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AR# 15829

6.1i MAP - "ERROR:LIT - Flop FLOP symbol "q" (output signal=q_obuf) has INITSTATE=1 and CLR dominates PRE. Virtex does not support this flop."

Description

Keywords: LIT, Flop, symbol, CLR dominates PRE, Virtex, support, architecture

Urgency: Standard

General Description:
When I use an FDCPE register, the following valid error occurs:

"ERROR:LIT - Flop FLOP symbol "q" (output signal=q_obuf) has INITSTATE=1 and CLR dominates PRE. Virtex does not support this flop. To convert the flop into PRE dominates CLR, please set the environment variable XIL_MAP_FDCPE_I1_TO_FDPCE_I1."

If the specified variable is set, MAP fails and reports:

"ERROR:LIT - Flop FLOP symbol "q" (output signal=q_obuf) has INITSTATE=1 and CLR dominates PRE. Virtex does not support this flop. The flop is converted to PRE dominates CLR."

Solution

The message is intended as a warning, but it incorrectly causes MAP to fail. This problem was introduced in 5.1i, and it will be fixed in the 6.1i software release.

Meanwhile, you can work around the issue by disabling Logical DRC checking during MAP as follows:

PCs:
set XIL_MAP_SKIP_LOGICAL_DRC=1

Workstations:
setenv XIL_MAP_SKIP_LOGICAL_DRC 1
AR# 15829
Date Created 10/10/2002
Last Updated 03/02/2006
Status Archive
Type General Article