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Development System Reference Guide www.xilinx.com 113
R
Chapter 5
Logical Design Rule Check
This program is compatible with the following families:
• Virtex
™
, Virtex
™
-E
• Virtex
™
-II
• Virtex
™
-II Pro, Virtex
™
-II Pro X
• Virtex
™
-4
• Virtex
™
-5 LX
• Spartan
™
-II, Spartan
™
-IIE
• Spartan
™
-3, Spartan
™
-3E, Spartan
™
-3L
• CoolRunner
™
XPLA3, CoolRunner
™
-II
• XC9500
™
, XC9500XL
™
, XC9500XV
™
This chapter describes the Logical Design Rule Check (DRC). The chapter contains the
following sections:
• “Logical DRC Overview”
• “Logical DRC Checks”
Logical DRC Overview
The Logical Design Rule Check (DRC), also known as the NGD DRC, comprises a series of
tests to verify the logical design in the Native Generic Database (NGD) file. The Logical
DRC performs device-independent checks.
The Logical DRC generates messages to show the status of the tests performed. Messages
can be error messages (for conditions where the logic will not operate correctly) or
warnings (for conditions where the logic is incomplete).
The Logical DRC runs automatically at the following times:
• At the end of NGDBuild, before NGDBuild writes out the NGD file
NGDBuild writes out the NGD file if DRC warnings are discovered, but does not write
out an NGD file if DRC errors are discovered.
• At the end of NetGen, before writing out the netlist file
The netlist writer (NetGen) does not perform the entire DRC. It only performs the Net
checks and Name checks. The netlist writer writes out a netlist file even if DRC
warnings or errors are discovered.