Chnages

csv_preprocessor.py

@@ -65,6 +65,15 @@ CLK_LP_LOW_MIN_NS = 300.0
 HS_BURST_AMPLITUDE_MIN_MV = 40.0  # mV — below this, no real HS burst is present
 #   Lowered from 50 mV: 48 mV capture (0001) was a false alarm; true flicker (0008) at 34 mV.
 
+# HS oscillation fraction thresholds.
+# Measures fraction of post-LP-low window (100 ns margin, 3 µs look-ahead) where rolling_std
+# exceeds HS_OSC_STD_V.  With dynamic video at 432 Mbps DDR each bit spans ~4.6 ns; transitions
+# (~1 ns) fire the 1 ns rolling window ~20% of the time → healthy HS → osc_frac ≈ 0.14–0.22.
+# Blanking/control packets carry uniform data → osc_frac ≈ 0.00–0.02 (confirmed NOT flicker).
+# Partial or transient HS dropout sits between these bands → suspicious → send to Claude.
+HS_OSC_FRACTION_SUSPICIOUS_LO = 0.04   # below this: dead HS — blanking / control (normal)
+HS_OSC_FRACTION_SUSPICIOUS_HI = 0.13   # above this: healthy HS; between bands → flag
+
 
 # Mode A minimum amplitude: LP-11-return edge artifacts produce near-zero amplitude in the
 # burst window (burst is pure LP-low DC between two LP-11 regions).  Require ≥ this to
@@ -754,6 +763,7 @@ class LPMetrics:
     # A capture is flagged when the LP-low plateau is absent or shorter than
     # FLICKER_LP_LOW_MAX_NS.  Normal captures show ~340 ns; flicker shows 0–50 ns.
     hs_rolling_std_found: bool = False  # rolling-std fired in HS window after LP-low ended
+    hs_osc_fraction: Optional[float] = None  # fraction of post-LP-low window (100 ns margin, 3 µs) where rolling_std ≥ HS_OSC_STD_V
     flicker_suspect: bool = False
 
     warnings: list = field(default_factory=list)
@@ -894,6 +904,7 @@ def analyze_lp_file(path: Path) -> "LPMetrics":
     hs_burst_dur_ns  = None
     hs_amplitude_mv  = None
     hs_rolling_std_found = False
+    hs_osc_fraction = None
     s_end = None
     rstd  = None
 
@@ -949,8 +960,6 @@ def analyze_lp_file(path: Path) -> "LPMetrics":
                 )
 
         # Did rolling-std fire in the actual HS window (after LP-low ended)?
-        # With dynamic display content (video), genuine HS keeps rolling-std above
-        # threshold; absent HS does not.  Used to gate Mode B/D false positives.
         if lp_low_duration_ns is not None:
             lp_low_end_idx = s_end + int((lp_low_duration_ns + 50.0) * 1e-9 / dt)
             hs_check_end   = min(lp_low_end_idx + int(1000e-9 / dt), len(rstd))
@@ -958,6 +967,14 @@ def analyze_lp_file(path: Path) -> "LPMetrics":
                 hs_rolling_std_found = bool(
                     np.any(rstd[lp_low_end_idx:hs_check_end] >= HS_OSC_STD_V)
                 )
+            # hs_osc_fraction: 100 ns margin past LP-low end, look ahead 3 µs
+            # (lp_low_end_idx already includes 50 ns; add 50 ns more = 100 ns total)
+            hs_osc_start = lp_low_end_idx + int(50e-9 / dt)
+            hs_osc_end   = min(hs_osc_start + int(3000e-9 / dt), len(rstd))
+            if hs_osc_end - hs_osc_start >= int(500e-9 / dt):
+                hs_osc_fraction = round(
+                    float(np.mean(rstd[hs_osc_start:hs_osc_end] >= HS_OSC_STD_V)), 4
+                )
 
     # ── Warnings ─────────────────────────────────────────────────────────
     warnings = []
@@ -994,7 +1011,7 @@ def analyze_lp_file(path: Path) -> "LPMetrics":
                 f"(TCLK_PREPARE+TCLK_ZERO minimum) — SN65DSI83 may fail to lock CLK lane"
             )
 
-    # Flicker suspect: three confirmed failure modes on this hardware:
+    # Flicker suspect: confirmed failure modes on this hardware:
     #
     #   A) Normal LP-low (~342–380 ns) → bridge misses SoT → returns to LP-11
     #      Signature: lp11_to_hs fires at real LP-low end (~347 ns), hs_amplitude ≈ 15–30 mV.
@@ -1005,18 +1022,18 @@ def analyze_lp_file(path: Path) -> "LPMetrics":
     #      Signature: lp11_to_hs is None (rolling-std < HS_OSC_STD_V throughout 500 ns
     #      lookahead), hs_amplitude < 50 mV, LP-11 returns ~500 ns later.
     #
-    #   B) Short LP-low (< 200 ns, vs nominal ~342–380 ns) → anomalous SoT timing.
+    #   B) (removed — short-LP-low flicker is now caught by Mode F if osc_frac is in the
-    #      Flag on LP-low duration alone: any lp_low < 200 ns is outside the normal range
+    #      suspicious zone; Mode B was causing false positives on blanking packets which
-    #      and warrants investigation regardless of amplitude or rolling-std state.
+    #      legitimately have short LP-low and low amplitude due to uniform DC HS data)
-    #      Confirmed: capture 0124 (lp_low=108 ns).
     #
     #   C) No LP-11 detected at all → MIPI link silent or stuck.
     #
+    #   F) Normal LP-low but partial/transient HS dropout: hs_osc_fraction in suspicious zone
+    #      (HS_OSC_FRACTION_SUSPICIOUS_LO < osc_frac < HS_OSC_FRACTION_SUSPICIOUS_HI).
+    #      Healthy HS: ~0.14–0.22.  Blanking/control (normal): ~0.00–0.02.  Dropout: 0.04–0.13.
+    #      Confirmed: capture 0105 Apr-23 run (osc_frac=0.079, lp_low=380 ns).
+    #
     # Only flag DAT lane (CLK is continuous HS — LP states not expected).
-    _lp_low_short = (
-        lp_low_duration_ns is not None
-        and lp_low_duration_ns < 200.0   # below this, LP-low is anomalously brief
-    )
     hs_burst_absent = (
         hs_amplitude_mv is not None
         and hs_amplitude_mv < HS_BURST_AMPLITUDE_MIN_MV
@@ -1035,8 +1052,6 @@ def analyze_lp_file(path: Path) -> "LPMetrics":
             # Mode A2: rolling-std never fired — HS absent or amplitude below HS_OSC_STD_V;
             # weak oscillations are misclassified as LP-low, masking the true HS failure
             or lp11_to_hs_ns is None
-            # Mode B: LP-low anomalously short + low amplitude = marginal HS launch.
-            or _lp_low_short
         )
     )
     # Mode C: no LP-11 at all → link silent (but exclude CLK which is always HS)
@@ -1045,6 +1060,12 @@ def analyze_lp_file(path: Path) -> "LPMetrics":
         and not continuous_hs_clk
         and not lp11_regions
     )
+    mode_f_partial_hs = (
+        lp_transition_valid
+        and lp_low_duration_ns is not None
+        and hs_osc_fraction is not None
+        and HS_OSC_FRACTION_SUSPICIOUS_LO < hs_osc_fraction < HS_OSC_FRACTION_SUSPICIOUS_HI
+    )
     flicker_suspect = (
         channel == "dat"
         and (
@@ -1054,7 +1075,7 @@ def analyze_lp_file(path: Path) -> "LPMetrics":
                 and (
                     lp_low_duration_ns is None
                     or hs_burst_absent
-                    or _lp_low_short
+                    or mode_f_partial_hs
                 )
             )
         )
@@ -1077,6 +1098,7 @@ def analyze_lp_file(path: Path) -> "LPMetrics":
         lp_transition_valid  = lp_transition_valid,
         clk_lp_startup_ok    = clk_lp_startup_ok,
         hs_rolling_std_found = hs_rolling_std_found,
+        hs_osc_fraction      = hs_osc_fraction,
         flicker_suspect      = flicker_suspect,
         warnings             = warnings,
     )