The following are the Control Parameters during Floorplan
- Core Utilization
- Aspect ratio (H/W)
- Row/Core ratio
Width and Height:
- Row/Core ratio
Aspect Ratio (Ar):
Aspect ratio is the ratio between vertical routing resources to horizontal routing resources. If you specify a ratio of 1.00, the height and width are the same and therefore the core is a square. If you specify a ratio of 3.00, the height is three times the width.
Aspect Ratio(Ar) = Horizontal routing resource (H)/Vertical routing resource (V)
Core Utilization (Cu): It indicates the amount of core area used for cell placement. The number is calculated as a ratio of the total cell area (for hard macros and standard cells or soft macro cells) to the core area. A core utilization of 0.8, for example, means that 80% of the core area is used for cell placement and 20 percent is available for routing.
Core Utilization(Cu) = Standard Cell area/(Row area + Channel area)
Row to Core Ratio (Rcr): It indicates the amount of channel space to provide for routing between the cell rows. The smaller the number, the more space is left for routing. A value of 1.0 leaves no routing channel space.
Rcr = Row area / Core area (H x V)
Total utilization T(F) of floorplan F is derived using the following equation:
T(F) = (A(m) + A(p) + A(s) ) / A
- where A(m) = Area occupied by macros
- A(p) = Area occupied by Pads/ Pad fillers
- A(s) = Area occupied by Standard Cells
Cell row utilization C(F) of floorplan F is approximated using the following equation:
C(F) = A(s) / A(R -union(B, E, m, p))
- Where R= All cell rows
- B= All placement blockages
- E= Exclusive Regions