17.5.3 Address Mapper

Read and write requests are provided to the UDDRC with a system address. The system address is the command address of a transaction as presented on one of the data ports. The UDDRC converts this system address to a physical address. It maps the system address to the SDRAM rank, bank, row, and column addresses.

The first part of the mapping is conversion of system address to AXI byte address. The controller maps disjoint address regions to internal consecutive addresses. Otherwise, the controller assumes that the DRAM is always mapped as a monolithic block. For more information about this, see System Address Regions.

The second part of this mapping is the conversion of AXI byte address to HIF word address. This is performed in the XPI block, and is applicable to AXI configurations only. For more information about this, see Application to HIF Address Mapping.

The last part is the conversion of HIF word address to SDRAM address. A flexible address mapper maps the HIF word address to the SDRAM rank/bank/bank group/row/column address. This address mapper is located within the DDRC.

The address mapping to be used depends on the use-case. The UDDRC provides a set of registers that allows flexible re-programming of logical to physical address mapping. For more information about this, see HIF Address to SDRAM Address Mapping.

The following figure explains the conversion of AXI to HIF to the SDRAM rank/bank/row/column/bank group addresses.