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Altera_Forum
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16 years ago

PCIe Transmission Problem

Hi, I have the Altera Stratix II GX Dev Board. Im' using the Altera PCIe 9.0 IP Core with Avalon-ST Interface and I ran into some problems. I transfer 4 MB of data in 128 Byte blocks +...
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Altera_Forum
Icon for Honored Contributor rankHonored Contributor
16 years ago

Brett,

Did you solve this slowdown problem? I get similiar with SOPC PCIe x1 when DMA to Tx. I am testing with both Intel US15W/Z530 and AMD 785NB/745 Chipsets. The first 1k - 2k is full speed then settles into 16Mbyte/s on US15W and 64Mbyte/s on AMD. I see that it takes Altera's SOPC MM to PCIe bridge 6 clock cycles per QW, so I am running the DMA at 125MHz to compensate, but the PCIe core just pushes back and stalls more clock cycles.

Both platforms run 160Mbyte/s+ with non-SOPC instantiations.