DISCLAIMER: The following sections are to give you an understanding of what happens under the hood in the Makefile.

Prerequisites

Magic VLSI Layout Tool is needed to run open_pdks -- version >= 8.3.60*

Setting up the PDK: skywater-pdk

Clone and build at least one skywater-pdk standard cell Library inside the pdks directory:

To setup one standard cell library only

    export PDK_ROOT=<absolute path to where skywater-pdk and open_pdks will reside>
    cd  $PDK_ROOT
    git clone https://github.com/google/skywater-pdk.git
    cd skywater-pdk
    git checkout 00bdbcf4a3aa922cc1f4a0d0cd8b80dbd73149d3
    git submodule update --init libraries/sky130_fd_sc_hd/latest
    git submodule update --init libraries/sky130_fd_sc_hvl/latest
    git submodule update --init libraries/sky130_fd_io/latest
    make timing

To setup other SCLs:
- replace sky130_fd_sc_hd with any of the following list:
  - sky130_fd_sc_hs
  - sky130_fd_sc_ms
  - sky130_fd_sc_ls
  - sky130_fd_sc_hdll

Setup the configurations and tech files for Magic, Netgen, OpenLane using open_pdks:

    cd $PDK_ROOT
    git clone git://opencircuitdesign.com/open_pdks
    cd open_pdks
    git checkout d8c159536699c9b4a08b650bddf791a9d48152f9
    ./configure --enable-sky130-pdk=$PDK_ROOT/skywater-pdk/libraries --with-sky130-local-path=$PDK_ROOT --enable-sram-sky130=disabled
    cd sky130
    make
    make install-local

Note: You can use different directories for sky130-source and local-path. However, in the instructions we are using $PDK_ROOT to facilitate the installation process

WARNING: Please, don't move sky130A from the installed directory because the generated .mag files contain absolute paths. Moving it will result in producing an invalid GDS.

To set the STD_CELL_LIBRARY (the default value is set to sky130_fd_sc_hd)
- Open configuration/general.tcl
- set STD_CELL_LIBRARY to one of the following:
```
  - sky130_fd_sc_hs
  - sky130_fd_sc_ms
  - sky130_fd_sc_ls
  - sky130_fd_sc_hdll
```

Refer to this for more details on the structure.