Description

Solution

To work around this issue, make the following changes in the UCF file: 

1. Comment out the following constraint: 

 # NET "<snk_core_instant_name>/U0/pl4_lite_snk_reset0/rdclk0_rst_gen/reset_out_i*" MAXDELAY = 2.38 ns; 

2. Add the following constraints in the UCF file: 

INST "<snk_core_instant_name>/U0/pl4_lite_snk_reset0/rdclk0_rst_gen/reset_out*" TNM = snk_rdclk_reset; 
INST "<snk_core_instant_name>/U0/pl4_lite_snk_io0/virtex*/*IDDR" TNM = snk_iddr; 
TIMESPEC "TS_Snk_reset_iddr" = FROM "snk_rdclk_reset" TO "snk_iddr" "TS_RDClk_P"/ 4 DATAPATHONLY; 
TIMESPEC "TS_Snk_reset_ffs" = FROM "snk_rdclk_reset" TO "FFS" "TS_RDClk_P"; 

Essentially, the commented MAXELAY contraint is replaced with two constraints: the non-critical reset timing path (TS_Snk_reset_iddr) and the critical reset timing path (TS_Snk_reset_ffs). 

This issue has been fixed in v5.2 of the Core, available in ISE 12.1

Revision History 

06/24/2009 - Initial Release