Answers Database

MAP M1.4.12: FATAL_ERROR:x4kma:x4kmaclkbuf.c:591:1.25 - No input sig on CLKBUF inst_name.


Record #3615

Product Family:  Software

Product Line:  FPGA Implementation

Problem Title:
MAP M1.4.12: FATAL_ERROR:x4kma:x4kmaclkbuf.c:591:1.25 - No input sig on
CLKBUF inst_name.



Problem Description:

Keywords: MAP, FATAL_ERROR, x4kma, xk4maclkbuf, CLKBUF, BUFG.

Urgency: Hot

General Description:

Targetting a 4000E or Spartan device with M1.4.12, MAP may
return with the following error message.

FATAL_ERROR:x4kma:x4kmaclkbuf.c:591:1.25 - No input sig on
CLKBUF inst_name.

This is known MAP issue that concerns driving a global buffer
with an internally-generated signal.

There will be a patch released soon to address this issue.  In
the meantime, please use the workaround below.
Also, this has been resolved in the the next release of M1.


Solution 1:

This problem is fixed in the latest M1.4 Core Tools Patch
available on the Xilinx Download Area:

ftp://ftp.xilinx.com/pub/swhelp/M1.4_alliance/core_sol14_m14.tar.Z
ftp://ftp.xilinx.com/pub/swhelp/M1.4_alliance/core_sun14_m14.tar.Z
ftp://ftp.xilinx.com/pub/swhelp/M1.4_alliance/core_hp14_m14.tar.Z
ftp://ftp.xilinx.com/pub/swhelp/M1.4_alliance/core_nt14.zip



Solution 2:


The workaround involves telling the tools not to trim out the
signal driving the global buffer.
This can be done by applying the "KEEP" attribute on the net
at the input of the BUFG.

In your schematic, apply an attribte name of "KEEP" on the net
leaving the value of the attribute blank.

Alternatively, this can be be done in a UCF file as follows.

 NET BUFG_SRC KEEP;

Please refer to the Libraries Guide more information on
attributes.



End of Record #3615