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AR# 21217

7.1i XST - "WARNING:Xst:1780 - Signal <JTAG_*> is never used or assigned."

Description

Keywords: JTAG, UniSim, GSR

When I declare signals and then do not use them, XST generates the following warning message:

"WARNING:Xst:1780 - Signal <signal_name> is never used or assigned."

Solution

1

To clear the warning message, remove the signal declaration from the HDL code.

This has been fixed with the release of ISE 9.1i.

2

If all declared signals are being used and you are using the UniSim library, you will receive the following warning messages:

WARNING:Xst:1780 - Signal <JTAG_CAPTURE_GLBL> is never used or assigned.
WARNING:Xst:1780 - Signal <JTAG_USER_TDO3_GLBL> is never used or assigned.
WARNING:Xst:1780 - Signal <JTAG_RESET_GLBL> is never used or assigned.
WARNING:Xst:1780 - Signal <JTAG_TDO_GLBL> is never used or assigned.
WARNING:Xst:1780 - Signal <JTAG_SEL1_GLBL> is never used or assigned.
WARNING:Xst:1780 - Signal <JTAG_USER_TDO4_GLBL> is never used or assigned.
WARNING:Xst:1780 - Signal <JTAG_SEL2_GLBL> is never used or assigned.
WARNING:Xst:1780 - Signal <JTAG_TCK_GLBL> is never used or assigned.
WARNING:Xst:1780 - Signal <JTAG_TMS_GLBL> is never used or assigned.
WARNING:Xst:1780 - Signal <JTAG_SEL3_GLBL> is never used or assigned.
WARNING:Xst:1780 - Signal <JTAG_USER_TDO1_GLBL> is never used or assigned.
WARNING:Xst:1780 - Signal <GSR> is never used or assigned.
WARNING:Xst:1780 - Signal <JTAG_SEL4_GLBL> is never used or assigned.
WARNING:Xst:1780 - Signal <JTAG_UPDATE_GLBL> is never used or assigned.
WARNING:Xst:1780 - Signal <JTAG_SHIFT_GLBL> is never used or assigned.
WARNING:Xst:1780 - Signal <JTAG_USER_TDO2_GLBL> is never used or assigned.
WARNING:Xst:1780 - Signal <JTAG_TRST_GLBL> is never used or assigned.
WARNING:Xst:1780 - Signal <JTAG_TDI_GLBL> is never used or assigned

The above warning messages can be ignored.
AR# 21217
Date Created 04/13/2005
Last Updated 01/07/2009
Status Archive
Type General Article