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2.1.1. Selecting Your External Memory Device
2.1.2. Selecting Your FPGA
2.1.3. Planning Your Pin Requirements
2.1.4. Planning Your FPGA Resources
2.1.5. Determining Your Board Layout
2.1.6. Specifying Parameters for Your External Memory Interface
2.1.7. Performing Functional Simulation
2.1.8. Adding Design Constraints
2.1.9. Compiling Your Design and Verifying Timing
2.1.10. Verifying and Debugging External Memory Interface Operation
3.1. DDR SDRAM Features
3.2. DDR2 SDRAM Features
3.3. DDR3 SDRAM Features
3.4. QDR, QDR II, and QDR II+ SRAM Features
3.5. RLDRAM II and RLDRAM 3 Features
3.6. LPDDR2 Features
3.7. Memory Selection
3.8. Example of High-Speed Memory in Embedded Processor
3.9. Example of High-Speed Memory in Telecom
3.10. Document Revision History
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3.1. DDR SDRAM Features
Double data rate (DDR) SDRAM is a 2n prefetch architecture with two data transfers per clock cycle. It uses a single-ended strobe, DQS, which is associated with a group of data pins, DQ, for read and write operations. Both DQS and DQ are bidirectional ports. Address ports are shared for read and write operations.
The desktop computing market has positioned DDR SDRAM as a mainstream commodity product, which means this memory is very low-cost. DDR SDRAM is also high-density and low-power. Relative to other high-speed memories, DDR SDRAM has higher latency-they have a multiplexed address bus, which reduces the pin count (minimizing cost) at the expense of a longer and more complex bus cycle.