GTS Ethernet Intel® FPGA Hard IP User Guide

ID 817676
Date 8/05/2024
Public
Document Table of Contents

4.3. Connect the Status Interface

The GTS Ethernet Intel® FPGA Hard IP core provides status signals to support visibility into the state of the IP core and the stability of IP core output clocks.

Figure 25.  GTS Ethernet Intel® FPGA Hard IP Status Signals
Table 24.  Status SignalsAll status signals except the i_stats_snapshot signal are asynchronous. All input signal names begin with i_ and all output signal names begin with o.
Signal Description
Input signals
i_stats_snapshot

Assert this signal to sample the current state of the statistics registers. Refer to Figure 28 for an example.

  • This signal is synchronous with the i_clk_tx clock.
Output signals
o_rx_block_lock

Indicates 66-bit block alignment for non-FEC and Firecode FEC variant and indicates codeword alignment for RS-FEC variant.

o_local_fault_status Asserted when the RX MAC detects a local fault: the RX PCS detected a problem that prevents it from receiving data.
o_remote_fault_status Asserted when the RX MAC detects a remote fault: the remote link partner has sent remote fault ordered sets indicating that it is unable to receive data.
o_rx_hi_ber Asserted to indicate the RX PCS is in a High BER state. The IP core uses this signal in auto negotiation and link training.
o_rx_pcs_fully_aligned Asserted when RX PCS is ready to receive data. This signal is only valid in PCS66 and PCS modes
o_rx_am_lock Asserted when RX PCS has found detected alignment markers and deskewed PCS virtual lanes (applicable for RS-FEC).
The diagram below shows the behavior of o_local_fault_status and o_remote_fault_status at startup.
Figure 26. Status Interface Behavior During Link Startup with Bidirectional Link FaultThe waveform displays the status signal behavior in the IP core at the startup.

Consider the following:

  • o_sys_pll_locked qualifies all of the signals in the above diagram.
  • o_tx_lanes_stable qualifies the following signals:
    • o_local_fault_status
    • o_remote_fault_status
    • o_tx_ready or o_tx_mii_ready.
  • The IP asserts o_local_fault_status and o_remote_fault_status at startup and keeps them high until both sides of the channel are ready.
  • o_local_fault_status stays high until the RX PCS is ready to receive data.
  • o_remote_fault_status stays high until the remote link partner indicates it can receive data.
  • o_tx_ready and o_tx_mii_ready stay low until o_local_fault_status and o_remote_fault_status are asserted.

When the core is in PCS-Only mode, or Link Fault is set to Unidirectional or Off, the figure below shows how the status signal typically behaves at startup.

Figure 27. Status Interface Behavior during Link Startup with Unidirectional or Link Fault DisableThe waveform displays status signals behavior in the IP core at the startup.
Consider the following:
  • o_sys_pll_locked qualifies all of the signals in the above timing diagram.
  • o_tx_lanes_stable qualifies o_tx_ready or o_tx_mii_ready.
  • o_tx_ready and o_tx_mii_ready do not wait for the status of the RX PCS.
Note: If link fault is set to Unidirectional mode, o_local_fault_status and o_remote_fault_status indicates the link fault status for the core, but the link fault status does not affect the TX channel.