F-Tile Architecture and PMA and FEC Direct PHY IP User Guide

ID 683872
Date 11/04/2024
Public
Document Table of Contents

3.8.5. Status Signals—Descriptions

Table 85.  Status Signal DescriptionsRefer to Variables Defining Bits for the Interfacing Ports in Port and Signal Reference for variable definitions.
Name Width Domain Direction Type Description
tx_pll_locked [N-1:0] N Asynchronous Output Direct

For FGT and FHT PMA TX PLLs, this signal is sticky. Once asserted, this signal does not deassert regardless of the lock state of the TX PLL until either the TX channel is reset (for FGT PMAs) or the device is reconfigured (for FHT PMAs).

This signal goes high under two conditions:
  1. TX PLL achieves lock to the reference clock when the reference clock is within the PPM threshold.
  2. In the presence of a reference clock, after approximately 150 µs (microsecond).

1’b1: The TX PLL has achieved lock at least once or, in the presence of a reference clock, after approximately 150 µs.

1’b0: The TX PLL has never achieved lock and, in presence of a reference clock, approximately 150 µs have not been reached.

To check the actual TX PLL locked state, Altera recommends following the Avalon® Memory-Mapped sequences provided in the Guidelines for Obtaining the Lock Status and Resetting the FGT and FHT TX PLLs section.

rx_is_lockedtoref [N-1:0] N Asynchronous Output Direct

CDR lock status signal.

  • 1’b1 – CDR is frequency locked to reference clock within the PPM threshold.
  • 1’b0 – CDR is not frequency locked within the PPM threshold.

Applicable to FGT PMA only. When lockedtodata stays high, the lockedtoref signal status is insignificant.

rx_is_lockedtodata [N-1:0] N Asynchronous Output Direct RX CDR data lock status signal.
  • 1’b0: CDR is not locked to data.
  • 1’b1: CDR is locked to data. Applicable to both FGT and FHT PMA.

When asserted, indicates that the CDR is in locked-to-data mode. When continuously asserted and does not switch between asserted and deasserted, you can confirm that the CDR is actually locked to data.