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AR# 40778

MIG Spartan-6 MCB - Termination and I/O Standard Guidelines

Description

The MIG Spartan-6 MCB designs are characterized with specific termination schemes and I/O Standards.The "Designing with the MCB" > "PCB Layout Considerations" section of the Spartan-6 FPGA Memory Controller User Guide (UG388) includes information on termination guidelines and the MIG design's usage of I/O Standards:http://www.xilinx.com/support/documentation/ip_documentation/ug388.pdf

NOTE: This Answer Record is part of the Xilinx MIG Solution Center (Xilinx Answer 34243). The Xilinx MIG Solution Center is available to address all questions related to MIG. Whether you are starting a new design with MIG or troubleshooting a problem, use the MIG Solution Center to guide you to the right information.

Solution

Termination

Running SI Simulation using IBIS Models is highly recommended for all memory designs. The user guide section noted above includes information on the following:

  • Termination guidelines for uni- and bi-directional signals
  • Where termination resistors should be placed
  • How to properly terminate ODT, CKE, and RESET to adhere to the DDR, DDR2 and DDR3 Memory standards initialization processes
  • Usage of ODT (at the memory) andinput termination(at the FPGA)

Please read the entire section noted above for full details.

See also:

(Xilinx Answer 38623)MIG Spartan-6 MCB - Why is ODT issued late by the MCB when operating in DDR2 mode 400 Mbps?
(Xilinx Answer 38819)MIG v3.6, Spartan-6 MCB - Does the MCB support Dynamic ODT?
(Xilinx Answer 38651)MIG 3.6 Spartan-6 - DDR termination recommendation
(Xilinx Answer 41721)MIG Spartan-6 MCB DDR3 SDRAM - Is "OUT_TERM = UNTUNED_50" UCF constraint supported for MCB design?

I/O Standards

The MIG tool creates the UCF using the appropriate standard based on input from the GUI. The MIGUCF can be found in either the "example_design/par" or "user_design/par" directories. Only the I/O standards provided in the MIG UCFs have been tested in hardware during MIG characterization.

Linked Answer Records

Child Answer Records

Answer Number Answer Title Version Found Version Resolved
41721 MIG Spartan-6 MCB DDR3 SDRAM - Is the "OUT_TERM = UNTUNED_50" UCF constraint supported for MCB designs? N/A N/A

Associated Answer Records

AR# 40778
Date Created 08/22/2011
Last Updated 12/15/2012
Status Active
Type General Article
Devices
  • Spartan-6 LX
  • Spartan-6 LXT
IP
  • MIG