Embedded Design Handbook

ID 683689
Date 8/28/2023
Public
Document Table of Contents

3.5.5.7.2. Full-Rate Mode

In full-rate mode, the internal Avalon interface to the SDRAM controller runs at the full external DDR SDRAM clock frequency. Use full-rate mode if your system logic is simple enough that it can easily achieve DDR SDRAM clock frequencies, or when running the system logic at half the clock rate of the SDRAM interface is too slow for your requirements.

When using full-rate mode, the local data width of the SDRAM controller is twice the data width of the physical DDR SDRAM. For example, if your SDRAM device is 16 bits wide, the internal Avalon data port of the SDRAM controller in full-rate mode is 32 bits wide. Again, this choice facilitate bursts to the SDRAM device.