Stratix® 10 Clocking and PLL User Guide

ID 683195
Date 7/11/2024
Public
Document Table of Contents

4.2.4.1. I/O PLL Dynamic Phase Shift Operation

To perform dynamic phase shift operation for an I/O PLL in the IOPLL IP core, follow these steps:

  1. Set the value for updn, cntsel[4..0], and num_phase_shift[2..0] ports.
  2. Assert phase_en port for at least two scanclk cycles.

Each phase_en pulse indicates one dynamic phase shift operation. The phase_done output goes low to indicate that dynamic phase shift is in progress. You can only assert the phase_en signal after the phase_done signal goes from low to high.

The updn, cntsel[4..0], and num_phase_shift[2..0] ports are synchronous to the scanclk cycle.

When the phase_done signal transitions from high to low, the phase_done signal is synchronous to the rising edge of the scanclk signal. The transition from low to high is asynchronous to the scanclk signal.

Depending on the VCO and scanclk frequency, the low time of the phase_done signal may be greater than or less than one scanclk cycle.