Chnages

csv_preprocessor.py

@@ -678,11 +678,12 @@ class LPMetrics:
         if self.flicker_suspect:
             if (self.hs_amplitude_mv is not None
                     and self.hs_amplitude_mv < HS_BURST_AMPLITUDE_MIN_MV
-                    and (self.lp_low_duration_ns is None
-                         or self.lp_low_duration_ns >= FLICKER_LP_LOW_MAX_NS)):
+                    and self.lp11_to_hs_ns is not None
+                    and self.lp11_to_hs_ns >= LP_LOW_DUR_MIN_NS):
                 lines.append(
                     f"  *** FLICKER SUSPECT: HS burst absent "
-                    f"(amplitude {self.hs_amplitude_mv:.0f} mV < {HS_BURST_AMPLITUDE_MIN_MV:.0f} mV) ***"
+                    f"(amplitude {self.hs_amplitude_mv:.0f} mV < {HS_BURST_AMPLITUDE_MIN_MV:.0f} mV, "
+                    f"lp11_to_hs={self.lp11_to_hs_ns:.0f} ns) ***"
                 )
             else:
                 lines.append(
@@ -851,12 +852,17 @@ def analyze_lp_file(path: Path) -> "LPMetrics":
     # check alone produces a false negative.
     #
     # Only flag DAT lane (CLK is continuous HS — LP states not expected).
-    # NOTE: lp11_to_hs_ns is NOT used here — on this hardware a consistent noise spike
-    # at LP-11 exit causes the rolling-std gate to fire at ~3 ns for every capture,
-    # making it indistinguishable from a genuine flicker (2.8 ns confirmed flicker).
+    # Guard: require lp11_to_hs_ns >= LP_LOW_DUR_MIN_NS to rule out the consistent
+    # ~3 ns noise spike at LP-11 exit.  On good captures the rolling-std gate fires
+    # at ~3 ns (hardware artifact); on confirmed flicker it fires at ~347 ns (real
+    # LP-low completes, then HS never starts → bridge returns to LP-11).
+    # Without this guard, DC-like HS data (uniform display content) produces low
+    # amplitude on otherwise good captures and causes false positives.
     hs_burst_absent = (
         hs_amplitude_mv is not None
         and hs_amplitude_mv < HS_BURST_AMPLITUDE_MIN_MV
+        and lp11_to_hs_ns is not None
+        and lp11_to_hs_ns >= LP_LOW_DUR_MIN_NS
     )
     flicker_suspect = (
         channel == "dat"