Chapter 12

Attributes, Constraints, and Carry Logic

This chapter lists and describes all the attributes that you can use with your design entry software and the constraints that are contained in machine- and user-generated files.

This chapter contains the following major sections.

• “Overview”
  
  
• “Information for Mentor Customers”
  
  
• “Schematic Syntax”
  
  
• “UCF/NCF File Syntax”
  
  
• “Attributes/Logical Constraints”
  
  This section contains alphabetical listings of the attributes and constraints as well as descriptions, syntax, and examples of each constraint.
  
  
• “Placement Constraints”
  
  
• “Relative Location (RLOC) Constraints”
  
  
• “Timing Constraints”
  
  
• “Physical Constraints”
  
  
• “Relationally Placed Macros (RPMs)”
  
  
• “Carry Logic in XC4000 and Spartans”
  
  
• “Carry Logic in XC5200”
  
  
• “Carry Logic in Virtex”