DDR SDRAM控制器的VHDL源代碼，含詳細設計文檔。
The DDR, DCM, and SelectI/O™ features in the Virtex™ -II architecture make it the perfect
choice for implementing a controller of a Double Data Rate (DDR) SDRAM. The Digital Clock
Manager (DCM) provides the required Delay Locked Loop (DLL), Digital Phase Shift (DPS),
and Digital Frequency Synthesis (DFS) functions. This application note describes a controller
design for a 16-bit DDR SDRAM. The application note and reference design are enhanced
versions of XAPP200 targeted to the Virtex-II series of FPGAs. At a clock rate of 133 MHz,
16-bit data changes at both clock edges. The reference design is fully synthesizable and
achieves 133 MHz performance with automatic place and route tools.
