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AR# 44412

7 Series Integrated Wrapper for LogiCORE IP OBSAI v5.1 - Should the transceiver transmit and receive elastic buffers be enabled?

Description

Should the transceiver transmit and receive elastic buffers be enabled?

Solution

(Xilinx Answer 43244) recommends that Tx and Rx elastic buffers be enabled.

For OBSAI, these buffers are normally bypassed to allow accurate latency measurement for Round Trip Time (RTT) measurement, etc. Enabling the elastic buffers results in inaccurate RTT measurements.

In <component_name>/example_design/gtx_and_clocks/gtx/gtx_wrapper_gt.vhd, modify the Rx and Tx Elastic Buffer sections as follows:

-------- Receive Ports - RX Elastic Buffer and Phase Alignment Ports -------

RXBUFRESET => tied_to_ground_i,
RXBUFSTATUS => open,
RXDDIEN => tied_to_ground_i,
RXDLYBYPASS => tied_to_vcc_i,
RXDLYEN => tied_to_ground_i,
RXDLYOVRDEN => tied_to_ground_i,
RXDLYSRESET => tied_to_ground_i,
RXDLYSRESETDONE => open,
RXPHALIGN => tied_to_ground_i,
RXPHALIGNDONE => open,
RXPHALIGNEN => tied_to_ground_i,
RXPHDLYPD => tied_to_ground_i,
RXPHDLYRESET => tied_to_ground_i,
RXPHMONITOR => open,
RXPHOVRDEN => tied_to_ground_i,
RXPHSLIPMONITOR => open,
RXSTATUS => open,

----------- Transmit Ports - TX Elastic Buffer and Phase Alignment ---------

TXBUFSTATUS => open,
TXDLYBYPASS => tied_to_vcc_i,
TXDLYEN => tied_to_ground_i,
TXDLYHOLD => tied_to_ground_i,
TXDLYOVRDEN => tied_to_ground_i,
TXDLYSRESET => tied_to_ground_i,
TXDLYSRESETDONE => open

For Release Notes and Known Issues for the LogiCORE IP OBSAI, see (Xilinx Answer 36971).

Linked Answer Records

Master Answer Records

Answer Number Answer Title Version Found Version Resolved
36971 LogiCORE IP OBSAI - Release Notes and Known Issues N/A N/A

Associated Answer Records

AR# 44412
Date Created 01/23/2012
Last Updated 05/22/2012
Status Active
Type Known Issues
IP
  • OBSAI