ICC2: Pre-placement readiness Cheat Sheet

This stage covers the gate before placement: legality of preplaced cells, dont-touch and cell-purpose scope, blockage and keepout review, tie and scan data readiness, and a congestion and timing check before the first placement run.

Sanity check cheat sheet

One row per command card. Read left to right: the check, the command that answers it, then what a healthy result, a result to review and a hard stop look like.

Card	Check and when	Command	Healthy	Review	Hard stop
R-01	Legality and cell inventory Before pre-placement setup	`check_legality` `report_cells`	Macros and preplaced physical cells match the floorplan record, and the legality check is clean on them.	Standard cells already placed, or fixed cells that no floorplan note explains.	A macro, end cap or tap that is unplaced or illegal.
R-02	Dont-touch and cell purpose After library and constraint setup	`report_dont_touch` `get_lib_cells -filter valid_purposes=~cts` `report_target_library_subset`	Every restricted object is one you listed, and cells that later steps need keep the right purpose.	Entries nobody listed, or a subset restriction that overrides a design-wide setting.	A cell that CTS or hold fixing needs is excluded with no recorded reason.
R-03	Blockages and keepout margins After floorplan, before placement	`get_placement_blockages`	Each blockage has a purpose, a type and a name, and region utilisation warnings in the log are understood.	Soft or partial blockages nobody recorded, which quietly remove open sites.	Utilisation above the project budget, or a hard blockage over an area the plan needs for cells.
R-04	Tie connections After physical cells, before placement	`connect_pg_net -tie` `add_tie_cells`	Tie pins are connected or deliberately left for the tie-cell step, and the plan says which.	Unconnected tie pins while tie insertion is planned after placement, which is expected but must be recorded.	Tie pins on a net that differs from the PG net of their cell.
R-05	Scan data After floorplan, before placement	`read_def <scandef>` `report_app_options`	SCANDEF is read for every scan block, and scan optimisation settings match the plan.	Scan optimisation switched off on purpose, or the missing-SCANDEF continue option set.	A scan block with no scan chain information, or scan settings that differ from the plan.
R-06	Placement and layer settings Before placement	`report_app_options` `report_ignored_layers`	Every non-default placement and optimisation option is in the pre-placement script with a stated reason.	An option set interactively that the script does not hold.	Congestion or scan settings that differ from the plan, or layer limits that differ from the routing plan.
R-07	Constraints and timing readiness Before placement	`check_timing` † `report_timing`	Constraint warnings are reviewed and the unplaced baseline slack is stored with its scenario list.	Negative slack before any wire exists, so placement starts with a deficit that needs an owner.	Constraint errors, or no constraints loaded, so placement would run without timing.
R-08	Congestion risk Before placement	`report_congestion` `report_ignored_layers`	Congestion on the floorplan alone is within the project budget, and narrow macro channels are recorded.	A hotspot in a macro channel, or a narrow channel with no plan for it.	A hotspot above the project budget that the floorplan, not placement, has to fix.
R-09	Ready-for-placement gate Last step before placement	`check_design` † `check_legality` `check_boundary_cells`	The design check reports no errors, and legality and boundary checks are clean on fixed objects.	Warnings that point to settings you made on purpose, each with a recorded reason.	Any design check error, or any violation on a macro or preplaced cell.

Command cheat sheet

ICC2 commands. Angle brackets are placeholders, and values shown are examples, not project limits. A dagger (†) marks a command the notes behind this book do not fully cover; it is shown without options, so confirm it with man or help in your release.

Legality and cell inventory
`check_legality`	Reports legality violations for the placed and fixed cells in the block.
`check_legality -cells $cells`	The same check limited to a collection of cells.
`report_cells`	Lists cells, to compare macro and physical-only cell counts with the floorplan record.
`check_boundary_cells`	Reports missing or wrong boundary cells before placement starts.
Dont-touch, size-only and cell purpose
`report_dont_touch`	Lists the dont_touch settings on modules, cells and nets.
`set_dont_touch [get_cells <inst>] true`	Excludes the cell from optimisation. Changes the session; record it.
`remove_attributes [get_cells <inst>] dont_touch`	Removes the setting again. Changes the session; record it.
`report_size_only -all`	Lists objects restricted to sizing only.
`set_lib_cell_purpose -exclude cts <lib_cells>`	Keeps the cells out of clock tree use. Persists in the block. Changes the session; record it.
`set_lib_cell_purpose -include cts <lib_cells>`	Allows the cells for CTS. A cell with dont_use is excluded from every purpose.
`get_lib_cells -filter valid_purposes=~cts`	The cells currently valid for CTS.
`report_target_library_subset`	The library subset restrictions now in force.
Blockages and keepout margins
`create_placement_blockage -boundary {{<x1> <y1>} {<x2> <y2>}} -type hard`	A hard blockage for cells and macros in the box. One call makes one blockage. Changes the session; record it.
`create_placement_blockage -boundary {{<x1> <y1>} {<x2> <y2>}} -type partial -blocked_percentage <pct>`	A density limit used in coarse placement only. Changes the session; record it.
`get_placement_blockages`	The blockages in the block, to compare with the floorplan record.
`remove_placement_blockages -all`	Removes every blockage. Changes the session; record it.
`create_keepout_margin -outer {<l> <b> <r> <t>} <macro>`	A hard keepout margin around the macro, in microns. Changes the session; record it.
Tie cells, scan and spares
`connect_pg_net -tie`	Connects tie-off pins only, without touching PG pins.
`add_tie_cells`	Inserts tie cells for tie pins. Run it once cells are placed and the plan allows it.
`read_def <scandef>`	Annotates scan chains from SCANDEF so placement can optimise them.
`set_app_options -name place.coarse.continue_on_missing_scandef -value true`	Lets placement continue for a block with no SCANDEF. Changes the session; record it.
`add_spare_cells -cell_name spare -lib_cell {<cell1> <cell2>} -num_instances <n>`	Adds the same count of each spare cell type, spread by cell density.
Settings and congestion
`report_app_options`	Lists application options, to record the settings behind the run.
`set_app_options -name place.coarse.handle_early_data -value true`	Lets placement continue when a region is over-utilised, for early floorplans. Changes the session; record it.
`report_congestion`	Congestion from the stored map, or from a map-only global route if none exists.
`report_ignored_layers`	Prints the layer limits used for estimation and congestion.
Readiness gate
`check_timing` †	Constraint consistency and completeness warnings.
`report_timing`	Timing paths before placement, as the baseline for the first placement run.
`check_design` †	The design prerequisite check before the placement stage.
`save_block -as <block>/<label>`	A labelled checkpoint to return to if placement is repeated. Writes to the library.