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Honored Contributor
Honored ContributorDDR2: chip bits definition in local_addr[]
Can someone tell me what the definition of "chip bits" is for the local_addr field for the DDR2 SDRAM controller? The DDR and DDR2 SDRAM High-Performance Controller User Guide says for multipl...
Altera_ForumHonored Contributor
Honored ContributorA signal local_addr exists neither with the stated width nor with the exact name at the DDR2 HP controller interface (also not internally, as far as I know). So far the documentation is incorrect to my opinion. Let's say, local_addr is a virtual signal.
At the controller interface, a signal local_address is present. But it has alreay been reduced by the one or two column address LSB bits, so for a 2 GByte respectively 256M x 64 DIMM module, that uses 28 address bits internally (=log2(256M) ) local_address has 27 bits for a full rate or 26 bits for a half rate controller. I'm using a DIMM module of same size and organisation with a half rate controller, and it has local_address[25:0]
