What is the use of keep-out margin around the macros?

Keepout Margin (Halo) It’s the region around the boundary of fixed macros in design in which no other macros or std-cells can be placed. It allows placement of buffers and inverters in its area.

Why pin placement is important in macro placement?

Placement should be done in proper multiple of tracks so that macros can be routed properly. 4. Avoid placement of Macros or stacks near the ports in order to avoid congestion in later stages of physical design. Placement of macros should happen in a way so that Macro pins face towards core to avoid detour.

What is the difference between keep-out margin and blockage?

Blockage: is given for various reasons. It means, no cell can occupy a particular region specified by the user. Difference: Keep-out margin is similar to blockage but it is given only in places where the problem prone cells are present. The tool identifies the cell’s location by itself and draws the blockage.

What is macro placement in VLSI?

Macros placement is done manually based on the connectivity with other macros and also with I/O pads. Flylines are used for placing macros manually. Fly/flight lines are virtual connections between macros and also macros to I/O pads.

What is keep out margin?

Keep-out margin: it is a region around the boundary of fixed cells in a block in which no other cells are placed. The width of the keep-out margin on each side of the fixed cell can be the same or different.

Why macros are placed preferably at boundary and not at Centre?

Place the macros around to the boundary of core, left some space between macro to core edge so that during optimization this space will be used for buffer/inverter insertion and keeping large area for placement of standard cell during placement stage.

Where should macros be placed?

Place the macro pins facing the core if the connectivity to the standard cells are higher. Group the Macros based on MBIST modules. Stack the macros based on routing blockages of the macros. If the technology is 14nm or below, take particular care of macro spacing.

What is macro placement?

Macro-cell placement is the problem of placing a given macro-cell circuit to optimize a certain objective (e.g., total wirelength). A macro- cell circuit usually contains a small number of macro-cells and a large number of standard-cells.

What is keep out margin in VLSI?

What is placement blockages in VLSI?

Placement blockages are the areas where placement of cells must be avoided in the defined region.

What are the goals of placement in VLSI?

Placement is the process of placing standard cells in the rows created at floorplanning stage. The goal is to minimize the total area and interconnects cost. The quality of routing is highly determined by the placement.