Answers Database

GSR and GTS pads don't work in SXNF netlists from Synopsys for CPLDs.


Record #2866

Product Family:  Software

Product Line:  CPLD Implementation

Problem Title:
GSR and GTS pads don't work in SXNF netlists from Synopsys for CPLDs.


Problem Description:
Keywords: GSR, GTS, sxnf

Urgency: standard

General Desription:

Explicit global Set/Reset(GSR) or global tristate(GTS) input pads do
not work for CPLD designs if you use the Synopsys Design Compiler or
the FPGA Compiler to write out XNF(.sxnf) netlists.

The global pads are normally specified either by using the
set_pad_type -exact BUFGSR|BUFGTS dc shell command or by instantiating
BUFGSR/BUFGTS cells in place of IBUFs. These cells are erroneously
interpreted as global clock buffers(BUFG) during fitting and are
ignored.


Solution 1:

Use EDIF-formatted netlists (.sedif) for all Synopsys CPLD
designs in M1. All normal methods for specifying global buffers
work ok via EDIF.



End of Record #2866