【应用手册】External Memory Interfaces in Stratix & Stratix GX Devices Stratix® and Stratix GX devices support a broad range of external memory interfaces such as double data rate (DDR) SDRAM, RLDRAM II, quad data rate (QDR) SRAM, QDRII SRAM, zero bus turnaround (ZBT) SRAM, and single data rate (SDR) SDRAM. The dedicated phase-shift circuitry allows the Stratix and Stratix GX devices to interface at twice the system clock speed with an external memory (up to 200 MHz/400 Mbps). 3. External Memory Interfaces in Stratix & Stratix GX Devices S52008-3.3 Introduction Stratix and Stratix GX devices support a broad range of external memory interfaces such as double data rate (DDR) SDRAM, RLDRAM II, quad data rate (QDR) SRAM, QDRII SRAM, zero bus turnaround (ZBT) SRAM, and single data rate (SDR) SDRAM. The dedicated phase-shift circuitry allows the Stratix and Stratix GX devices to interface at twice the system clock speed with an external memory (up to 200 MHz/400 Mbps). ……