Intel® Cyclone® 10 GX Transceiver PHY User Guide

ID 683054
Date 4/14/2023
Document Table of Contents

7.5.2. Fractional PLL Recalibration

Follow these steps to recalibrate the fPLL:

  1. Request user access to the internal configuration bus by writing 0x2 to offset address 0x0[7:0].
  2. Wait for reconfig_waitrequest to be deasserted (logic low) or wait until capability register of PreSICE Avalon-MM interface control 0x280[2]=0x0.
  3. To recalibrate the fPLL, Read-Modify-Write 0x1 to bit[1] of address 0x100 of the fPLL.
  4. Release the internal configuration bus to PreSICE to perform recalibration by writing 0x1 to offset address 0x0[7:0].
  5. Periodically check the *cal_busy output signals or read the capability registers 0x280[1] to check *cal_busy status until calibration is complete.
Note: If you are recalibrating your fPLL and have ATX PLL used on the same side of the device, follow the fPLL-to-ATX PLL spacing guideline as stated in the "Transmit PLLs Spacing Guideline when using ATX PLLs and fPLLs" section under PLLs and Clock Networks chapter.