Texas Instruments TMS320C6455 manual 11.1 DDR2 Sdram Device Mode Register Configuration Values

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Peripheral Architecture

•Following a write to the two least-significant bytes in the SDRAM configuration register (SDCFG); see Section 2.11.3.

At the end of the initialization sequence, the DDR2 memory controller performs an auto-refresh cycle, leaving the DDR2 memory controller in an idle state with all banks deactivated.

When the initialization section is started automatically after a hard or soft reset, commands and data stored in the DDR2 memory controller FIFOs are lost. However, when the initialization sequence is initiated by a write to the two least-significant bytes in SDCFG, data and commands stored in the DDR2 memory controller FIFOs are not lost and the DDR2 memory controller ensures read and write commands are completed before starting the initialization sequence.

2.11.1DDR2 SDRAM Device Mode Register Configuration Values

The DDR2 memory controller initializes the mode register and extended mode register 1 of the memory device with the values shown on Table 9 and Table 10. The DDR2 SDRAM extended mode registers 2 and 3 are configured with a value of 0h.

Table 9. DDR2 SDRAM Mode Register Configuration

Mode

 

 

 

Register Bit

Mode Register Field

Init Value

Description

 

 

 

 

12

Power-down Mode

0

Active power-down exit time bit. Configured for Fast exit.

 

 

 

 

11-9

Write Recovery

SDTIM1.T_WR

Write recovery bits for auto-precharge. Initialized using

 

 

 

the T_WR bits of the SDRAM timing 1 register (SDTIM1).

 

 

 

 

8

DLL Reset

0

DLL reset bits. DLL is not in reset.

 

 

 

 

7

Mode

0

Operating mode bit. Normal operating mode is always

 

 

 

selected.

 

 

 

 

6-4

CAS Latency

SDCFG.CL

CAS latency bits. Initialized using the CL bits of the

 

 

 

SDRAM configuration register (SDCFG).

 

 

 

 

3

Burst Type

0

Burst type bits. Sequential burst mode is always used.

 

 

 

 

2-0

Burst Length

3h

Bust length bits. A burst length of 8 is always used.

 

 

 

 

Table 10. DDR2 SDRAM Extended Mode Register 1 Configuration

Mode

 

 

 

 

 

 

 

 

 

 

 

Register Bit

Mode Register Field

Init Value

 

Description

 

 

 

 

 

12

Output Buffer Enable

0

 

Output buffer enable bits. Output buffer is always

 

 

 

 

 

enabled.

 

 

 

 

 

 

 

 

11

RDQS Enable

0

 

 

 

enable bits. Always initialized to 0

 

 

signals

 

RDQS

(RDQS

 

 

 

 

 

disabled.)

 

 

 

 

 

 

 

 

 

 

 

 

10

 

enable

0

 

 

enable bit. Always initialized to 0

 

 

signals

DQS

 

DQS

(DQS

 

 

 

 

 

enabled.)

 

 

 

 

 

 

 

 

 

 

 

 

9-7

OCD Operation

0h

 

Off-chip driver impedance calibration bits. This bit is

 

 

 

 

 

always initialized to 0h.

 

 

 

 

 

 

 

 

 

 

 

 

6

ODT Value (Rtt)

0

 

On-die termination effective resistance (Rtt) bit. This bit is

 

 

 

 

 

reserved for future use.

 

 

 

 

 

 

 

 

 

 

 

 

5-3

Additive Latency

0h

 

Additive latency bits. Always initialized to 0h (no additive

 

 

 

 

 

latency).

 

 

 

 

 

 

 

 

 

 

 

 

2

ODT Value (Rtt)

1

 

On-die termination effective resistance (Rtt) bit. This bit is

 

 

 

 

 

reserved for future use.

 

 

 

 

 

 

 

 

 

 

 

 

1

Output Driver Impedance

SDCFG.DDR_DRIVE

 

Output driver impedance control bits. Initialized using the

 

 

 

 

 

DDR_DRIVE bit of the SDRAM configuration register

 

 

 

 

 

(SDCFG).

 

 

 

 

 

 

 

 

 

 

 

 

0

DLL Enable

0

 

DLL enable/disable bits. DLL is always enabled.

 

 

 

 

 

 

 

 

 

 

 

 

SPRU970G – December 2005 – Revised June 2011

C6455/C6454 DDR2 Memory Controller

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Copyright © 2005–2011, Texas Instruments Incorporated

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Contents Users Guide Submit Documentation Feedback Contents List of Figures List of Tables Submit Documentation Feedback Read This First Read This First Purpose of the Peripheral FeaturesFunctional Block Diagram Industry Standards Compliance Statement Memory Map Signal DescriptionsClock Control Pin Description DDR2 Memory Controller Signal DescriptionsTruth Table for DDR2 Sdram Commands DDR2 Sdram CommandsCommand Function Protocol DescriptionsDDR2 MRS and Emrs Command Mode Register Set MRS and EmrsRefresh Command Refresh ModeActivation Actv Actv CommandDeactivation Dcab and Deac Dcab CommandDeac Command DDR2 Read Command Read CommandMemory Width, Byte Alignment, and Endianness Write WRT CommandAddressable Memory Ranges Address Type Generated by DDR2Address Mapping Bank Configuration Register Fields for Address MappingBit Field Bit Value Bit Description IbankLogical Address-to-DDR2 Sdram Address Map for 32-Bit Sdram Logical Address-to-DDR2 Sdram Address Map DDR2 Memory Controller Fifo Description DDR2 Memory Controller InterfaceCommand Ordering and Scheduling, Advanced Concept DDR2 Memory Controller Fifo Block Diagram Command Starvation Possible Race Condition Refresh SchedulingRefresh Urgency Levels Urgency Level DescriptionReset Considerations Self-Refresh ModeDevice and DDR2 Memory Controller Reset Relationship DDR2 Memory Controller Reset Effect Initiated byDDR2 Sdram Mode Register Configuration 11.1 DDR2 Sdram Device Mode Register Configuration ValuesDDR2 Sdram Extended Mode Register 1 Configuration Mode Register Field11.3 DDR2 Sdram Initialization After Register Configuration 11.2 DDR2 Sdram Initialization After ResetInterrupt Support Edma Event SupportConnecting the DDR2 Memory Controller to DDR2 Sdram Using the DDR2 Memory ControllerConnecting to Two 16-Bit DDR2 Sdram Devices Connecting to a Single 16-Bit DDR2 Sdram Device Connecting to Two 8-Bit DDR2 Sdram Devices Sdcfg Configuration Programming the Sdram Configuration Register SdcfgProgramming the Sdram Refresh Control Register Sdrfc FieldSdrfc Configuration DDR2 Memory Refresh SpecificationConfiguring Sdram Timing Registers SDTIM1 and SDTIM2 SDTIM1 ConfigurationDmcctl Configuration SDTIM2 ConfigurationDDR2 Sdram Data Register Field Sheet Parameter Name DescriptionRegister Description DDR2 Memory Controller RegistersOffset Bit Field Value Description Module ID and Revision Register MidrModule ID and Revision Register Midr Field Descriptions Ifrdy DDR2 Memory Controller Status Register DmcstatSdram Configuration Register Sdcfg Field Descriptions Sdram Configuration Register SdcfgSequence. Values 4-7 are reserved for this field Sdram Refresh Control Register Sdrfc Field Descriptions Sdram Refresh Control Register SdrfcSdram Timing 1 Register SDTIM1 Field Descriptions Sdram Timing 1 Register SDTIM1Trfc TRP Trcd TWR Tras TRC TrrdUsing this formula Sdram Timing 2 Register SDTIM2 Field Descriptions Sdram Timing 2 Register SDTIM2Todt Txsnr Txsrd Trtp TckePrioraise Burst Priority Register BprioBurst Priority Register Bprio Field Descriptions DDR2 Memory Controller Control Register Dmcctl DDR2 Memory Controller Control Register DmcctlRevision History DSP Products ApplicationsRfid TI E2E Community Home
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