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Author: Admin | 2025-04-28
To floorplan:standard cell row: The area allotted for the standard cells on the core is divided into rows where standard cells are placed. The height of the row is equal to the height of the standard cell and width varies. The height varies according to multiple standard cell row height. there may be double-height cells, triple-height cells, etc.The standard cells will sit in the row with proper orientation.fig: placement of standard cells in row fly lines: macros are placed manually using fly lines. fly lines are a virtual connection between macros and macros to IO pads. This helps the designer about the logical connection between macros and pads. Fly lines act as guidelines to the designer to reduce the interconnect length and routing resources.fly lines are of two types:macros to IO pin:macros to macros fly lines:halo(keep out margin): This is the region around the fixed macros so that no other macros and standard cell can be placed near to macros boundarythe width of the keep out margin on each side of the fixed cell can be the same or different depending on how you define keepout margin.keeping the placement of cells out of such regions avoids congestion and produce better qor.Halo of two adjacent macros can be overlap.If the macros moved from one place to another place, the halo will also move.ICC command for keepout margin:create_keepout_margin -outer {10 10 10 10} macro_name -type soft/hardcreate_keepout_margin -inner {10 10 10 10} macro_name -type soft/hardBlockages :Blockages are the specific location where the placing of cells is blocked.Blockages will not guide the tool but it allows not to place the standard cells buffer and inverters at some particular area i.e by using blockages we blocked the area so no standard cells and other cells won't be placed.If the macros moved from one place to another place, blockages will not move.Blockages are of three types. a) soft b) hard c)partialsoft blockages: only buffer can be placed. prevents from the placement of std cell and hard macro within the specified area during coarse placement but allows placement of buffer/inv during optimization, legalization and clock tree synthesis.create_placement_blockages -boundary {{10 20} {100 200}} -name PB1 -type softhard blockages:No standard cells, macros and buffer/inv can be placed within the specified area during coarse placement, optimization, and legalization.Used to avoid routing congestion at macros corners.Control power rails generation at the macros.create_placement_blockages -boundry {{10 20} {100 200}} -name PB1 -type hardpartial blockages: Partial blockages limit the cell density in the specified area. By default the blockage factor is 100% so no cells can be placed in that region but if we want to reduce density without blocking 100% area, we can change the blockage factor.create_placement_blockages -Boundry {10 20 100 200} -type
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