www.ti.com

Peripheral Architecture

Figure 2. DDR2 Memory Controller Signals

DDR_CLK

DDR_CLK

DDR_CKE

DDR_CS

DDR_WE

DDR_RAS

DDR2DDR_CAS memory

controller DDR_DQM[3:0] DDR_DQS[3:0]

DDR_DQS[3:0]

DDR_BA[2:0]

DDR_A[13:0]

DDR_D[31:0]

DDR_ODT[1:0]

DDR_DQGATE[3:0]

DDR_VREF

 

Table 1. DDR2 Memory Controller Signal Descriptions

Pin

Description

DDR_D[31:0]

Bidirectional data bus. Input for data reads and output for data writes.

DDR_A[13:0]

External address output.

DDR_CS

Active-low chip enable for memory space CE0. DDR_CS is used to enable the DDR2 SDRAM memory

 

device during external memory accesses. DDR_CS pin stays low throughout the operation of the DDR2

 

memory controller; it never goes high. Note that this behavior does not affect the ability of the DDR2 memory

 

controller to access DDR2 SDRAM memory devices.

DDR_DQM[3:0]

Active-low output data mask.

DDR_CLK/

Differential clock outputs.

DDR_CLK

 

DDR_CKE

Clock enable (used for self-refresh mode).

DDR_CAS

Active-low column address strobe.

DDR_RAS

Active-low row address strobe.

DDR_WE

Active-low write enable.

DDR_DQS[3:0]/

Differential data strobe bidirectional signals.

DDR_DQS[3:0]

 

DDR_ODT[1:0]

On-die termination signals to external DDR2 SDRAM. These pins are reserved for future use and should not

 

be connected to the DDR2 SDRAM. Note: there are no on-die termination resistors implemented on the die

 

of this device.

DDR_BA[2:0]

Bank-address control outputs.

DDR_DQGATE[3:0]

Data strobe gate pins. These pins are used as a timing reference during memory reads. The

 

DDR_DQGATE0 and DDR_DQGATE2 pins should be routed out and connected to the DDR_DQGATE1 and

 

DDR_DQGATE3 pins, respectively. For more routing requirements on these pins, see the device-specific

 

data manual.

DDR_VREF

DDR2 Memory Controller reference voltage. This voltage must be supplied externally. See the

 

device-specific data manual for more details.

12

DSP DDR2 Memory Controller

SPRUF85 –October 2007

Submit Documentation Feedback

Page 12
Image 12
Texas Instruments TMS320C6452 DSP manual DDR2 Memory Controller Signal Descriptions, Pin Description