| commit | 426f95115110d6d0185f1ba3d09b3aa8a014969b | [log] [tgz] |
|---|---|---|
| author | R. Timothy Edwards <tim@opencircuitdesign.com> | Wed Sep 10 10:33:20 2025 -0400 |
| committer | R. Timothy Edwards <tim@opencircuitdesign.com> | Wed Sep 10 10:33:20 2025 -0400 |
| tree | e236f021088cc411835745d90b247339aeab57e3 | |
| parent | d12db87685f4c8859f9296f84e85a48707e249a0 [diff] |
Corrected an error in the GF library where an incorrect entry in the custom digital bidirectional I/O cell caused the liberty file for both the original GF library and the custom extension to be incorrect. Also: Updated the README file with more complete information, including information and instructions on GF180MCU, which had never been added; and comments about the IHP open PDK and about the "ciel" PDK package manager.
Summary:
Automatic setup of PDKs for open-source tools from foundry sources.
Builds out and populates a new set of directories and subdirectories in the open source format (started by Efabless), with the name for the PDK at the top, followed by categories “libs.ref” (IP) and “libs.tech” (EDA tool setup), each with subcategories corresponding to layout, abstract views, netlists, etc. for the IP; and magic, netgen, qflow, etc., for the EDA tool setup.
The populated PDK directories can contain either copies of files from the foundry sources, links to the foundry sources, or links back to another PDK.
Generates magic layout views for all vendor IP for which either a GDS view or a LEF view exists. Annotates the views as needed to handle ports, bounding boxes, etc.
This distribution contains sources for building out the SkyWater SKY130 130nm process and the GlobalFoundries GF180MCU process. Sources for the foundry process data are cloned automatically from repository services (primarily github).
Other non-free processes (such as X-Fab XH035 or XH018) can be obtained as “plug-ins” for open_pdks. Sources for non-free foundry process data must be obtained separately.
Read the README file in subdirectory sky130/ for instructions on building the SkyWater sky130A PDK, or in the directory gf180mcu/ for instructions on building the GlobalFoundries gf180MCU PDK.
License:
Open_PDKs is open-source software distributed under the Apache-2.0 license. See file LICENSE for the complete license text.
“Ciel” package manager:
An important consideration for anyone wishing to obtain one of the open source PDKs is that “open_pdks” is a PDK builder, and running it is like running a compiler to build a complex software application. Doing so can be difficult, time consuming, and resource-intensive. The software world came up with the idea of a “package manager” application that handles pre-built software. Likewise, there is a “PDK package manager” for handling pre-built PDKs, called “ciel” (formerly called “volare”), which can be found at https://github.com/fossi-foundation/ciel; However, “ciel” can be installed simply by doing:
pip install ciel
Most PDK end-users are likely to want this option. The “pip install” command will put “ciel” in /.local/bin/ciel where it may be necessary to either call it with the full path on the command line, or you may need to add "/.local/bin" to your PATH environment variable. Assuming it is in PATH, use the following commands:
ciel ls-pdks
returns a list of processes supported by ciel. To get a list of pre-built PDKs, use, e.g.,
ciel ls-remote --pdk-family=sky130
which lists PDKs by commit hash number. Then to install the PDK, use, e.g.,
ciel enable --pdk-family=sky130 <commit_hash>
The PDK will be installed into directory ~/.ciel/. Most open source EDA tools will be able to find the PDK if the environment variable “PDK_ROOT” is set to point to this location:
export PDK_ROOT=~/.ciel
for bash/sh environments, and
setenv PDK_ROOT ~/.ciel
for csh/tcsh environments.
Instructions:
git clone https://github.com/RTimothyEdwards/open_pdks.git cd open_pdks ./configure [options] make [sudo] make install
where the configure [options] are specific to each foundry PDK supported by open_pdks and can be queried using
./configure --help
At a minimum you will want to pass a configure option to declare the PDK that you want to build. It is possible to build multiple PDKs at once, but not recommended due to the large memory and disk space overhead required by each one.
./configure --enable-[PDK_name]-pdk
The open_pdks version of the PDK can be built locally within open_pdks without the need to declare an install target or run “make install”. However, it is highly recommended to declare a target location and install there, using
./configure --prefix=[path] --enable-[PDK_name]-pdk
followed by “make” and “make install”. The default install location is /usr/local/share/pdk ([path] above is /usr/local). The install location should be a read-only filesystem area for regular users, since the PDK contents should not be altered.
Also see the website at http://opencircuitdesign.com/open_pdks/. The “Install” page has full instructions for configuring and installing open_pdks.
Example usage:
SkyWater sky130 PDK: ./configure --prefix=/usr --enable-sky130-pdk --enable-sram-sky130 \ --enable-sram-space-sky130 --enable-reram-sky130 make sudo make install GlobalFoundries GF180MCU PDK: ./configure --prefix=/usr --enable-gf180mcu-pdk make sudo make install Both of these examples install into the directory /usr/share/pdk/. The first one builds PDKs sky130A (standard) and sky130B (with the ReRAM option). The second one builds PDKs gf180mcuA (3 metal stack), gf180mcuB (4 metal stack), gf180mcuC (5 metal stack with 0.9um thick top metal), and gf180mcuD (5 metal stack with 1.1um thick top metal). Existing shuttle services as of this writing (September 2025) use sky130A, sky130B (Cadence, Chip Foundry), and gf180mcuD (Wafer.Space). Given the configurations above with prefix "/usr", most open source tools will expect export PDK_ROOT=/usr/share/pdk (sh, bash) or setenv PDK_ROOT /usr/share/pdk (csh, tcsh)
A note about IHP SG13G2:
IHP GmbH released their open PDK for the SG13G2 process using the format described in open_pdks. For this reason, there is no need to use open_pdks to build the IHP open PDK, because it already comes pre-built, with full support for open source EDA tools. Also for this reason, the SG13G2 open PDK is supported by the "ciel" PDK package manager (see above).