4.3. Place-and-Route

Hammer has an action for placing and routing a synthesized design. This action requires a tool plugin to implement HammerPlaceAndRouteTool.

4.3.1. P&R Setup Keys

  • Namespace: vlsi.core

    • par_tool_path

      • Set to the directory containing the tool plugin directory for the place-and-route tool, typically /path/to/tool_plugin/par. This will be the parent directory of the directory containing __init__.py and defaults.yml.
    • par_tool

      • Actual name of the P&R tool that is setup in the directory, par_tool_path, e.g. innovus

4.3.2. P&R Input Keys

  • Namespace: vlsi

    • These are built-in Hammer APIs covered in Hammer APIs
  • Namespace: par

    • inputs.input_files ([])

      • List of paths to post-synthesis netlists. Auto-populated after syn-to-par.
    • inputs.top_module (str)

      • Name of top RTL module to P&R. Auto-populated after syn-to-par.
    • inputs.post_synth_sdc (str)

      • Post-synthesis generated SDC. Auto-populated after syn-to-par.
    • inputs.gds_map_mode (str)

      • Specify which GDS layermap file to use. auto uses the technology-supplied file, whereas manual requires a file to specified via inputs.gds_map_file.
    • inputs.gds_merge (bool)

      • True tells the P&R tool to merge all library & macro GDS before streamout. Otherwise, only references will exist and merging needs to be done later, by a tool such as Calibre, gdstk, or gdspy.
    • inputs.physical_only_cells_mode (str)

      • Specifies which set of cells to exclude from SPICE netlist because they have no logical function. auto uses the technology-supplied list, whereas manual and append overrides and appends to the supplied list, respectively.
    • submit (dict)

      • Can override global settings for submitting jobs to a workload management platform.
    • power_straps_mode (str)

      • Power straps configuration. generate enables Hammer’s power straps API, whereas manual requires a TCL script in power_straps_script_contents.
    • blockage_spacing (Decimal)

      • Global obstruction around every hierarchical sub-block and hard macro
    • generate_power_straps_options (dict)

      • If generate_power_straps_method is by_tracks, this struct specifies all the options for the power straps API. See Hammer APIs for more detail.

4.3.3. P&R Inputs

There are no other prerequisites to running place & route other than setting the keys described above.

4.3.4. P&R Outputs

  • Hierarchical (e.g. Cadence ILMs) and between-step snapshot databases in OBJ_DIR/par-rundir
  • GDSII file with final design: {OBJ_DIR}/par-rundir/{TOP_MODULE}.gds
  • Verilog gate-level netlist: {OBJ_DIR}/par-rundir/{TOP_MODULE}.lvs.v
  • SDF file for post-par simulation: {OBJ_DIR}/par-rundir/{TOP_MODULE}.sdf
  • Timing reports: {OBJ_DIR}/par-rundir/timingReports
  • A script to open the final chip: {OBJ_DIR}/par-rundir/generated_scripts/open_chip

P&R output Hammer IR {OBJ_DIR}/par-rundir/par-output.json is converted to inputs for the DRC, LVS, and simulation tools by the par-to-drc, par-to-lvs, and par-to-sim actions, respectively.

4.3.5. P&R Commands

  • P&R Command (after syn-to-par is run)

    • hammer-vlsi -e env.yml -p {OBJ_DIR}/par-input.json --obj_dir OBJ_DIR par
  • P&R to DRC

    • hammer-vlsi -e env.yml -p config.yml -p {OBJ_DIR}/par-rundir/par-output.json --obj_dir OBJ_DIR par-to-drc
  • P&R to LVS

    • hammer-vlsi -e env.yml -p config.yml -p {OBJ_DIR}/par-rundir/par-output.json --obj_dir OBJ_DIR par-to-lvs
  • P&R to Simulation

    • hammer-vlsi -e env.yml -p config.yml -p {OBJ_DIR}/par-rundir/par-output.json --obj_dir OBJ_DIR par-to-sim