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

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

  Copyright (c) 2016, Intel Corporation. All rights reserved.<BR>
  This program and the accompanying materials
  are licensed and made available under the terms and conditions of the BSD License
  which accompanies this distribution.  The full text of the license may be found at
  http://opensource.org/licenses/bsd-license.php

  THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS,
  WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.

  @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