cf-precheck

ChipFoundry MPW tapeout precheck tool. Validates user projects before shuttle submission by running a sequence of design-rule and consistency checks.

Installation

pip install cf-precheck

External tool dependencies

Some checks invoke external EDA tools that must be available on $PATH:

KLayout — used by all Klayout DRC checks and the XOR check
Magic — used by the optional Magic DRC check and LVS
Netgen — used by the LVS check

Usage

cf-precheck -i <project_dir> -p <pdk_path> -c <caravel_root> [options] [check ...]

Required arguments

Flag	Description
`-i`, `--input-directory`	Path to the user project directory
`-p`, `--pdk-path`	Path to the PDK installation (variant-specific, e.g. `$PDK_ROOT/sky130A`)
`-c`, `--caravel-root`	Path to the golden Caravel root (or set `$GOLDEN_CARAVEL`)

Optional arguments

Flag	Description
`-o`, `--output-directory`	Output directory (default: `<project>/precheck_results/<timestamp>`)
`--magic-drc`	Include the Magic DRC check (off by default)
`--skip-checks check [...]`	Skip specific checks
`-v`, `--verbose`	Show verbose/debug output
`--version`	Print version and exit

Positional arguments

Pass one or more check names to run only those checks. If omitted, all applicable checks are run.

Example

# Run all checks
cf-precheck -i ./my_project -p $PDK_ROOT/sky130A -c ./caravel

# Run only specific checks
cf-precheck -i ./my_project -p $PDK_ROOT/sky130A -c ./caravel topcell_check gpio_defines

# Include the optional Magic DRC check
cf-precheck -i ./my_project -p $PDK_ROOT/sky130A -c ./caravel --magic-drc

# Skip certain checks
cf-precheck -i ./my_project -p $PDK_ROOT/sky130A -c ./caravel --skip-checks lvs oeb

Double-wide openframe

Double-wide projects are detected when exactly one of these GDS files is present:

gds/double_wide_openframe_project_wrapper.gds

Field	Value
Type	`double_wide`
User module	`double_wide_openframe_project_wrapper`
Top module	`double_wide_chip_io`
Golden wrapper	`double_wide_openframe_project_wrapper_empty`
User area	6754.63 × 4766.63 µm (59 GPIOs)

Pass the double-wide harness root (not stock Caravel) as -c. That root must provide:

gds/double_wide_openframe_project_wrapper_empty.gds
verilog/rtl/__double_wide_openframe_project_wrapper.v (port-list golden)

cf-precheck \
  -i ../dw_openframe_user_project \
  -p $PDK_ROOT/sky130A \
  -c ../dw_openframe

XOR uses erase_box_double_wide.tcl (scaled openframe perimeter erase). OEB uses the openframe CVC path with GPIO indices 0..58.

Checks

Check	Description
`topcell_check`	Validates the top cell name in the GDS
`gpio_defines`	Validates GPIO directives in `verilog/rtl/user_defines.v`
`pdn`	Power distribution network check
`metal_check`	Metal density check
`xor`	XOR comparison against the golden wrapper to detect out-of-bounds edits
`magic_drc`	Full DRC using Magic (optional, off by default)
`klayout_feol`	Klayout Front End Of Line DRC
`klayout_beol`	Klayout Back End Of Line DRC
`klayout_offgrid`	Klayout off-grid violations check
`klayout_metal_minimum_clear_area_density`	Klayout metal density check
`klayout_pin_label_purposes_overlapping_drawing`	Klayout pin/label overlap check
`klayout_zero_area`	Klayout zero-area cell check
`spike_check`	Detects invalid paths in the design
`illegal_cellname_check`	Detects cells with illegal names
`oeb`	Output-enable-bar signal connectivity check
`lvs`	Layout vs. Schematic check

Results

Check results are saved to <project>/.cf/project.json under the precheck key:

{
  "precheck": {
    "version": "1.0.0",
    "timestamp": "2026-03-17T12:00:00+00:00",
    "pdk": "sky130A",
    "passed": false,
    "checks": {
      "topcell_check": { "status": "pass", "duration_s": 1.2 },
      "gpio_defines": { "status": "fail", "duration_s": 0.8, "details": "..." }
    }
  }
}

Detailed logs are written to <project>/precheck_results/<timestamp>/logs/precheck.log.

License

Apache-2.0

Download files

Download the file for your platform. If you're not sure which to choose, learn more about installing packages.

Source Distribution

cf_precheck-1.3.6.tar.gz (3.6 MB view details)

Uploaded Aug 21, 2026 Source

Built Distribution

If you're not sure about the file name format, learn more about wheel file names.

The dropdown lists show the available interpreters, ABIs, and platforms. Enable javascript to be able to filter the list of wheel files.

cf_precheck-1.3.6-py3-none-any.whl (3.7 MB view details)

Uploaded Aug 21, 2026 Python 3

File details

Details for the file cf_precheck-1.3.6.tar.gz.

File metadata

Download URL: cf_precheck-1.3.6.tar.gz
Upload date: Aug 21, 2026
Size: 3.6 MB
Tags: Source
Uploaded using Trusted Publishing? Yes
Uploaded via: twine/7.0.0 CPython/3.13.14

File hashes

Hashes for cf_precheck-1.3.6.tar.gz
Algorithm	Hash digest
SHA256	`22748a7e22c2a31ca67dd949d765765b5fdbc07cdcf31215709131796ae37359`
MD5	`192c94e511a43af5a148d45155788da5`
BLAKE2b-256	`d373f494ac45354a794050b372aac21ad35b4ff72b6126bfc32ba58eb8b86342`

See more details on using hashes here.

Provenance

The following attestation bundles were made for cf_precheck-1.3.6.tar.gz:

Publisher: publish.yml on chipfoundry/cf-precheck

Attestations: Values shown here reflect the state when the release was signed and may no longer be current.

Statement:
- Statement type: https://in-toto.io/Statement/v1
- Predicate type: https://docs.pypi.org/attestations/publish/v1
- Subject name: cf_precheck-1.3.6.tar.gz
- Subject digest: 22748a7e22c2a31ca67dd949d765765b5fdbc07cdcf31215709131796ae37359
- Sigstore transparency entry: 2546475499
- Sigstore integration time: Aug 21, 2026
Source repository:
- Permalink: chipfoundry/cf-precheck@928f7af086faa9cb4138ef129a7db9d492b2f5f8
- Branch / Tag: refs/heads/main
- Owner: https://github.com/chipfoundry
- Access: public
Publication detail:
- Token Issuer: https://token.actions.githubusercontent.com
- Runner Environment: github-hosted
- Publication workflow: publish.yml@928f7af086faa9cb4138ef129a7db9d492b2f5f8
- Trigger Event: push