Altera Stratix II GX PCI Express Development Board Manual de usuario descargar pdf (Pagina 58)

2–48 Reference Manual Altera Corporation

Stratix II GX PCI Express Development Board August 2006

Off-Chip Memory

QDRII SRAM

The board uses a burst-of-four QDRII SRAM memory device for

high-speed, low-latency memory access, with addressing for up to a

72-MB device.

The QDRII device has separate read and write data ports with DDR

interfaces at up to 300 MHz. Burst-of-4 devices have higher data rates due

to the longer sequential addressing. The QDRII interface supports over

21 Gb/s of throughput at 300 MHz (600 MB/s x 36 pins). The bandwidth

doubles to over 42 Gb/s when combined read and write bandwidths are

considered.

The QDRII interface signals do not have board-level termination

resistors. Instead, the QDRII interface is terminated using the 50 Ω output

impedance settings available on both the Stratix II GX device and the

QDRII SRAM device. This approach simplifies board routing and lowers

power consumption.

ddr2_dqs[1] AU12

ddr2_dqs[2] AT14

ddr2_dqs[3] AP15

ddr2_dqs[4] AV18

ddr2_dqs[5] AU23

ddr2_dqs[6] AT25

ddr2_dqs[7] AU28

ddr2_dqs[8] AW33

ddr2_odt AN25

ddr2_rasn AJ27

ddr2_sync_clk_in AW20

ddr2_sync_clk_out AV36

ddr2_wen AL13

Table 2–30. DDR2 SRAM Pin-Out (Part 5 of 5)

Schematic Signal Name Stratix II GX Device Pin Number

1 2 ... 53 54 55 56 57 58 59 60 61 62 63 ... 69 70

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Altera Stratix II GX PCI Express Development Board Manual de usuario Pagina 58