Stratix V Avalon-ST Interface for PCIe Solutions: User Guide

ID 683093
Date 5/03/2019
Public
Document Table of Contents

Hard IP for PCI Express and Application Logic Reset Sequence Your Application Layer can instantiate a module with logic that implements the timing diagram shown below to generate app_rstn, which resets the Application Layer logic.

This reset sequence includes the following steps:

  1. After pin_perst or npor is released, the Hard IP reset controller waits for pld_clk_inuse to be asserted.
  2. csrt and srst are released 32 cycles after pld_clk_inuse is asserted.
  3. The Hard IP for PCI Express deasserts the reset_status output to the Application Layer.
  4. The altpcied_<device>v_hwtcl.sv deasserts app_rstn  32 pld_clkcycles after reset_status is released.
    Note: reset_status may be toggling until the host and its receivers are detected during the link training sequence (ltssmstate[4:0] = 0x02).
RX Transceiver Reset Sequence

The RX transceiver reset sequence includes the following steps:

  1. After rx_pll_locked is asserted, the LTSSM state machine transitions from the Detect.Quiet to the Detect.Active state.
  2. When the pipe_phystatus pulse is asserted and pipe_rxstatus[2:0] = 3, the receiver detect operation has completed.
  3. The LTSSM state machine transitions from the Detect.Active state to the Polling.Active state.
  4. The Hard IP for PCI Express asserts rx_digitalreset. The rx_digitalreset signal is deasserted after rx_signaldetect is stable for a minimum of 3 ms.
TX Transceiver Reset Sequence

The TX transceiver reset sequence includes the following steps:

  1. After npor is deasserted, the IP core deasserts the npor_serdes input to the TX transceiver.
  2. The SERDES reset controller waits for pll_locked to be stable for a minimum of 127 pld_clk cycles before deasserting tx_digitalreset.

For descriptions of the available reset signals, refer to Reset Signals, Status, and Link Training Signals.