Merge pull request #16 from embeddedci-com/worker-vocm-pd-pins

worker: VOCM and power-down pins are not supply pins

Author: wardviaene

CHANGELOG.md

@@ -17,6 +17,13 @@ The KiCad plugin is versioned and released separately; see
   estimate the Decoupling tab draws, 100 kHz to 1 GHz, computed in Go from the worker's
   branches and checked against the same fixture as the browser.
 
+### Fixed
+
+- Decoupling no longer treats a fully differential amplifier's VOCM input or an amplifier's
+  power-down pin (PD#, SHDN) as a supply pin when they sit on a net named like a rail. On the
+  BenchPod analog board the THS4551's VOCM on "2.05V" was reported as a supply with a 0.2 ohm
+  target.
+
 ## [0.4.0] - 2026-10-11
 
 ### Added

worker/emi_worker/rules/model.py

@@ -123,13 +123,15 @@ def net_activity(name: str) -> str:
     re.I,
 )
 #: Pin names that are clearly not a supply: GPIO port pins and the sense, control and status
-#: pins that sit on a supply-named net (a current monitor's IN+, a power mux's ST).
+#: pins that sit on a supply-named net (a current monitor's IN+, a power mux's ST, an
+#: amplifier's power-down PD# tied to its supply, a fully differential amplifier's VOCM input
+#: on a net named for its voltage, "2.05V").
 _SIGNAL_PIN = re.compile(
     r"^(?:p[a-k]\d+|pio\d*_?\d+|gpio\w*|io\w*|iob_\w+|[+-]?in[a-d]?[+-]|[+-]in[a-d]?|inp|inn|"
     r"s[+-]|s\d+[ab]?|d[ab]?|[+-]?out[a-d][+-]?|sense\w*|sns\w*|"
     r"fb|adj|n?en\w*|st|stat\w*|pr\d*|pg\w*|n?flt\w*|fault|alert|n?int\w*|irq|scl|sda|"
     r"ilim\w*|imon\w*|adc\w*|mode|sel\w*|n?cs\w*|set|n?rst\w*|reset\w*|mon\w*|det\w*|"
-    r"dvdt|ss|tr|nc|ctrl\w*)$",
+    r"dvdt|ss|tr|nc|ctrl\w*|v?ocm|n?pd#?|n?shdn\w*#?)$",
     re.I,
 )
 _SIGNAL_PIN_TYPES = frozenset({"input", "output", "bidirectional", "tri_state",

worker/tests/test_net_activity.py

@@ -64,6 +64,10 @@ def _p(function="", kind=""):
     ("D", "", False),
     ("OUTA", "", False),
     ("VS\u2013_5", "unspecified", True),  # THS4551 negative supply, with an en dash
+    ("VOCM_7", "unspecified", False),  # THS4551 output common-mode input on "2.05V"
+    ("PD#_3", "unspecified", False),   # THS4551 power-down, tied to its supply
+    ("SHDN", "", False),
+    ("PD3", "unspecified", False),     # still a GPIO, not a power-down
     ("V-", "", True),
     ("VREF", "input", True),           # a reference input needs its capacitor
     ("REF", "", True),