PHY Lite for Parallel Interfaces Intel® FPGA IP User Guide

ID 683716
Date 9/01/2021
Public

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2.2.4.3.3. Input DQ/DQS Delay Chains Maximum Values

The full range may not be usable. The absolute range is ranged from 0–511 (2 cycles). The usable range depends on PLL frequency, temperature, and voltage. To find the usable range, perform the write and read-back operations to ensure if that value applies or needs to be lowered.

Assuming that the usable range has a maximum value of k and you write a value A, you can read back the value based on the following conditions:

  • If A < k, where the value you write is under the upper limit, you read back the same value (readdata=A).
  • If A > k, where the value you write is over the upper limit, you read back the upper limit value. (readdata=k).