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AR# 39063

Spartan-6 FPGA Integrated Block for PCI Express - Why does trn_reset_n/user_reset_out(AXI) assert after sys_reset_n asserts?


Version Found: v1.1; v2.1
Version Resolved and other Known Issues: See (Xilinx Answer 45702).

The Spartan-6 FPGA Integrated Block User Guide says trn_reset_n/user_reset_out(AXI) should be asserted at the same time as sys_reset_n. However, during simulation, at time zero when sys_reset_n is asserted, trn_reset_n/user_reset_out(AXI) does not assert for approximatelyfour microseconds (this also occurs in hardware).


This difference occurs only at startup (time 0) and is due to logic within the block that ensures no contention is on the outputs during configuration. After initial startup, any further assertions of sys_reset_n cause trn_reset_n/user_reset_out(AXI) to assert simultaneously. This behavior is expected.

Revision History
01/18/2012 - Updated; added reference to 45072
07/06/2011 - Updated for v2.3
12/11/2010 - Initial release

Note: "Version Found" refers to the version the problem was first discovered. The problem might also exist in earlier versions, but no specific testing has been performed to verify earlier versions.

Linked Answer Records

Master Answer Records

Answer Number Answer Title Version Found Version Resolved
37939 Spartan-6 FPGA Integrated Block Wrapper for PCI Express (AXI) - Resolved issues in v2.1 N/A N/A

Associated Answer Records

AR# 39063
Date Created 12/08/2010
Last Updated 12/15/2012
Status Active
Type General Article
  • Spartan-6 LXT
  • Spartan-6 FPGA Integrated Endpoint Block for PCI Express ( PCIe )