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AR# 8310

EXEMPLAR 1999.1g, MAP 2.1i: GSR is connected to GND, ERROR:OldMap:928 - There is no signal on pin A0 of CY4 symbol (sourceless)


Keyword: IFD, OFD, GSR, trim, sourceless

Urgency: Standard

General Description:
Customer instantiated STARTUP with a reset pin connected to GSR.
Some IFD and OFD are also instantiated.
The result, exemplar is connecting GSR of IFD and OFD to a common
GND which connects to other logic as follows:

(net (rename n394 "data_out(27)")
(portRef G (instanceRef i10 ))
(portRef GSR (instanceRef wait_ofd_a ))
(portRef GSR (instanceRef wait_ifd_b ))
(portRef A0 (instanceRef hdl_top_inst_dl_count_inst_modgen_gt_206_ix23 ))

Since GSR is connected to GND, map trim this out as well as net connected to A0 of
CY4. This result in map error:
ERROR:OldMap:928 - There is no signal on pin A0 of CY4 symbol
"dl_top_inst_dl_count_inst_modgen_gt_206_ix23" (output
signal=dl_top_inst_dl_count_inst_modgen_gt_206_nx21). Carry mode SUB-G-F1

Other possible effect is map trimming trailing logic connected to the same GND because it
is sourceless.

GSR/GTS pins on components should not be connected to other logic, unless it is GSR/GTS pin of
startup block.


Exemplar will fix this in future release.
Two workarounds are available:
Workaround #1:
Instead of instantiating IFD/OFD, instantiate IFD_NG and OFD_NG.

Workaround #2:
Add the following command after read and before optimize in your .tcl file as follows:
read $input_file_list
set_attribute -name FLOATVAL -value UNCONNECTED -port .xi4xl.OFD.NETLIST.GSR
set_attribute -name FLOATVAL -value UNCONNECTED -port .xi4xl.IFD.NETLIST.GSR
optimize -ta xi4xl

Note: Change xi4xl (4000xl library) to appropriate device library.
AR# 8310
Date Created 12/17/1999
Last Updated 08/28/2001
Status Archive
Type General Article