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Altera_Forum
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16 years ago

issuing memory write request from PCI Express endpoint

Hi! I'm trying to send data from my PCI Express endpoint (StratixIV Hard IP) to the root port memory. For that I would need the enpoints device ID (to put it in the requester ID field of the he...
Altera_Forum's avatar
Altera_Forum
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15 years ago

Practically you don’t have to care about the contents of cfg_busdev unless you are a root port or you implement multiple functions. Just use it whenever sending a TLP. If you want to know more about cfd_busdev, look into the PCIe Specification, Section labelled »Transaction Descriptor – Transaction ID Field«. The 8 MS bits are the PCI Bus Number, then there are 5 bits Device Number, and the 3 LSBs are the Function Number.