Constraint File Formats

For new CPLD and ispXPGA projects, the ispLEVER software creates a temporary constraint file (.lct), which is a working copy of the project constraint file (.lci) and used to specify constraints such as location and path delay information in a textual form. The ispLEVER software uses the LCT file when placing and routing the design. When you save the design (File > Save), the contents of the LCT file are saved to the LCI file.

ORCA/EC/ECP/XP devices use a preference file (.prf), which contains preferences (placement, routing, and/or timing constraints) specified during design entry and preferences added by the user. The PRF file is an optional input to the MAP, PAR, EPIC, and TRACE processes.