External Memory Interface Handbook Volume 3: Reference Material

ID 683841
Date 7/24/2019
Public
Document Table of Contents

1.17.9. Calibration Time

The time needed for calibration varies, depending on many factors including the interface width, the number of ranks, frequency, board layout, and difficulty of calibration. In general, designs using the Nios II-based sequencer will take longer to calibrate than designs using the RTL-based sequencer.

The following table lists approximate typical and maximum calibration times for various protocols.

Table 20.  Approximate Calibration Times

Protocol

Typical Calibration Time

Maximum Calibration Time

DDR2, DDR3, LPDDR2, RLDRAM 3

50-250 ms

Can take several minutes if the interface is difficult to calibrate, or if calibration initially fails and exhausts multiple retries.

QDR II/II+, RLDRAM II (with Nios II-based sequencer)

50-100 ms

Can take several minutes if the interface is difficult to calibrate, or if calibration initially fails and exhausts multiple retries.

QDR II/II+, RLDRAM II (with RTL-based sequencer)

<5 ms

<5 ms

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