///< Bits 25:25
    UINT32 Cl49                                :  1; ///< Bits 26:26
    UINT32 Cl50                                :  1; ///< Bits 27:27
    UINT32 Cl51                                :  1; ///< Bits 28:28
    UINT32 Cl52                                :  1; ///< Bits 29:29
    UINT32 Reserved                            :  1; ///< Bits 30:30
    UINT32 ClRange                             :  1; ///< Bits 31:31
  } HighRangeBits;
  UINT32 Data;
  UINT16 Data16[2];
  UINT8  Data8[4];
} SPD4_CAS_LATENCIES_SUPPORTED_STRUCT;

typedef union {
  struct {
    UINT8  tAAmin                              :  8; ///< Bits 7:0
  } Bits;
  UINT8  Data;
} SPD4_TAA_MIN_MTB_STRUCT;

typedef union {
  struct {
    UINT8  tRCDmin                             :  8; ///< Bits 7:0
  } Bits;
  UINT8  Data;
} SPD4_TRCD_MIN_MTB_STRUCT;

typedef union {
  struct {
    UINT8  tRPmin                              :  8; ///< Bits 7:0
  } Bits;
  UINT8  Data;
} SPD4_TRP_MIN_MTB_STRUCT;

typedef union {
  struct {
    UINT8  tRASminUpper                        :  4; ///< Bits 3:0
    UINT8  tRCminUpper                         :  4; ///< Bits 7:4
  } Bits;
  UINT8  Data;
} SPD4_TRAS_TRC_MIN_MTB_STRUCT;

typedef union {
  struct {
    UINT8  tRASmin                             :  8; ///< Bits 7:0
  } Bits;
  UINT8  Data;
} SPD4_TRAS_MIN_MTB_STRUCT;

typedef union {
  struct {
    UINT8  tRCmin                              :  8; ///< Bits 7:0
  } Bits;
  UINT8  Data;
} SPD4_TRC_MIN_MTB_STRUCT;

typedef union {
  struct {
    UINT16 tRFCmin                             :  16; ///< Bits 15:0
  } Bits;
  UINT16 Data;
  UINT8  Data8[2];
} SPD4_TRFC_MIN_MTB_STRUCT;

typedef union {
  struct {
    UINT8  tFAWminUpper                        :  4; ///< Bits 3:0
    UINT8  Reserved                            :  4; ///< Bits 7:4
  } Bits;
  UINT8  Data;
} SPD4_TFAW_MIN_MTB_UPPER_STRUCT;

typedef union {
  struct {
    UINT8  tFAWmin                             :  8; ///< Bits 7:0
  } Bits;
  UINT8  Data;
} SPD4_TFAW_MIN_MTB_STRUCT;

typedef union {
  struct {
    UINT8  tRRDmin                             :  8; ///< Bits 7:0
  } Bits;
  UINT8  Data;
} SPD4_TRRD_MIN_MTB_STRUCT;

typedef union {
  struct {
    UINT8  tCCDmin                             :  8; ///< Bits 7:0
  } Bits;
  UINT8  Data;
} SPD4_TCCD_MIN_MTB_STRUCT;

typedef union {
  struct {
    UINT8  tWRminMostSignificantNibble         :  4; ///< Bits 3:0
    UINT8  Reserved                            :  4; ///< Bits 7:4
  } Bits;
  UINT8  Data;
} SPD4_TWR_UPPER_NIBBLE_STRUCT;

typedef union {
  struct {
    UINT8  tWRmin                              :  8; ///< Bits 7:0
  } Bits;
  UINT8  Data;
} SPD4_TWR_MIN_MTB_STRUCT;

typedef union {
  struct {
    UINT8  tWTR_SminMostSignificantNibble      :  4; ///< Bits 3:0
    UINT8  tWTR_LminMostSignificantNibble      :  4; ///< Bits 7:4
  } Bits;
  UINT8  Data;
} SPD4_TWTR_UPPER_NIBBLE_STRUCT;

typedef union {
  struct {
    UINT8  tWTRmin                             :  8; ///< Bits 7:0
  } Bits;
  UINT8  Data;
} SPD4_TWTR_MIN_MTB_STRUCT;

typedef union {
  struct {
    UINT8  BitOrderatSDRAM                     :  5; ///< Bits 4:0
    UINT8  WiredtoUpperLowerNibble             :  1; ///< Bits 5:5
    UINT8  PackageRankMap                      :  2; ///< Bits 7:6
  } Bits;
  UINT8  Data;
} SPD4_CONNECTOR_BIT_MAPPING_BYTE_STRUCT;

typedef union {
  struct {
    INT8  tCCDminFine                          :  8; ///< Bits 7:0
  } Bits;
  INT8  Data;
} SPD4_TCCD_MIN_FTB_STRUCT;

typedef union {
  struct {
    INT8  tRRDminFine                          :  8; ///< Bits 7:0
  } Bits;
  INT8  Data;
} SPD4_TRRD_MIN_FTB_STRUCT;

typedef union {
  struct {
    INT8  tRCminFine                           :  8; ///< Bits 7:0
  } Bits;
  INT8  Data;
} SPD4_TRC_MIN_FTB_STRUCT;

typedef union {
  struct {
    INT8  tRPminFine                           :  8; ///< Bits 7:0
  } Bits;
  INT8  Data;
} SPD4_TRP_MIN_FTB_STRUCT;

typedef union {
  struct {
    INT8  tRCDminFine                          :  8; ///< Bits 7:0
  } Bits;
  INT8  Data;
} SPD4_TRCD_MIN_FTB_STRUCT;

typedef union {
  struct {
    INT8  tAAminFine                           :  8; ///< Bits 7:0
  } Bits;
  INT8  Data;
} SPD4_TAA_MIN_FTB_STRUCT;

typedef union {
  struct {
    INT8  tCKmaxFine                           :  8; ///< Bits 7:0
  } Bits;
  INT8  Data;
} SPD4_TCK_MAX_FTB_STRUCT;

typedef union {
  struct {
    INT8  tCKminFine                           :  8; ///< Bits 7:0
  } Bits;
  INT8  Data;
} SPD4_TCK_MIN_FTB_STRUCT;

typedef union {
  struct {
    UINT8  Height                              :  5; ///< Bits 4:0
    UINT8  RawCardExtension                    :  3; ///< Bits 7:5
  } Bits;
  UINT8  Data;
} SPD4_UNBUF_MODULE_NOMINAL_HEIGHT;

typedef union {
  struct {
    UINT8  FrontThickness                      :  4; ///< Bits 3:0
    UINT8  BackThickness                       :  4; ///< Bits 7:4
  } Bits;
  UINT8  Data;
} SPD4_UNBUF_MODULE_NOMINAL_THICKNESS;

typedef union {
  struct {
    UINT8  Card                                :  5; ///< Bits 4:0
    UINT8  Revision                            :  2; ///< Bits 6:5
    UINT8  Extension                           :  1; ///< Bits 7:7
  } Bits;
  UINT8  Data;
} SPD4_UNBUF_REFERENCE_RAW_CARD;

typedef union {
  struct {
    UINT8  MappingRank1                        :  1; ///< Bits 0:0
    UINT8  Reserved                            :  7; ///< Bits 7:1
  } Bits;
  UINT8  Data;
} SPD4_UNBUF_ADDRESS_MAPPING;

typedef union {
  struct {
    UINT8  Height                              :  5; ///< Bits 4:0
    UINT8  Reserved                            :  3; ///< Bits 7:5
  } Bits;
  UINT8  Data;
} SPD4_RDIMM_MODULE_NOMINAL_HEIGHT;

typedef union {
  struct {
    UINT8  FrontThickness                      :  4; ///< Bits 3:0
    UINT8  BackThickness                       :  4; ///< Bits 7:4
  } Bits;
  UINT8  Data;
} SPD4_RDIMM_MODULE_NOMINAL_THICKNESS;

typedef union {
  struct {
    UINT8  Card                                :  5; ///< Bits 4:0
    UINT8  Revision                            :  2; ///< Bits 6:5
    UINT8  Extension                           :  1; ///< Bits 7:7
  } Bits;
  UINT8  Data;
} SPD4_RDIMM_REFERENCE_RAW_CARD;

typedef union {
  struct {
    UINT8  RegisterCount                       :  2; ///< Bits 1:0
    UINT8  DramRowCount                        :  2; ///< Bits 3:2
    UINT8  RegisterType                        :  4; ///< Bits 7:4
  } Bits;
  UINT8  Data;
} SPD4_RDIMM_MODULE_ATTRIBUTES;

typedef union {
  struct {
    UINT8  HeatSpreaderThermalCharacteristics  :  7; ///< Bits 6:0
    UINT8  HeatSpreaderSolution                :  1; ///< Bits 7:7
  } Bits;
  UINT8  Data;
} SPD4_RDIMM_THERMAL_HEAT_SPREADER_SOLUTION;

typedef union {
  struct {
    UINT16 ContinuationCount                   :  7; ///< Bits 6:0
    UINT16 ContinuationParity                  :  1; ///< Bits 7:7
    UINT16 LastNonZeroByte                     :  8; ///< Bits 15:8
  } Bits;
  UINT16 Data;
  UINT8  Data8[2];
} SPD4_MANUFACTURER_ID_CODE;

typedef union {
  struct {
    UINT8  RegisterRevisionNumber;             ///< Bits 7:0
  } Bits;
  UINT8  Data;
} SPD4_RDIMM_REGISTER_REVISION_NUMBER;

typedef union {
  struct {
    UINT8 Rank1Mapping                        :  1; ///< Bits 0:0
    UINT8 Reserved                            :  7; ///< Bits 7:1
  } Bits;
  UINT8  Data;
} SPD4_RDIMM_ADDRESS_MAPPING_FROM_REGISTER_TO_DRAM;

typedef union {
  struct {
    UINT8 Cke                                 :  2; ///< Bits 1:0
    UINT8 Odt                                 :  2; ///< Bits 3:2
    UINT8 CommandAddress                      :  2; ///< Bits 5:4
    UINT8 ChipSelect                          :  2; ///< Bits 7:6
  } Bits;
  UINT8  Data;
} SPD4_RDIMM_REGISTER_OUTPUT_DRIVE_STRENGTH_FOR_CONTROL_COMMAND_ADDRESS;

typedef union {
  struct {
    UINT8 Y0Y2                                :  2; ///< Bits 1:0
    UINT8 Y1Y3                                :  2; ///< Bits 3:2
    UINT8 Reserved0                           :  2; ///< Bits 5:4
    UINT8 RcdOutputSlewRateControl            :  1; ///< Bits 6:6
    UINT8 Reserved1                           :  1; ///< Bits 7:7
  } Bits;
  UINT8  Data;
} SPD4_RDIMM_REGISTER_OUTPUT_DRIVE_STRENGTH_FOR_CLOCK;

typedef union {
  struct {
    UINT8  Height                             :  5; ///< Bits 4:0
    UINT8  Reserved                           :  3; ///< Bits 7:5
  } Bits;
  UINT8  Data;
} SPD4_LRDIMM_MODULE_NOMINAL_HEIGHT;

typedef union {
  struct {
    UINT8  FrontThickness                     :  4; ///< Bits 3:0
    UINT8  BackThickness                      :  4; ///< Bits 7:4
  } Bits;
  UINT8  Data;
} SPD4_LRDIMM_MODULE_NOMINAL_THICKNESS;

typedef union {
  struct {
    UINT8  Card                               :  5; ///< Bits 4:0
    UINT8  Revision                           :  2; ///< Bits 6:5
    UINT8  Extension                          :  1; ///< Bits 7:7
  } Bits;
  UINT8  Data;
} SPD4_LRDIMM_REFERENCE_RAW_CARD;

typedef union {
  struct {
    UINT8  RegisterCount                      :  2; ///< Bits 1:0
    UINT8  DramRowCount                       :  2; ///< Bits 3:2
    UINT8  RegisterType                       :  4; ///< Bits 7:4
  } Bits;
  UINT8  Data;
} SPD4_LRDIMM_MODULE_ATTRIBUTES;

typedef union {
  struct {
    UINT8  HeatSpreaderThermalCharacteristics :  7; ///< Bits 6:0
    UINT8  HeatSpreaderSolution               :  1; ///< Bits 7:7
  } Bits;
  UINT8  Data;
} SPD4_LRDIMM_THERMAL_HEAT_SPREADER_SOLUTION;

typedef union {
  struct {
    UINT8  RegisterRevisionNumber;                  ///< Bits 7:0
  } Bits;
  UINT8  Data;
} SPD4_LRDIMM_REGISTER_REVISION_NUMBER;

typedef union {
  struct {
    UINT8 Rank1Mapping                        :  1; ///< Bits 0:0
    UINT8 Reserved                            :  7; ///< Bits 7:1
  } Bits;
  UINT8  Data;
} SPD4_LRDIMM_ADDRESS_MAPPING_FROM_REGISTER_TO_DRAM;

typedef union {
  struct {
    UINT8 Cke                                 :  2; ///< Bits 1:0
    UINT8 Odt                                 :  2; ///< Bits 3:2
    UINT8 CommandAddress                      :  2; ///< Bits 5:4
    UINT8 ChipSelect                          :  2; ///< Bits 7:6
  } Bits;
  UINT8  Data;
} SPD4_LRDIMM_REGISTER_OUTPUT_DRIVE_STRENGTH_FOR_CONTROL_COMMAND_ADDRESS;

typedef union {
  struct {
    UINT8 Y0Y2                                :  2; ///< Bits 1:0
    UINT8 Y1Y3                                :  2; ///< Bits 3:2
    UINT8 Reserved0                           :  2; ///< Bits 5:4
    UINT8 RcdOutputSlewRateControl            :  1; ///< Bits 6:6
    UINT8 Reserved1                           :  1; ///< Bits 7:7
  } Bits;
  UINT8  Data;
} SPD4_LRDIMM_REGISTER_OUTPUT_DRIVE_STRENGTH_FOR_CLOCK;

typedef struct {
  UINT8  DataBufferRevisionNumber;
} SPD4_LRDIMM_DATA_BUFFER_REVISION_NUMBER;

typedef union {
  struct {
    UINT8  DramVrefDQForPackageRank0          :  6; ///< Bits 5:0
    UINT8  Reserved                           :  2; ///< Bits 7:6
  } Bits;
  UINT8  Data;
} SPD4_LRDIMM_DRAM_VREFDQ_FOR_PACKAGE_RANK;

typedef struct {
  UINT8  DataBufferVrefDQforDramInterface;
} SPD4_LRDIMM_DATA_BUFFER_VREFDQ_FOR_DRAM_INTERFACE;

typedef union {
  struct {
    UINT8  DramInterfaceMdqDriveStrength           :  4; ///< Bits 3:0
    UINT8  DramInterfaceMdqReadTerminationStrength :  4; ///< Bits 7:4
  } Bits;
  UINT8  Data;
} SPD4_LRDIMM_DATA_BUFFER_MDQ_DRIVE_STRENGTH_RTT_FOR_DATA_RATE;

typedef union {
  struct {
    UINT8  DataRateLe1866                           :  2; ///< Bits 1:0
    UINT8  DataRateLe2400                           :  2; ///< Bits 3:2
    UINT8  DataRateLe3200                           :  2; ///< Bits 5:4
    UINT8  Reserved                                 :  2; ///< Bits 7:6
  } Bits;
  UINT8  Data;
} SPD4_LRDIMM_DRAM_DRIVE_STRENGTH;

typedef union {
  struct {
    UINT8  Rtt_Nom                                  :  3; ///< Bits 2:0
    UINT8  Rtt_WR                                   :  3; ///< Bits 5:3
    UINT8  Reserved                                 :  2; ///< Bits 7:6
  } Bits;
  UINT8  Data;
} SPD4_LRDIMM_DRAM_ODT_RTT_WR_RTT_NOM_FOR_DATA_RATE;

typedef union {
  struct {
    UINT8  PackageRanks0_1                          :  3; ///< Bits 2:0
    UINT8  PackageRanks2_3                          :  3; ///< Bits 5:3
    UINT8  Reserved                                 :  2; ///< Bits 7:6
  } Bits;
  UINT8  Data;
} SPD4_LRDIMM_DRAM_ODT_RTT_PARK_FOR_DATA_RATE;

typedef union {
  struct {
    UINT8  Rank0                                    :  1; ///< Bits 0:0
    UINT8  Rank1                                    :  1; ///< Bits 1:1
    UINT8  Rank2                                    :  1; ///< Bits 2:2
    UINT8  Rank3                                    :  1; ///< Bits 3:3
    UINT8  DataBuffer                               :  1; ///< Bits 4:4
    UINT8  Reserved                                 :  3; ///< Bits 7:5
  } Bits;
  UINT8  Data;
} SPD4_LRDIMM_DATA_BUFFER_VREFDQ_FOR_DRAM_INTERFACE_RANGE;

typedef union {
  struct {
    UINT8  DataBufferGainAdjustment                 :  1; ///< Bits 0:0
    UINT8  DataBufferDfe                            :  1; ///< Bits 1:1
    UINT8  Reserved                                 :  6; ///< Bits 7:2
  } Bits;
  UINT8  Data;
} SPD4_LRDIMM_DATA_BUFFER_DQ_DECISION_FEEDBACK_EQUALIZATION;

typedef UINT16 SPD4_NVDIMM_MODULE_PRODUCT_IDENTIFIER;

typedef union {
  struct {
    UINT16 ContinuationCount                   :  7; ///< Bits 6:0
    UINT16 ContinuationParity                  :  1; ///< Bits 7:7
    UINT16 LastNonZeroByte                     :  8; ///< Bits 15:8
  } Bits;
  UINT16 Data;
  UINT8  Data8[2];
} SPD4_NVDIMM_SUBSYSTEM_CONTROLLER_MANUFACTURER_ID_CODE;

typedef UINT16 SPD4_NVDIMM_SUBSYSTEM_CONTROLLER_IDENTIFIER;

typedef UINT8 SPD4_NVDIMM_SUBSYSTEM_CONTROLLER_REVISION_CODE;

typedef union {
  struct {
    UINT8  Card                                :  5; ///< Bits 4:0
    UINT8  Revision                            :  2; ///< Bits 6:5
    UINT8  Extension                           :  1; ///< Bits 7:7
  } Bits;
  UINT8  Data;
} SPD4_NVDIMM_REFERENCE_RAW_CARD;

typedef union {
  struct {
    UINT8  Reserved                            :  4; ///< Bits 3:0
    UINT8  Extension                           :  4; ///< Bits 7:4
  } Bits;
  UINT8  Data;
} SPD4_NVDIMM_MODULE_CHARACTERISTICS;

typedef struct {
  UINT8  Reserved;
  UINT8  MediaType;
} SPD4_NVDIMM_HYBRID_MODULE_MEDIA_TYPES;

typedef UINT8 SPD4_NVDIMM_MAXIMUM_NONVOLATILE_MEMORY_INITIALIZATION_TIME;

typedef union {
  struct {
    UINT16 FunctionInterface                   :  5; ///< Bits 4:0
    UINT16 FunctionClass                       :  5; ///< Bits 9:5
    UINT16 BlockOffset                         :  4; ///< Bits 13:10
    UINT16 Reserved                            :  1; ///< Bits 14:14
    UINT16 Implemented                         :  1; ///< Bits 15:15
  } Bits;
  UINT16 Data;
  UINT8  Data8[2];
} SPD4_NVDIMM_FUNCTION_INTERFACE_DESCRIPTOR;

typedef struct {
  UINT8  Year;                                 ///< Year represented in BCD (00h = 2000)
  UINT8  Week;                                 ///< Year represented in BCD (47h = week 47)
} SPD4_MANUFACTURING_DATE;

typedef union {
  UINT32 Data;
  UINT16 SerialNumber16[2];
  UINT8  SerialNumber8[4];
} SPD4_MANUFACTURER_SERIAL_NUMBER;

typedef struct {
  UINT8 Location;                              ///< Module Manufacturing Location
} SPD4_MANUFACTURING_LOCATION;

typedef struct {
  SPD4_MANUFACTURER_ID_CODE            IdCode;                   ///< Module Manufacturer ID Code
  SPD4_MANUFACTURING_LOCATION          Location;                 ///< Module Manufacturing Location
  SPD4_MANUFACTURING_DATE              Date;                     ///< Module Manufacturing Year, in BCD (range: 2000-2255)
  SPD4_MANUFACTURER_SERIAL_NUMBER      SerialNumber;             ///< Module Serial Number
} SPD4_UNIQUE_MODULE_ID;

typedef union {
  UINT16 Crc[1];
  UINT8  Data8[2];
} SPD4_CYCLIC_REDUNDANCY_CODE;

typedef struct {
  SPD4_DEVICE_DESCRIPTION_STRUCT            Description;              ///< 0       Number of Serial PD Bytes Written / SPD Device Size / CRC Coverage 1, 2
  SPD4_REVISION_STRUCT                      Revision;                 ///< 1       SPD Revision
  SPD4_DRAM_DEVICE_TYPE_STRUCT              DramDeviceType;           ///< 2       DRAM Device Type
  SPD4_MODULE_TYPE_STRUCT                   ModuleType;               ///< 3       Module Type
  SPD4_SDRAM_DENSITY_BANKS_STRUCT           SdramDensityAndBanks;     ///< 4       SDRAM Density and Banks
  SPD4_SDRAM_ADDRESSING_STRUCT              SdramAddressing;          ///< 5       SDRAM Addressing
  SPD4_PRIMARY_SDRAM_PACKAGE_TYPE_STRUCT    PrimarySdramPackageType;  ///< 6       Primary SDRAM Package Type
  SPD4_SDRAM_OPTIONAL_FEATURES_STRUCT       SdramOptionalFeatures;    ///< 7       SDRAM Optional Features
  SPD4_SDRAM_THERMAL_REFRESH_STRUCT         ThermalAndRefreshOptions; ///< 8       SDRAM Thermal and Refresh Options
  SPD4_OTHER_SDRAM_OPTIONAL_FEATURES_STRUCT OtherOptionalFeatures;    ///< 9       Other SDRAM Optional Features
  SPD4_SECONDARY_SDRAM_PACKAGE_TYPE_STRUCT  SecondarySdramPackageType;///< 10      Secondary SDRAM Package Type
  SPD4_MODULE_NOMINAL_VOLTAGE_STRUCT        ModuleNominalVoltage;     ///< 11      Module Nominal Voltage, VDD
  SPD4_MODULE_ORGANIZATION_STRUCT           ModuleOrganization;       ///< 12      Module Organization
  SPD4_MODULE_MEMORY_BUS_WIDTH_STRUCT       ModuleMemoryBusWidth;     ///< 13      Module Memory Bus Width
  SPD4_MODULE_THERMAL_SENSOR_STRUCT         ModuleThermalSensor;      ///< 14      Module Thermal Sensor
  SPD4_EXTENDED_MODULE_TYPE_STRUCT          ExtendedModuleType;       ///< 15      Extended Module Type
  UINT8                                     Reserved0;                ///< 16      Reserved
  SPD4_TIMEBASE_STRUCT                      Timebase;                 ///< 17      Timebases
  SPD4_TCK_MIN_MTB_STRUCT                   tCKmin;                   ///< 18      SDRAM Minimum Cycle Time (tCKmin)
  SPD4_TCK_MAX_MTB_STRUCT                   tCKmax;                   ///< 19      SDRAM Maximum Cycle Time (tCKmax)
  SPD4_CAS_LATENCIES_SUPPORTED_STRUCT       CasLatencies;             ///< 20-23   CAS Latencies Supported
  SPD4_TAA_MIN_MTB_STRUCT                   tAAmin;                   ///< 24      Minimum CAS Latency Time (tAAmin)
  SPD4_TRCD_MIN_MTB_STRUCT                  tRCDmin;                  ///< 25      Minimum RAS# to CAS# Delay Time (tRCDmin)
  SPD4_TRP_MIN_MTB_STRUCT                   tRPmin;                   ///< 26      Minimum Row Precharge Delay Time (tRPmin)
  SPD4_TRAS_TRC_MIN_MTB_STRUCT              tRASMintRCMinUpper;       ///< 27      Upper Nibbles for tRAS and tRC
  SPD4_TRAS_MIN_MTB_STRUCT                  tRASmin;                  ///< 28      Minimum Active to Precharge Delay Time (tRASmin), Least Significant Byte
  SPD4_TRC_MIN_MTB_STRUCT                   tRCmin;                   ///< 29      Minimum Active to Active/Refresh Delay Time (tRCmin), Least Significant Byte
  SPD4_TRFC_MIN_MTB_STRUCT                  tRFC1min;                 ///< 30-31   Minimum Refresh Recovery Delay Time (tRFC1min)
  SPD4_TRFC_MIN_MTB_STRUCT                  tRFC2min;                 ///< 32-33   Minimum Refresh Recovery Delay Time (tRFC2min)
  SPD4_TRFC_MIN_MTB_STRUCT                  tRFC4min;                 ///< 34-35   Minimum Refresh Recovery Delay Time (tRFC4min)
  SPD4_TFAW_MIN_MTB_UPPER_STRUCT            tFAWMinUpper;             ///< 36      Upper Nibble for tFAW
  SPD4_TFAW_MIN_MTB_STRUCT                  tFAWmin;                  ///< 37      Minimum Four Activate Window Delay Time (tFAWmin)
  SPD4_TRRD_MIN_MTB_STRUCT                  tRRD_Smin;                ///< 38      Minimum Activate to Activate Delay Time (tRRD_Smin), different bank group
  SPD4_TRRD_MIN_MTB_STRUCT                  tRRD_Lmin;                ///< 39      Minimum Activate to Activate Delay Time (tRRD_Lmin), same bank group
  SPD4_TCCD_MIN_MTB_STRUCT                  tCCD_Lmin;                ///< 40      Minimum CAS to CAS Delay Time (tCCD_Lmin), Same Bank Group
  SPD4_TWR_UPPER_NIBBLE_STRUCT              tWRUpperNibble;           ///< 41      Upper Nibble for tWRmin
  SPD4_TWR_MIN_MTB_STRUCT                   tWRmin;                   ///< 42      Minimum Write Recovery Time (tWRmin)
  SPD4_TWTR_UPPER_NIBBLE_STRUCT             tWTRUpperNibble;          ///< 43      Upper Nibbles for tWTRmin
  SPD4_TWTR_MIN_MTB_STRUCT                  tWTR_Smin;                ///< 44      Minimum Write to Read Time (tWTR_Smin), Different Bank Group
  SPD4_TWTR_MIN_MTB_STRUCT                  tWTR_Lmin;                ///< 45      Minimum Write to Read Time (tWTR_Lmin), Same Bank Group
  UINT8                                     Reserved1[59 - 46 + 1];   ///< 46-59   Reserved
  SPD4_CONNECTOR_BIT_MAPPING_BYTE_STRUCT    BitMapping[77 - 60 + 1];  ///< 60-77   Connector to SDRAM Bit Mapping
  UINT8                                     Reserved2[116 - 78 + 1];  ///< 78-116  Reserved
  SPD4_TCCD_MIN_FTB_STRUCT                  tCCD_LminFine;            ///< 117     Fine Offset for Minimum CAS to CAS Delay Time (tCCD_Lmin), same bank group
  SPD4_TRRD_MIN_FTB_STRUCT                  tRRD_LminFine;            ///< 118     Fine Offset for Minimum Activate to Activate Delay Time (tRRD_Lmin), different bank group
  SPD4_TRRD_MIN_FTB_STRUCT                  tRRD_SminFine;            ///< 119     Fine Offset for Minimum Activate to Activate Delay Time (tRRD_Smin), same bank group
  SPD4_TRC_MIN_FTB_STRUCT                   tRCminFine;               ///< 120     Fine Offset for Minimum Active to Active/Refresh Delay Time (tRCmin)
  SPD4_TRP_MIN_FTB_STRUCT                   tRPminFine;               ///< 121     Fine Offset for Minimum Row Precharge Delay Time (tRPabmin)
  SPD4_TRCD_MIN_FTB_STRUCT                  tRCDminFine;              ///< 122     Fine Offset for Minimum RAS# to CAS# Delay Time (tRCDmin)
  SPD4_TAA_MIN_FTB_STRUCT                   tAAminFine;               ///< 123     Fine Offset for Minimum CAS Latency Time (tAAmin)
  SPD4_TCK_MAX_FTB_STRUCT                   tCKmaxFine;               ///< 124     Fine Offset for SDRAM Minimum Cycle Time (tCKmax)
  SPD4_TCK_MIN_FTB_STRUCT                   tCKminFine;               ///< 125     Fine Offset for SDRAM Maximum Cycle Time (tCKmin)
  SPD4_CYCLIC_REDUNDANCY_CODE               Crc;                      ///< 126-127 Cyclical Redundancy Code (CRC)
} SPD4_BASE_SECTION;

typedef struct {
  SPD4_UNBUF_MODULE_NOMINAL_HEIGHT     ModuleNominalHeight;      ///< 128     Module Nominal Height
  SPD4_UNBUF_MODULE_NOMINAL_THICKNESS  ModuleMaximumThickness;   ///< 129     Module Maximum Thickness
  SPD4_UNBUF_REFERENCE_RAW_CARD        ReferenceRawCardUsed;     ///< 130     Reference Raw Card Used
  SPD4_UNBUF_ADDRESS_MAPPING           AddressMappingEdgeConn;   ///< 131     Address Mapping from Edge Connector to DRAM
  UINT8                                Reserved[253 - 132 + 1];  ///< 132-253 Reserved
  SPD4_CYCLIC_REDUNDANCY_CODE          Crc;                      ///< 254-255 Cyclical Redundancy Code (CRC)
} SPD4_MODULE_UNBUFFERED;

typedef struct {
  SPD4_RDIMM_MODULE_NOMINAL_HEIGHT     ModuleNominalHeight;      ///< 128     Module Nominal Height
  SPD4_RDIMM_MODULE_NOMINAL_THICKNESS  ModuleMaximumThickness;   ///< 129     Module Maximum Thickness
  SPD4_RDIMM_REFERENCE_RAW_CARD        ReferenceRawCardUsed;     ///< 130     Reference Raw Card Used
  SPD4_RDIMM_MODULE_ATTRIBUTES         DimmModuleAttributes;     ///< 131     DIMM Module Attributes
  SPD4_RDIMM_THERMAL_HEAT_SPREADER_SOLUTION                             DimmThermalHeatSpreaderSolution;     ///< 132     RDIMM Thermal Heat Spreader Solution
  SPD4_MANUFACTURER_ID_CODE                                             RegisterManufacturerIdCode;          ///< 133-134 Register Manufacturer ID Code
  SPD4_RDIMM_REGISTER_REVISION_NUMBER                                   RegisterRevisionNumber;              ///< 135     Register Revision Number
  SPD4_RDIMM_ADDRESS_MAPPING_FROM_REGISTER_TO_DRAM                      AddressMappingFromRegisterToDRAM;    ///< 136     Address Mapping from Register to DRAM
  SPD4_RDIMM_REGISTER_OUTPUT_DRIVE_STRENGTH_FOR_CONTROL_COMMAND_ADDRESS RegisterOutputDriveStrengthForControlCommandAddress; ///< 137 Register Output Drive Strength for Control and Command Address
  SPD4_RDIMM_REGISTER_OUTPUT_DRIVE_STRENGTH_FOR_CLOCK                   RegisterOutputDriveStrengthForClock; ///< 138     Register Output Drive Strength for Clock
  UINT8                                                                 Reserved[253 - 139 + 1];             ///< 253-139 Reserved
  SPD4_CYCLIC_REDUNDANCY_CODE                                           Crc;                                 ///< 254-255 Cyclical Redundancy Code (CRC)
} SPD4_MODULE_REGISTERED;

typedef struct {
  SPD4_LRDIMM_MODULE_NOMINAL_HEIGHT           ModuleNominalHeight;         ///< 128     Module Nominal Height
  SPD4_LRDIMM_MODULE_NOMINAL_THICKNESS        ModuleMaximumThickness;      ///< 129     Module Maximum Thickness
  SPD4_LRDIMM_REFERENCE_RAW_CARD              ReferenceRawCardUsed;        ///< 130     Reference Raw Card Used
  SPD4_LRDIMM_MODULE_ATTRIBUTES               DimmModuleAttributes;        ///< 131     DIMM Module Attributes
  SPD4_LRDIMM_THERMAL_HEAT_SPREADER_SOLUTION  ThermalHeatSpreaderSolution; ///< 132     RDIMM Thermal Heat Spreader Solution
  SPD4_MANUFACTURER_ID_CODE                   RegisterManufacturerIdCode;  ///< 133-134 Register Manufacturer ID Code
  SPD4_LRDIMM_REGISTER_REVISION_NUMBER        RegisterRevisionNumber;      ///< 135     Register Revision Number
  SPD4_LRDIMM_ADDRESS_MAPPING_FROM_REGISTER_TO_DRAM                           AddressMappingFromRegisterToDram;                       ///< 136 Address Mapping from Register to DRAM
  SPD4_LRDIMM_REGISTER_OUTPUT_DRIVE_STRENGTH_FOR_CONTROL_COMMAND_ADDRESS      RegisterOutputDriveStrengthForControlCommandAddress;    ///< 137 Register Output Drive Strength for Control and Command Address
  SPD4_LRDIMM_REGISTER_OUTPUT_DRIVE_STRENGTH_FOR_CLOCK                        RegisterOutputDriveStrengthForClock;                    ///< 138 Register Output Drive Strength for Clock
  SPD4_LRDIMM_DATA_BUFFER_REVISION_NUMBER     DataBufferRevisionNumber;    ///< 139     Data Buffer Revision Number
  SPD4_LRDIMM_DRAM_VREFDQ_FOR_PACKAGE_RANK    DramVrefDQForPackageRank0;   ///< 140     DRAM VrefDQ for Package Rank 0
  SPD4_LRDIMM_DRAM_VREFDQ_FOR_PACKAGE_RANK    DramVrefDQForPackageRank1;   ///< 141     DRAM VrefDQ for Package Rank 1
  SPD4_LRDIMM_DRAM_VREFDQ_FOR_PACKAGE_RANK    DramVrefDQForPackageRank2;   ///< 142     DRAM VrefDQ for Package Rank 2
  SPD4_LRDIMM_DRAM_VREFDQ_FOR_PACKAGE_RANK    DramVrefDQForPackageRank3;   ///< 143     DRAM VrefDQ for Package Rank 3
  SPD4_LRDIMM_DATA_BUFFER_VREFDQ_FOR_DRAM_INTERFACE                   DataBufferVrefDQForDramInterface;               ///< 144     Data Buffer VrefDQ for DRAM Interface
  SPD4_LRDIMM_DATA_BUFFER_MDQ_DRIVE_STRENGTH_RTT_FOR_DATA_RATE        DataBufferMdqDriveStrengthRttForDataRateLe1866; ///< 145     Data Buffer MDQ Drive Strength and RTT for data rate <= 1866
  SPD4_LRDIMM_DATA_BUFFER_MDQ_DRIVE_STRENGTH_RTT_FOR_DATA_RATE        DataBufferMdqDriveStrengthRttForDataRateLe2400; ///< 146     Data Buffer MDQ Drive Strength and RTT for data rate <=2400
  SPD4_LRDIMM_DATA_BUFFER_MDQ_DRIVE_STRENGTH_RTT_FOR_DATA_RATE        DataBufferMdqDriveStrengthRttForDataRateLe3200; ///< 147     Data Buffer MDQ Drive Strength and RTT for data rate <=3200
  SPD4_LRDIMM_DRAM_DRIVE_STRENGTH                                     DramDriveStrength;                              ///< 148     DRAM Drive Strength
  SPD4_LRDIMM_DRAM_ODT_RTT_WR_RTT_NOM_FOR_DATA_RATE                   DramOdtRttWrRttNomForDataRateLe1866;            ///< 149     DRAM ODT (RTT_WR and RTT_NOM) for data rate <= 1866
  SPD4_LRDIMM_DRAM_ODT_RTT_WR_RTT_NOM_FOR_DATA_RATE                   DramOdtRttWrRttNomForDataRateLe2400;            ///< 150     DRAM ODT (RTT_WR and RTT_NOM) for data rate <= 2400
  SPD4_LRDIMM_DRAM_ODT_RTT_WR_RTT_NOM_FOR_DATA_RATE                   DramOdtRttWrRttNomForDataRateLe3200;            ///< 151     DRAM ODT (RTT_WR and RTT_NOM) for data rate <= 3200
  SPD4_LRDIMM_DRAM_ODT_RTT_PARK_FOR_DATA_RATE                         DramOdtRttParkForDataRateLe1866;                ///< 152     DRAM ODT (RTT_PARK) for data rate <= 1866
  SPD4_LRDIMM_DRAM_ODT_RTT_PARK_FOR_DATA_RATE                         DramOdtRttParkForDataRateLe2400;                ///< 153     DRAM ODT (RTT_PARK) for data rate <= 2400
  SPD4_LRDIMM_DRAM_ODT_RTT_PARK_FOR_DATA_RATE                         DramOdtRttParkForDataRateLe3200;                ///< 154     DRAM ODT (RTT_PARK) for data rate <= 3200
  SPD4_LRDIMM_DATA_BUFFER_VREFDQ_FOR_DRAM_INTERFACE_RANGE             DataBufferVrefDQForDramInterfaceRange;          ///< 155     Data Buffer VrefDQ for DRAM Interface Range
  SPD4_LRDIMM_DATA_BUFFER_DQ_DECISION_FEEDBACK_EQUALIZATION           DataBufferDqDecisionFeedbackEqualization;       ///< 156     Data Buffer DQ Decision Feedback Equalization
  UINT8                                                               Reserved[253 - 157 + 1];                        ///< 253-132 Reserved
  SPD4_CYCLIC_REDUNDANCY_CODE                                         Crc;                                            ///< 254-255 Cyclical Redundancy Code (CRC)
} SPD4_MODULE_LOADREDUCED;

typedef struct {
  UINT8                                                      Reserved0[191 - 128 + 1];              ///< 128-191  Reserved
  SPD4_NVDIMM_MODULE_PRODUCT_IDENTIFIER                      ModuleProductIdentifier;               ///< 192-193  Module Product Identifier
  SPD4_NVDIMM_SUBSYSTEM_CONTROLLER_MANUFACTURER_ID_CODE      SubsystemControllerManufacturerIdCode; ///< 194-195  Subsystem Controller Manufacturer's ID Code
  SPD4_NVDIMM_SUBSYSTEM_CONTROLLER_IDENTIFIER                SubsystemControllerIdentifier;         ///< 196-197  Subsystem Controller Identifier
  SPD4_NVDIMM_SUBSYSTEM_CONTROLLER_REVISION_CODE             SubsystemControllerRevisionCode;       ///< 198      Subsystem Controller Revision Code
  SPD4_NVDIMM_REFERENCE_RAW_CARD                             ReferenceRawCardUsed;                  ///< 199      Reference Raw Card Used
  SPD4_NVDIMM_MODULE_CHARACTERISTICS                         ModuleCharacteristics;                 ///< 200      Module Characteristics
  SPD4_NVDIMM_HYBRID_MODULE_MEDIA_TYPES                      HybridModuleMediaTypes;                ///< 201-202  Hybrid Module Media Types
  SPD4_NVDIMM_MAXIMUM_NONVOLATILE_MEMORY_INITIALIZATION_TIME MaximumNonVolatileMemoryInitializationTime; ///< 203 Maximum Non-Volatile Memory Initialization Time
  SPD4_NVDIMM_FUNCTION_INTERFACE_DESCRIPTOR                  FunctionInterfaceDescriptors[8];       ///< 204-219  Function Interface Descriptors
  UINT8                                                      Reserved[253 - 220 + 1];               ///< 220-253  Reserved
  SPD4_CYCLIC_REDUNDANCY_CODE                                Crc;                                   ///< 254-255  Cyclical Redundancy Code (CRC)
} SPD4_MODULE_NVDIMM;

typedef union {
  SPD4_MODULE_UNBUFFERED              Unbuffered;               ///< 128-255 Unbuffered Memory Module Types
  SPD4_MODULE_REGISTERED              Registered;               ///< 128-255 Registered Memory Module Types
  SPD4_MODULE_LOADREDUCED             LoadReduced;              ///< 128-255 Load Reduced Memory Module Types
  SPD4_MODULE_NVDIMM                  NonVolatile;              ///< 128-255 Non-Volatile (NVDIMM-N) Hybrid Memory Parameters
} SPD4_MODULE_SPECIFIC;

typedef struct {
  UINT8                               ModulePartNumber[348 - 329 + 1]; ///< 329-348 Module Part Number
} SPD4_MODULE_PART_NUMBER;

typedef struct {
  UINT8                               ManufacturerSpecificData[381 - 353 + 1]; ///< 353-381 Manufacturer's Specific Data
} SPD4_MANUFACTURER_SPECIFIC;

typedef UINT8                         SPD4_MODULE_REVISION_CODE;///< 349     Module Revision Code
typedef UINT8                         SPD4_DRAM_STEPPING;       ///< 352     Dram Stepping

typedef struct {
  SPD4_UNIQUE_MODULE_ID               ModuleId;                 ///< 320-328 Unique Module ID
  SPD4_MODULE_PART_NUMBER             ModulePartNumber;         ///< 329-348 Module Part Number
  SPD4_MODULE_REVISION_CODE           ModuleRevisionCode;       ///< 349     Module Revision Code
  SPD4_MANUFACTURER_ID_CODE           DramIdCode;               ///< 350-351 Dram Manufacturer ID Code
  SPD4_DRAM_STEPPING                  DramStepping;             ///< 352     Dram Stepping
  SPD4_MANUFACTURER_SPECIFIC          ManufacturerSpecificData; ///< 353-381 Manufacturer's Specific Data
  UINT8                               Reserved[2];              ///< 382-383 Reserved
} SPD4_MANUFACTURING_DATA;

typedef struct {
  UINT8                               Reserved[511 - 384 + 1];  ///< 384-511 Unbuffered Memory Module Types
} SPD4_END_USER_SECTION;

///
/// DDR4 Serial Presence Detect structure
///
typedef struct {
  SPD4_BASE_SECTION                   Base;                     ///< 0-127   Base Configuration and DRAM Parameters
  SPD4_MODULE_SPECIFIC                Module;                   ///< 128-255 Module-Specific Section
  UINT8                               Reserved[319 - 256 + 1];  ///< 256-319 Reserved
  SPD4_MANUFACTURING_DATA             ManufactureInfo;          ///< 320-383 Manufacturing Information
  SPD4_END_USER_SECTION               EndUser;                  ///< 384-511 End User Programmable
} SPD_DDR4;

#pragma pack (pop)
#endif