17.5 Functional Description

The UDDRC converts system bus transactions into memory commands that are compliant with the DDR protocols.

The UDDRC performs the following functions:

• Accepts requests from the SoC core with system addresses and associated data for writes.
• Performs address mapping from system addresses to SDRAM addresses (rank, bank, bank group, row).
• Prioritizes requests to minimize the latency of reads (especially high priority reads) and maximize page hits.
• Ensures that the SDRAM is properly initialized.
• Ensures that all requests made to the SDRAM are legal (accounting for associated SDRAM constraints)
• Ensures that refreshes and other SDRAM maintenance requests are inserted as required.
• Controls when the SDRAM enters and exits the various power-saving modes appropriately.