Mode Register Set MRS and Emrs | Texas Instruments TMS320C642x DSP

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Peripheral Architecture

2.4.6Mode Register Set (MRS and EMRS)

DDR2 SDRAM contains mode and extended mode registers that configure the DDR2 memory for operation. These registers control burst type, burst length, CAS latency, DLL enable/disable (on DDR2 device), single-ended strobe, etc.

The DDR2 memory controller programs the mode and extended mode registers of the DDR2 memory by issuing MRS and EMRS commands. When the MRS or EMRS command is executed, the value on DDR_BA[1:0] selects the mode register to be written and the data on DDR_A[12:0] is loaded into the register. Figure 10 shows the timing for an MRS and EMRS command.

The DDR2 memory controller only issues MRS and EMRS commands during the DDR2 memory controller initialization sequence. See Section 2.13 for more information.

Figure 10. DDR2 MRS and EMRS Command

MRS/EMRS

DDR_CLK
DDR_CLK
DDR_CKE
DDR_CS
DDR_RAS
DDR_CAS
DDR_WE
DDR_A[12:0]	COL

DDR_BA[2:0] BANK

SPRUEM4A–November 2007

DDR2 Memory Controller

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Texas Instruments TMS320C642x DSP manual Mode Register Set MRS and Emrs, DDR2 MRS and Emrs Command

Contents

Users Guide Submit Documentation Feedback Contents List of Figures List of Tables Read This First Purpose of the Peripheral Features Supported Use Case Statement Functional Block DiagramIndustry Standards Compliance Statement Clock Source Clock Control 3 DDR2 Memory Controller Internal Clock Domains Clock ConfigurationPLLC2 Configuration Memory Map Pin Type Description Signal DescriptionsDDR2 Memory Controller Signal Descriptions Clock enable Active high Protocol Descriptions DDR2 Sdram CommandsTruth Table for DDR2 Sdram Commands Command Function Refresh Command Refresh Mode Deactivation Dcab and Deac Dcab Command Deac Command Activation Actv Actv Command DDR2 Read Command Read Command DDR2 WRT Command Write WRT Command DDR2 MRS and Emrs Command Mode Register Set MRS and Emrs Addressable Memory Ranges Memory Width and Byte Alignment Bit External Memory Endianness Support Address Mapping Bank Configuration Register Fields for Address MappingBit Field Bit Value Bit Description Logical Address-to-DDR2 Sdram Address Map for 16-bit Sdram Logical Address-to-DDR2 Sdram Address Map for 32-Bit Sdram Logical Address-to-DDR2 Sdram Address Map DDR2 Sdram Column, Row, and Bank Access DDR2 Memory Controller Fifo Description DDR2 Memory Controller Interface Command Ordering and Scheduling, Advanced Concept Possible Race Condition Command Starvation Urgency Level Description Self-Refresh ModeRefresh Scheduling Refresh Urgency Levels Reset Sources Reset ConsiderationsReset Signal Reset Source Auto-Initialization Sequence VTP IO Buffer Calibration DDR2 Memory Controller DDR2 Sdram Configuration by MRS CommandDDR2 Sdram Configuration by EMRS1 Command Initializing Configuration Registers Peripheral Architecture Interrupt Support Power ManagementDMA Event Support Emulation Considerations Supported Use Cases Connecting the DDR2 Memory Controller to DDR2 Memory Connecting DDR2 Memory Controller for 32-Bit Connection DDR2 Memory Refresh Specification Configuring Sdram Bank Configuration Register SdbcrSdram Bank Configuration Register Sdbcr Configuration Configuring Sdram Refresh Control Register Sdrcr DDR2 Data Register Field Manual Data Manual Formula Configuring Sdram Timing Registers Sdtimr and SDTIMR2Sdram Timing Register Sdtimr Configuration Sdram Timing Register 2 SDTIMR2 Configuration DDR PHY Control Register Ddrphycr Configuration Configuring DDR PHY Control Register DdrphycrRegister Field Name Description DDR VTP Register Mode D63-32D31-0 Acronym Register Description Sdram Status Register Sdrstat Field Descriptions Sdram Status Register SdrstatBit Field Sdram Bank Configuration Register Sdbcr Field Descriptions Sdram Bank Configuration Register SdbcrBit Field Value Description Reserved Reserved. Always write a 0 to this bit Sdram Refresh Control Register Sdrcr Field Descriptions Sdram Refresh Control Register Sdrcr Sdram Timing Register Sdtimr Field Descriptions Sdram Timing Register Sdtimr Sdram Timing Register 2 SDTIMR2 Field Descriptions Sdram Timing Register 2 SDTIMR2 Peripheral Bus Burst Priority Register Pbbpr Peripheral Bus Burst Priority Register Pbbpr Interrupt Raw Register IRR Field Descriptions Interrupt Raw Register IRR Interrupt Masked Register IMR Field Descriptions Interrupt Masked Register IMR Interrupt Mask Set Register Imsr Field Descriptions Interrupt Mask Set Register Imsr Interrupt Mask Clear Register Imcr Field Descriptions Interrupt Mask Clear Register Imcr DDR PHY Control Register Ddrphycr Field Descriptions DDR PHY Control Register Ddrphycr VTP IO Control Register Vtpiocr Field Descriptions VTP IO Control Register Vtpiocr DDR VTP Register Ddrvtpr Field Descriptions DDR VTP Enable Register DdrvtperDDR VTP Enable Register Ddrvtper Field Descriptions DDR VTP Register Ddrvtpr Additions/Modifications/Deletions Table A-1. Document Revision History Important Notice