Steps of Floorplanning and its output

As we have seen in the previous post of Input Files and Macros Placement Guidelines for placing the macros. These guidelines lead our floorplan in the correct direction.

 

Floorplanning Steps

• Firstly, we have to create a library. 
• Import the design along with required files. 
• Ensure loading of SDC and, additional timing and power-related setups. 
• Decide the size and shape of block such are die area, core area. 
• Define voltage domains. 
• Placement of IO pins. 
• Standards must be outside the core area of block/design. 
• Macros should be placed using a data flow diagram and using Data Fly-lines also remember other placement guidelines. 
• Add Keepout Margin (Halo) around to Macros in order to avoid the overlapping. 
• Add physical only cells. Add placement and routing blockages.    

Caution for Floorplanning

At the first iteration of floorplanning, abutted the spacing between the macros. Then, present floorplan follows the regular process of powerplanning and timing checks, placement. At the placement stage, we have checks congestion in the design. From this congestion report, we will get an idea how much space we have to give between macros.

At the next iteration, we need to rearrange the macros along with spacing between macros. For spacing, we have to use the specific formula in order to give space:

Whereas,

Overflow = number of metal layer required though out the passage (Space between Macros)

Average pitch of metal = take average of the pitch of those metal which are overflowed

Total number of metals = number of metals overflowed

 

Output of Floorplanning

We will get floorplan of the design and we can generate floorplan DEF file. This DEF file can be used to improve the better-optimized netlist for placement to the synthesis team.

The process to get optimized netlist from the synthesis team for further PD steps is called Two Pass Synthesis.

At this note of discussion, we wrapped up this topic and we will meet soon with a new topic of Floorplan. Thank you. Have a nice day!!!