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Using the DDR2 Memory Controller
3Using the DDR2 Memory Controller
The following sections show various ways to connect the DDR2 memory controller to DDR2 memory devices. The steps required to configure the DDR2 memory controller for external memory access are also described.
3.1Connecting the DDR2 Memory Controller to DDR2 SDRAM
Figure 17, Figure 18, and Figure 19 show a high-level view of the three memory topologies
∙A 32-bit wide configuration interfacing to two 16-bit wide DDR2 SDRAM devices
∙A 16-bit wide configuration interfacing to a single 16-bit wide DDR2 SDRAM device
∙A 16-bit wide configuration interfacing to two 8-bit wide DDR2 SDRAM devices
All DDR2 SDRAM devices must be complaint to the JESD79D-2A standard.
Not all of the memory topologies shown may be supported by your device. See the device-specific data manual for more information.
Printed circuit board (PCB) layout rules and connection requirements between the DSP and the memory device exist and are described in a separate document. See the device-specific data manual for more information. The ODT output pins of the DDR2 memory controller must not be connected to the ODT input pins of DDR2 memory devices. Instead, the ODT input pins of the DDR2 memory devices should be connected to ground and the ODT output pins of the DDR2 memory controller must be left unconnected. The ODT output pins of the DDR2 memory controller are reserved for future use.
SPRUF85 | DSP DDR2 Memory Controller | 29 |