Intel® Quartus® Prime Standard Edition User Guide: Design Compilation

ID 683283
Date 9/24/2018
Document Table of Contents

2.8.1. The Difference between Logical Partitions and Physical Regions

Design partitions are logical entities based on the design hierarchy. LogicLock regions are physical placement assignments that constrain logic to a particular region on the device.

A common misconception is that logic from a design partition is always grouped together on the device when you use incremental compilation. Actually, logic from a partition can be placed anywhere in the device if it is not constrained to a LogicLock region, although the Fitter can pack related logic together to improve timing performance. A logical design partition does not refer to any physical area on the device and does not directly control where instances are placed on the device.

If you want to control the placement of logic from a design partition and isolate it to a particular part of the device, you can assign the logical design partition to a physical region in the device floorplan with a LogicLock region assignment. Altera recommends creating a design floorplan by assigning design partitions to LogicLock regions to improve the quality of results and avoid placement conflicts in some situations for incremental compilation.

Another misconception is that LogicLock assignments are used to preserve placement results for incremental compilation. Actually, LogicLock regions only constrain logic to a physical region on the device. Incremental compilation does not use LogicLock assignments or any location assignments to preserve the placement results; it simply reuses the results stored in the database netlist from a previous compilation.