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  3. AR# 40426: MIG 7 Series v1.1 - Unrequested Reads are seen in simulation immediately after calibration completes

AR# 40426

MIG 7 Series v1.1 - Unrequested Reads are seen in simulation immediately after calibration completes

Description

When I run a MIG v1.1 Kintex-7 or Virtex-7 DDR3 SDRAM simulation, a series of unrequested reads (~2us) are seen after calibration completes (assertion of calib_complete). 

Why are these reads sent, and do they cause any issues?

Solution

The extra reads seen after calibration completes are expected behavior.

The calibration read leveling logic mistakenly issues the reads because the rdlvl_stg1_done signals are not asserted in time to stop the calibration logic from issuing additional reads.

These reads can be ignored.

They do not affect the functionality of calibration or user requested commands.

The code is to be modified in 7 Series MIG 1.2 (to be released with ISE Design Suite 13.2) to ensure that these reads do not occur. 

Linked Answer Records

Master Answer Records

Answer Number Answer Title Version Found Version Resolved
40050 MIG 7 Series v1.1 - Release Notes and Known Issues for ISE Design Suite 13.1 N/A N/A

Associated Answer Records

Answer Number Answer Title Version Found Version Resolved
40050 MIG 7 Series v1.1 - Release Notes and Known Issues for ISE Design Suite 13.1 N/A N/A
AR# 40426
Date 08/12/2014
Status Active
Type General Article
Devices
  • Kintex-7
  • Virtex-7
Tools
  • ISE Design Suite - 13.1
IP
  • MIG
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