Connectivity Pattern Generation

Floorplanning of a grid-based design requires careful planning of the global signal, as it significantly affects the physical design decisions such as the channel spacing, pin placement, pin placement congestion etc. The utility classes provided here provide a sophisticated way to design global signal connectivity. We make assumptions that a design can be represented as a grid, and each index on the top level can be mapped to each (x,y) coordinate, as shown in the following figure.

Fig. 1 Base Grid

The connectivity pattern generated here creates a set of connection points (ConnectPointList) which indicates the top-level connections between top instances. For Example above figure shows that the global net is connected to the bottom port of the instance (3,1). The feedthrough from the instance (3,1) outputs signal to top output port, which is connected to the bottom input of the instance (3,2).

The grid allowed to (1,1) coordinate, any incoming/outgoing connection outside the grid is considered as a top-level connection.

Note

These classes only allow horizontal or vertical connection; a diagonal connection is not legal

ConnectionPattern

This is a primary grid that creates different connection patterns like H-tree structure, fish-bone structure, etc.

ConnectPointList

This class holds the list of connection points (ConnectPoint) and enables matrix operations like rotate, move_x, move_y, etc. Creating multiple ConnectPointList and merging them allows for more complex pattern creation.

ConnectPoint

This class stores the properties of the connection between two instances.

Examples:

Please refer exmaples section to learn more