The DDR and DDR2 SDRAM controllers handle the complex aspects of using DDR and DDR2 SDRAM—initializing the memory devices, managing SDRAM banks, and keeping the devices refreshed at appropriate intervals. The controllers translate read and write requests from the local interface into all the necessary SDRAM command signals.
Whether you use the IP Toolbench in the Intel® Qsys IP or the Intel Quartus® Prime design software, it generates an example design, instantiates a phase-locked loop (PLL), an example driver, and your DDR/DDR2 SDRAM Controller custom variation. The example design is a fully-functional example design that can be simulated, synthesized, and used in hardware. The example driver is a self-test module that issues read and write commands to the controller and checks the read data to produce the pass/fail and test complete signals.
You can replace the DDR/DDR2 SDRAM controller encrypted control logic in the example instance with your own custom logic, which allows you to use the Intel FPGA clear-text datapath with your own control logic.