Xilinx Answer #6336 : 1.5i Virtex Map - ERROR:xvkma:125 - PAD encr_tx_clk.PAD does not have at least one IO buffer, possibly due to bad LOC constraint or missing buffer connection. i

Answers Database

1.5i Virtex Map - ERROR:xvkma:125 - PAD encr_tx_clk.PAD does not have at least one IO buffer, possibly due to bad LOC constraint or missing buffer connection. i

Record #6336
Problem Title:
1.5i Virtex Map - ERROR:xvkma:125 - PAD encr_tx_clk.PAD does not have at least one IO buffer, possibly due to bad LOC constraint or missing buffer connection. i

Problem Description:
URGENCY: Standard

General Description:

Map fails with the following error when -pr switch is used:

ERROR:xvkma:125 - PAD encr_tx_clk.PAD does not have at
least one IO buffer, possibly due to bad LOC constraint or missing
buffer connection.

Solution 1:

This error is related to use of the -pr switch (pack registers into IOBs)
in map. Some registers are being packed into IOBs in cases where the
pack is not legitimate.

The work around is to not use the -pr switch, but to control register
packing into IOBs with IOB attributs in the .ucf file.

This problem has been corrected for the 2.1i release due to begin
shipping in June.

Example UCF:

INST reg_on_problem_signal IOB=FALSE;
INST reg_to_be_put_in_IOB IOB=TRUE;

End of Record #6336 - Last Modified: 05/10/99 11:30

For the latest news, design tips, and patch information on the Xilinx design environment, check out the Technical Tips!