UCF Articles - Boardor

Basics of Xilinx FPGA Constraints

2026-04-16 by boardor

1. Constraint Files There are three types of constraint files in Xilinx ISE FPGA design: User Constraint File (.UCF), Netlist Constraint File (.NCF), and Physical Constraint File (.PCF). These can achieve timing constraints, pin constraints, and area constraints. Users write UCF files during the design input phase, then the UCF file generates the NCF file … Read more

Introduction to Common Timing Constraints Based on ISE UCF Syntax

2026-04-12 by boardor

Timing constraints are the requirements and expectations we have for FPGA designs, for example, we hope the FPGA design can operate at what clock frequency, etc. Therefore, before the timing analysis tools begin to analyze our FPGA design, we must provide relevant timing constraint information. In the section on Timing Analysis Principles, we introduced many … Read more