Skip to content

feat(sky130): preserve geometry-based MOS parameter in SKY130 #736

New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Open
rohanku wants to merge 2 commits into
base: main
Choose a base branch
from
Open

feat(sky130): preserve geometry-based MOS parameter in SKY130 #736

Show file tree
Hide file tree
Changes from all commits
Commits
Show all changes
2 commits
Select commit Hold shift + click to select a range
f7cfcb6
fix(sky130): preserve MOS parameters that Substrate does not model
rohanku Sep 10, 2026
fb50b38
fix(spectre): escape signal names in save and ic statements
rohanku Sep 17, 2026
File filter

Filter by extension

Filter by extension
Conversations
Failed to load comments.
Loading
Jump to
Jump to file
Failed to load files.
Loading
Diff view
Diff view
244 changes: 141 additions & 103 deletions pdks/sky130/src/lib.rs
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -113,6 +113,13 @@ pub enum Primitive {
kind: MosKind,
/// The MOSFET parameters.
params: MosParams,
/// Device parameters that Substrate does not model, preserved verbatim.
///
/// Populated when a MOSFET is imported from a SPICE netlist that sets parameters
/// beyond `w`, `l` and `nf` (junction areas and perimeters, stress parameters,
/// multiplicity, ...). Keys are lowercased, since SPICE parameter names are
/// case insensitive. Empty for MOSFETs that Substrate generates itself.
extra: HashMap<ArcStr, ParamValue>,
},
/// A precision resistor.
PrecisionResistor(PrecisionResistor),
Expand All @@ -135,6 +142,10 @@ impl scir::schema::Schema for Sky130 {
type Primitive = Primitive;
}

/// Parameters that [`MosParams`] models, and that therefore must not be duplicated in
/// [`Primitive::Mos::extra`].
const MOS_SIZING_PARAMS: [&str; 3] = ["w", "l", "nf"];

fn convert_spice_mos(
kind: &str,
params: &HashMap<UniCase<ArcStr>, ParamValue>,
Expand All @@ -145,55 +156,58 @@ fn convert_spice_mos(
Sky130Schema::Open | Sky130Schema::SrcNda => dec!(1e3),
Sky130Schema::Cds => dec!(1e9),
};
let mult = i64::try_from(
let numeric = |name: &'static str| {
params
.get(&UniCase::new(arcstr::literal!("mult")))
.get(&UniCase::new(ArcStr::from(name)))
.and_then(|expr| expr.get_numeric())
.copied()
.unwrap_or(dec!(1)),
)
.map_err(|_| ConvError::InvalidParameter)?;
let m = i64::try_from(
params
.get(&UniCase::new(arcstr::literal!("m")))
.and_then(|expr| expr.get_numeric())
.copied()
.unwrap_or(dec!(1)),
)
.map_err(|_| ConvError::InvalidParameter)?;
};
// `m` and `mult` are deliberately not folded into `nf`: the SKY130 models treat all
// three differently, so collapsing them changes the device. They are preserved in
// `extra` instead, which round-trips them back into the exported netlist.
let extra = params
.iter()
.filter(|(k, _)| !MOS_SIZING_PARAMS.contains(&k.to_lowercase().as_str()))
.map(|(k, v)| (ArcStr::from(k.to_lowercase()), v.clone()))
.collect();
Ok(Primitive::Mos {
kind,
params: MosParams {
w: i64::try_from(
*params
.get(&UniCase::new(arcstr::literal!("w")))
.and_then(|expr| expr.get_numeric())
.ok_or(ConvError::MissingParameter)?
* scale,
)
.map_err(|_| ConvError::InvalidParameter)?,
l: i64::try_from(
*params
.get(&UniCase::new(arcstr::literal!("l")))
.and_then(|expr| expr.get_numeric())
.ok_or(ConvError::MissingParameter)?
* scale,
)
.map_err(|_| ConvError::InvalidParameter)?,
nf: i64::try_from(
params
.get(&UniCase::new(arcstr::literal!("nf")))
.and_then(|expr| expr.get_numeric())
.copied()
.unwrap_or(dec!(1)),
)
.map_err(|_| ConvError::InvalidParameter)?
* m
* mult,
w: i64::try_from(numeric("w").ok_or(ConvError::MissingParameter)? * scale)
.map_err(|_| ConvError::InvalidParameter)?,
l: i64::try_from(numeric("l").ok_or(ConvError::MissingParameter)? * scale)
.map_err(|_| ConvError::InvalidParameter)?,
nf: i64::try_from(numeric("nf").unwrap_or(dec!(1)))
.map_err(|_| ConvError::InvalidParameter)?,
},
extra,
})
}

/// Combines the parameters Substrate derives from [`MosParams`] with those preserved
/// verbatim in [`Primitive::Mos::extra`].
///
/// A key present in both is multiplied rather than overwritten. Every key a schema derives
/// from [`MosParams`] that can also appear in `extra` (`mult` for the SRC NDA schema, `m`
/// and `mult` for the CDS schema) is a device multiplier, so the total is the product.
/// Parameters are returned sorted by name to keep netlists stable.
fn merge_mos_params(
sizing: impl IntoIterator<Item = (ArcStr, ParamValue)>,
extra: HashMap<ArcStr, ParamValue>,
) -> Vec<(ArcStr, ParamValue)> {
let mut merged: HashMap<ArcStr, ParamValue> = extra;
for (key, value) in sizing {
let combined = match (merged.get(&key).and_then(|v| v.get_numeric()), &value) {
(Some(existing), ParamValue::Numeric(derived)) => (existing * derived).into(),
_ => value,
};
merged.insert(key, combined);
}
let mut merged: Vec<_> = merged.into_iter().collect();
merged.sort_by(|(a, _), (b, _)| a.cmp(b));
merged
}

impl FromSchema<Spice> for Sky130 {
type Error = ConvError;

Expand Down Expand Up @@ -310,23 +324,24 @@ impl FromSchema<Sky130OpenSchema> for Spice {
.map(|(k, v)| (UniCase::new(k), v))
.collect(),
},
Primitive::Mos { kind, params } => spice::Primitive::RawInstance {
Primitive::Mos {
kind,
params,
extra,
} => spice::Primitive::RawInstance {
cell: kind.open_subckt(),
ports: vec!["D".into(), "G".into(), "S".into(), "B".into()],
params: HashMap::from_iter([
(
UniCase::new(arcstr::literal!("w")),
Decimal::new(params.w, 3).into(),
),
(
UniCase::new(arcstr::literal!("l")),
Decimal::new(params.l, 3).into(),
),
(
UniCase::new(arcstr::literal!("nf")),
Decimal::from(params.nf).into(),
),
]),
params: merge_mos_params(
[
(arcstr::literal!("w"), Decimal::new(params.w, 3).into()),
(arcstr::literal!("l"), Decimal::new(params.l, 3).into()),
(arcstr::literal!("nf"), Decimal::from(params.nf).into()),
],
extra,
)
.into_iter()
.map(|(k, v)| (UniCase::new(k), v))
.collect(),
},
_ => unimplemented!("unsupported primitive"),
})
Expand Down Expand Up @@ -373,14 +388,21 @@ impl FromSchema<Sky130OpenSchema> for Spectre {
ports,
params: params.into_iter().collect(),
},
Primitive::Mos { kind, params } => spectre::Primitive::RawInstance {
Primitive::Mos {
kind,
params,
extra,
} => spectre::Primitive::RawInstance {
cell: kind.open_subckt(),
ports: vec!["D".into(), "G".into(), "S".into(), "B".into()],
params: vec![
(arcstr::literal!("w"), Decimal::new(params.w, 3).into()),
(arcstr::literal!("l"), Decimal::new(params.l, 3).into()),
(arcstr::literal!("nf"), Decimal::from(params.nf).into()),
],
params: merge_mos_params(
[
(arcstr::literal!("w"), Decimal::new(params.w, 3).into()),
(arcstr::literal!("l"), Decimal::new(params.l, 3).into()),
(arcstr::literal!("nf"), Decimal::from(params.nf).into()),
],
extra,
),
},
_ => unimplemented!("unsupported primitive"),
})
Expand Down Expand Up @@ -453,23 +475,24 @@ impl FromSchema<Sky130SrcNdaSchema> for Spice {
.map(|(k, v)| (UniCase::new(k), v))
.collect(),
},
Primitive::Mos { kind, params } => spice::Primitive::Mos {
Primitive::Mos {
kind,
params,
extra,
} => spice::Primitive::Mos {
model: kind.src_nda_subckt(),
params: HashMap::from_iter([
(
UniCase::new(arcstr::literal!("w")),
Decimal::new(params.w, 3).into(),
),
(
UniCase::new(arcstr::literal!("l")),
Decimal::new(params.l, 3).into(),
),
(
params: merge_mos_params(
[
(arcstr::literal!("w"), Decimal::new(params.w, 3).into()),
(arcstr::literal!("l"), Decimal::new(params.l, 3).into()),
// Calibre decks don't support nf, so assign mult=nf instead.
UniCase::new(arcstr::literal!("mult")),
Decimal::from(params.nf).into(),
),
]),
(arcstr::literal!("mult"), Decimal::from(params.nf).into()),
],
extra,
)
.into_iter()
.map(|(k, v)| (UniCase::new(k), v))
.collect(),
},
Primitive::PrecisionResistor(res) => spice::Primitive::Res2 {
value: spice::ComponentValue::Model("mrp".into()),
Expand Down Expand Up @@ -516,14 +539,21 @@ impl FromSchema<Sky130SrcNdaSchema> for Spectre {
ports,
params: params.into_iter().collect(),
},
Primitive::Mos { kind, params } => spectre::Primitive::RawInstance {
Primitive::Mos {
kind,
params,
extra,
} => spectre::Primitive::RawInstance {
cell: kind.src_nda_subckt(),
ports: vec!["D".into(), "G".into(), "S".into(), "B".into()],
params: vec![
(arcstr::literal!("w"), Decimal::new(params.w, 3).into()),
(arcstr::literal!("l"), Decimal::new(params.l, 3).into()),
(arcstr::literal!("mult"), Decimal::from(params.nf).into()),
],
params: merge_mos_params(
[
(arcstr::literal!("w"), Decimal::new(params.w, 3).into()),
(arcstr::literal!("l"), Decimal::new(params.l, 3).into()),
(arcstr::literal!("mult"), Decimal::from(params.nf).into()),
],
extra,
),
},
Primitive::PrecisionResistor(res) => spectre::Primitive::RawInstance {
cell: "mrp".into(),
Expand Down Expand Up @@ -606,23 +636,24 @@ impl FromSchema<Sky130CdsSchema> for Spice {
.map(|(k, v)| (UniCase::new(k), v))
.collect(),
},
Primitive::Mos { kind, params } => spice::Primitive::Mos {
Primitive::Mos {
kind,
params,
extra,
} => spice::Primitive::Mos {
model: kind.cds_subckt(),
params: HashMap::from_iter([
(
UniCase::new(arcstr::literal!("w")),
Decimal::new(params.w, 9).into(),
),
(
UniCase::new(arcstr::literal!("l")),
Decimal::new(params.l, 9).into(),
),
(
UniCase::new(arcstr::literal!("m")),
Decimal::from(params.nf).into(),
),
(UniCase::new(arcstr::literal!("mult")), dec!(1).into()),
]),
params: merge_mos_params(
[
(arcstr::literal!("w"), Decimal::new(params.w, 9).into()),
(arcstr::literal!("l"), Decimal::new(params.l, 9).into()),
(arcstr::literal!("m"), Decimal::from(params.nf).into()),
(arcstr::literal!("mult"), dec!(1).into()),
],
extra,
)
.into_iter()
.map(|(k, v)| (UniCase::new(k), v))
.collect(),
},
_ => unimplemented!("unsupported primitive"),
})
Expand Down Expand Up @@ -650,14 +681,21 @@ impl FromSchema<Sky130CdsSchema> for Spectre {
ports,
params: params.into_iter().collect(),
},
Primitive::Mos { kind, params } => spectre::Primitive::RawInstance {
Primitive::Mos {
kind,
params,
extra,
} => spectre::Primitive::RawInstance {
cell: kind.cds_subckt(),
ports: vec!["D".into(), "G".into(), "S".into(), "B".into()],
params: vec![
(arcstr::literal!("w"), Decimal::new(params.w, 9).into()),
(arcstr::literal!("l"), Decimal::new(params.l, 9).into()),
(arcstr::literal!("m"), Decimal::from(params.nf).into()),
],
params: merge_mos_params(
[
(arcstr::literal!("w"), Decimal::new(params.w, 9).into()),
(arcstr::literal!("l"), Decimal::new(params.l, 9).into()),
(arcstr::literal!("m"), Decimal::from(params.nf).into()),
],
extra,
),
},
_ => unimplemented!("unsupported primitive"),
})
Expand Down
1 change: 1 addition & 0 deletions pdks/sky130/src/mos.rs
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -161,6 +161,7 @@ macro_rules! define_mosfets {
let mut prim = substrate::schematic::PrimitiveBinding::new(crate::Primitive::Mos {
kind: MosKind::$typ,
params: self.params.clone(),
extra: Default::default(),
});
prim.connect("D", io.d);
prim.connect("G", io.g);
Expand Down
Loading
Loading