The sky130 magic techfile splits nfet extraction on device width:
device msubcircuit sky130_fd_pr__nfet_01v8 nfet,scnfet ... w>=0.42
device msubcircuit sky130_fd_pr__special_nfet_01v8 scnfet ... w<0.42
ptx always emitted spice["nmos"], so every gate built from a
minimum-width device (drc["minwidth_tx"] = 0.36) was netlisted as
sky130_fd_pr__nfet_01v8 while magic extracted it as
sky130_fd_pr__special_nfet_01v8. netgen then reported a device class
mismatch in each such cell:
Circuit 1: sky130_fd_pr__special_nfet_01v8 (1) | Circuit 2: (no matching element)
Circuit 1: (no matching element) | Circuit 2: sky130_fd_pr__nfet_01v8 (1)
The signed-off macros shipped in sky130A/libs.ref/sky130_sram_macros use
special_nfet_01v8 at this geometry, so this restores the naming those
were built with.
ptx now asks the technology for a narrow-device model, keyed by width.
Technologies that declare no such model are unaffected, and there is no
equivalent split for pfets so only the nmos is declared.
After this change pinv and pinv_dec report "Netlists match uniquely"
where they previously mismatched. Verified with ngspice that
special_nfet_01v8 resolves through sky130.lib.spice, so characterization
is unaffected.
Co-Authored-By: Claude Opus 5 (1M context) <[email protected]>
Claude-Session: https://claude.ai/code/session_01FcKSuKSchDEd7MqT8AffpN
Must set PYTHONPATH to include OPENRAM_HOME now.
Reorganizes subdirs as packages.
Rewrites unit tests to use packages.
Update README.md with instructions, dependencies etc.
Update sky130 module imports.
Change tech specific package from modules to custom.
ThVerg
Eren Dogan
SWalker
Sage Walker
Eren Dogan
mrg