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Altera_Forum
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9 years ago

PC doesn't boot when RXM_BAR4 connects ext DDR3 cntrlr in AVMM DMA PCIe Qsys design

Hi, I am stumped with this one. I have modified the Altera stratix V PCIe AVMM DMA reference design to include a UniPhy based external DDR3 controller to the Qsys. The target fpga is sitting ...
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Altera_Forum
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9 years ago

Sounds like you are trying to create a larger BAR than the BIOS can allocate resource to.

A 4GB BAR would have to be 64bit address - and recognised by the BIOS as such, I'm not sure PC BIOS support them.

I'd guess that all the memory BAR (for all cards) have to fit into either 512M or 1G at the top of the 32bit address space.

You might manage a 256M window into the bottom of the DDR (feed the avalon signals through a conduit to force the high address bits to zero).