External Memory Interface Handbook Volume 2: Design Guidelines

ID 683385
Date 5/08/2017
Document Table of Contents

12.3. Sequencer

The UniPHY IP soft memory PHY supports the following two types of sequencer used for QDRII and QDRII+ SRAM, and RLDRAM II calibration:
  • RTL-based sequencer
  • Nios II-based sequencer

The RTL-based sequencer performs FIFO calibration that includes adjusting the valid‑prediction FIFO (VFIFO) and latency FIFO (LFIFO) length. In addition to the FIFO calibration, the Nios II-based sequencer also performs I/O calibration that includes adjusting delay chains and phase settings to center-align the data pins with respect to the strobes that sample them. I/O calibration is required for memory interfaces running at higher frequencies to increase read and write margins.

Because the RTL-based sequencer performs a relatively simpler calibration process, it does not require a Nios II processor. For this reason, utilization of resources such as LEs and RAMs is lower than with the Nios II-based sequencer.

For more information about the RTL-based sequencer and Nios II-based sequencer, refer to the Functional Description—UniPHY chapter in volume 3 of the External Memory Interface Handbook .

For more information about the calibration process, refer to the “UniPHY Calibration Stages” section in the Functional Description—UniPHY chapter of the External Memory Interface Handbook.

Did you find the information on this page useful?

Characters remaining:

Feedback Message