Stratix V Device Handbook: Volume 2: Transceivers

ID 683779
Date 11/23/2021
Document Table of Contents

3.2.4. Resetting the Receiver with the User-Coded Reset Controller During Device Power-Up Configuration

Follow this reset sequence to ensure a reliable receiver initialization after the initial power-up.

The numbers in the following figure correspond to the following numbered list, which guides you through the receiver reset sequence during device power-up.

  1. Assert mgmt_rst_reset at power-up to start the calibration IPs. Hold mgmt_rst_reset active for a minimum of two mgmt_clk_clock cycles. Hold rx_analogreset and rx_digitalreset active at power-up to hold the receiver in reset. You can deassert them after all the gating conditions are removed.
  2. After the receiver calibration completes, the rx_cal_busy status is deasserted.
  3. Deassert rx_analogreset after a minimum duration of trx_analogreset after rx_cal_busy is deasserted.
  4. rx_is_lockedtodata is a status signal from the receiver CDR indicating that the CDR is in the lock to data (LTD) mode. Ensure rx_is_lockedtodata is asserted and stays asserted for a minimum duration of tLTD before deasserting rx_digitalreset. If rx_is_lockedtodata is asserted and toggles, you must wait another additional tLTD duration before deasserting rx_digitalreset.
  5. Deassert rx_digitalreset after a minimum duration of tLTD after rx_is_lockedtodata stays asserted. Ensure rx_analogreset and rx_cal_busy are deasserted before deasserting rx_digitalreset.
The receiver is now out of reset and ready for operation.
Note: rx_is_lockedtodata might toggle when there is no data at the receiver input.
Note: rx_is_lockedtoref is a don't care when rx_is_lockedtodata is asserted.
Note: rx_analogreset must always be followed by rx_digitalreset.
Figure 83. Reset Sequence Timing Diagram for Receiver using the User-Coded Reset Controller during Device Power-Up