SDR SDRAM Controller August 2002, ver. 1.1 1M-WP-SDR-1.1 IntroductionThe single data rate (SDR) synchronous dynamic random access memory (SDRAM) controller provides a simplified interface to industry standard SDR SDRAM. The SDR SDRAM Controller is available in either Verilog HDL or VHDL and is optimized for the Altera® APEX™ architecture. The SDR SDRAM Controller supports the followingfeatures:■ Burst lengths of 1, 2, 4, or 8 data words■ CAS latency of 2 or 3 clock cycles■ 16-bit programmable refresh counter used for automatic refresh■ 2-chip selects for SDRAM devices■ Supports the NOP, READA, WRITEA, AUTO_REFRESH, PRECHARGE, ACTIVATE, BURST_STOP,and LOAD_MR commands■ Support for full-page mode operation■ Data mask line for write operations■ PLL to increase system performance■ Support for data-path widths of 16, 32, and 64 bitsFigure 1 shows a system-level diagram of the SDR SDRAM Controller.