DDR SDRAM Controller

The DDR SDRAM uses double data rate architecture to achieve high-speed data transfers. DDR SDRAM ( referred to as DDR) transfers data on both the rising and falling edge of the clock. This reference design provides an implementation of the DDR memory controller implemented in Lattice ORCA Series 4 FPGA device. This DDR controller is typically implemented in a system between the DDR and the bus master. Figure 1 shows the relationship of the controller between the bus master and the DDR. The bus master could be either a microprocessor like Intel's i960 or a user's proprietary module interface. For illustration purpose, the Micron's 4M x 8 x 4Banks DDR SDRAM is chosen for this design. The design was verified using Micron SDRAM simulation model.