src/charger.cpp

@@ -383,13 +383,58 @@ void ChargerStateMachine()
          // VCU command is the primary exit. CheckUnplugged + CheckChargerFaults
          // remain for hardware safety; the self-decided CheckVoltage/CheckTimeout
          // exits are gone (S12 — VCU is authoritative).
+         //
+         // SKUDAK: ramp the DC-current reference toward zero across 3 ticks
+         // (300 ms) before transitioning to STOP. Without this, the VCU
+         // opening its HV contactor at the moment we go STOP triggers a hard
+         // 23 A → 0 disconnect transient that floods the Tesla BMS state-
+         // change CAN path and starves the VCU's task scheduler past its
+         // IWDG window (bench-confirmed 2026-05-21 limit-lower 0x002A loop).
+         // The VCU also defers its contactor open by ~1500 ms; together
+         // they make the disconnect graceful even on a hard limit-lower
+         // mid-RUN. completeRampTicks counts DOWN from 3 → 0; the original
+         // reference is stashed so if vcucmd reverts to Charging mid-ramp
+         // we restore cleanly.
+         static uint8_t completeRampTicks       = 0;
+         static s32fp   completeRampOriginalRef = 0;
          if (vcucmd == VCUCMD_COMPLETE)
          {
-            DigIo::acpres_out.Clear();
-            DigIo::evseact_out.Clear();
-            state = STOP;
+            if (completeRampTicks == 0)
+            {
+               completeRampOriginalRef = MIN(Param::Get(Param::idcspnt), Param::Get(Param::idclim));
+               completeRampTicks       = 3;
+            }
+            if (completeRampTicks > 1)
+            {
+               // Scale 2/3 → 1/3 → 0 across remaining ticks.
+               s32fp scaled = (completeRampOriginalRef * (completeRampTicks - 1)) / 3;
+               dcCurController.SetRef(scaled);
+               completeRampTicks--;
+               // Stay in EVSEACTIVATE this tick; current is decaying.
+            }
+            else
+            {
+               dcCurController.SetRef(0);
+               DigIo::acpres_out.Clear();
+               DigIo::evseact_out.Clear();
+               completeRampTicks       = 0;
+               completeRampOriginalRef = 0;
+               state                   = STOP;
+            }
+            break;
          }
-         else if (vcucmd == VCUCMD_STOPPED)
+
+         // vcucmd not Complete — if we were mid-ramp the user reversed
+         // (raised limit again); restore reference before the existing
+         // branches take over.
+         if (completeRampTicks != 0)
+         {
+            dcCurController.SetRef(completeRampOriginalRef);
+            completeRampTicks       = 0;
+            completeRampOriginalRef = 0;
+         }
+
+         if (vcucmd == VCUCMD_STOPPED)
          {
             // VCU revoked the charge command (e.g. user lowered limit below
             // current SOC but BMS isn't full yet). Park HV-armed in ENABLE