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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] ![]()
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DDR_DQS[3:0] ![]()
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DDR_BA[2:0] ![]()
DDR_A[13:0] ![]()
DDR_D[31:0] ![]()
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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 | |
  | 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]  | |
DDR_CLK/  | Differential clock outputs.  | 
DDR_CLK  | 
  | 
DDR_CKE  | Clock enable (used for   | 
DDR_CAS  | |
DDR_RAS  | |
DDR_WE | |
DDR_DQS[3:0]/  | Differential data strobe bidirectional signals.  | 
DDR_DQS[3:0]  | 
  | 
DDR_ODT[1:0]  | |
  | be connected to the DDR2 SDRAM. Note: there are no   | 
  | of this device.  | 
DDR_BA[2:0]  | |
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   | 
  | data manual.  | 
DDR_VREF | DDR2 Memory Controller reference voltage. This voltage must be supplied externally. See the  | 
  | 
12  | DSP DDR2 Memory Controller  | SPRUF85   |