User constraint file. UCF files are used to interact with Xilinx's implementation tools. UCF files are unique to Xilinx.
A format for feeding constraints and other controls into the Xilinx® ISE® tools.
One of the three types of constraint files in FPGA design, the user constraint file (.UCF). Full name: user constraint file. The remaining two are netlist constraint file (.NCF file) and physical constraint file (.PCF file). Used to complete timing constraints, pin constraints, and area constraints. The relationship of the three types of constraint files is: the user writes a UCF file during the design input phase, and then generates the NCF file after synthesizing the UCF file and the design, and finally generates the PCF file after being implemented. UCF files are ASCII code files that describe the constraints of logic design, and can be edited with a text editor and Xilinx constraint file editor.
FPGA Spartan-3A Family 50K Gates 1584 Cells 770MHz 90nm Technology 1.2V 100-Pin VTQFP
Spartan and Spartan-XL Families Field Programmable Gate Arrays
FPGA XC5200 Family 23K Gates 1936 Cells 83MHz 0.5um Technology 5V 240-Pin HSPQFP EP
FPGA Virtex-II Family 1M Gates 11520 Cells 650MHz 0.15um Technology 1.5V 575-Pin BGA
FPGA Spartan-3A Family 700K Gates 13248 Cells 667MHz 90nm Technology 1.2V 400-Pin FBGA