fix: restore PI reference on final ramp tick (iteration O regression)

The iteration O 3-tick ramp ended with dcCurController.SetRef(0) before
transitioning to STOP. Param::Change only fires when idcspnt or idclim
parameter values change — a normal STOP → OFF → WAITSTART → ENABLE →
ACTIVATE → RUN → EVSEACTIVATE restart cycle never touches those, so
nothing restored the PI reference. On the next entry to EVSEACTIVATE
the controller targeted 0 A and the charger sipped ~0.1 kW.

Bench-confirmed 2026-05-21 on iteration O firmware: after lowering the
ChargeLimit_pct to drop into COMPLETE and then raising it back, charging
restarted at 0.1 kW instead of ramping to 9 kW.

Fix: on the final ramp tick, restore SetRef to MIN(idcspnt, idclim)
instead of zeroing it. The GPIO clears (acpres_out, evseact_out) still
cut AC enable so the output current decays through the filter caps;
the reference value is irrelevant during STOP but matters for the next
EVSEACTIVATE entry.

The ramp-restore block in the vcucmd != Complete branch (charger.cpp:431
in iteration O) only handles the mid-ramp reversal case (counter ≠ 0);
it didn't help when the ramp completed cleanly. This commit closes that
gap.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

include/param_prj.h

@@ -47,7 +47,7 @@
    3. Display values
  */
 //Next param id (increase when adding new parameter!): 24
-//Next value Id: 2052
+//Next value Id: 2053
 /*              category     name         unit       min     max     default id */
 #define PARAM_LIST \
     PARAM_ENTRY(CAT_CHARGER, idclim,      "A",       0,      45,     45,     3   ) \
@@ -109,6 +109,7 @@
     VALUE_ENTRY(c3udc,       "V",     2035 ) \
     VALUE_ENTRY(c3idc,       "A",     2036 ) \
     VALUE_ENTRY(tmpobcmax,   "°C",    2051 ) \
+    VALUE_ENTRY(vcucmd,      VCUCMDS, 2052 ) \
     VALUE_ENTRY(test_time,   "s",     3000 ) \
     VALUE_ENTRY(test_timer_flag,   "X",     3001 ) \
     VALUE_ENTRY(test_timer_icvalue,   "X",     3002 ) \
@@ -118,6 +119,12 @@
 #define OPMODES      "0=Off, 1=Run"
 #define CHARGERS     "1=Charger1, 2=Charger2, 4=Charger3"
 #define OFFON        "0=Off, 1=On"
+// SKUDAK-S12: VCU→charger control command on 0x212 byte 3. Mirrors the Dilong
+// path's OBC_ControlCMD vocabulary exactly so VCU code paths can be reused.
+//   0 = Charging — VCU wants current to flow; walk to / hold at EVSEACTIVATE
+//   1 = Stopped  — VCU is not driving a cycle; sit in OFF/WAITSTART/ENABLE
+//   2 = Complete — VCU has terminated the cycle; drop to STOP
+#define VCUCMDS      "0=Charging, 1=Stopped, 2=Complete"
 #define CHFLAGS      "0=None, 1=Enabled, 2=Fault, 4=CheckAlive"
 #define STATES       "0=Off, 1=WaitStart, 2=Enable, 3=Activate, 4=Run, 5=Stop"
 #define INPUTS       "0=Type2, 1=Type2-3P, 2=Type1, 3=Manual, 4=Manual-3P, 5=Type2-Auto"
@@ -129,7 +136,39 @@
 // SKUDAK customization suffix: bump on every Skudak-side change so the OpenInverter
 // web UI shows a distinct version (e.g. "4=1.20.R-S4") and we can visually confirm
 // the right firmware is flashed. Match the stm32-sine -S<N> convention.
-#define VERSTR STRINGIFY(4=VER-S5)
+// -S6 was withdrawn (PR #8 closed): the canary-rebuild attempt called
+// canMap->Clear() inside MapChargerMessages, which recursed through the
+// HandleClear callback and stack-overflowed at boot before the terminal
+// came up. Jumping straight to -S7 so any bench that still reports -S6
+// in the openinverter UI is visibly the broken build and gets re-flashed.
+// -S8 trims chargercan.cpp from 73 → 37 entries so the libopeninv 50-slot
+// pool doesn't silently drop the SKUDAK 0x211 broadcast on rebuild.
+// -S9 restores 8 c2/c3 RX entries (uac/flag/idc/udc per module). -S8 over-
+// trimmed multi-module Tesla OBC support: CalcTotals was summing only
+// module 1's contribution, so reported pack power was 1/3 of actual delivery.
+// -S10 added udclim RX on 0x212 bytes 1-2. The VCU sent udclim=200V to force
+// CheckVoltage() to fire (udc > udclim → STOP). DEPRECATED in -S11: the
+// per-module DC voltage readings (c1udc/c2udc/c3udc) collapse below 200V
+// once VCU opens HV contactors, so the trigger never accumulates 10 ticks.
+// udclim RX is kept mapped but the VCU now always sends 398V (no-op).
+//
+// -S11 adds vcustop RX on 0x212 byte 3 — an explicit VCU command lever that
+// mirrors the Dilong path's OBC_ControlCMD. When VCU enters CHARGE_COMPLETE
+// it sets vcustop=1; ChargerStateMachine's EVSEACTIVATE case transitions to
+// STOP immediately, the J1772 CP signal drops, EVSE stops delivering AC,
+// VCU_IsCharging() returns 0, water pumps power down naturally.
+// -S12 promotes byte 3 from a binary vcustop flag to the full 3-state
+// VCUCMDS vocabulary (0=Charging, 1=Stopped, 2=Complete), matching the
+// Dilong OBC_ControlCMD exactly. The internal FSM now obeys vcucmd for
+// lifecycle transitions: ENABLE only advances to ACTIVATE on Charging, STOP
+// returns to OFF when vcucmd flips back to Charging/Stopped (fixes the
+// "raise ChargeLimit mid-COMPLETE doesn't resume" wedge — teslacharger was
+// stuck in STOP because STOP only exited on CheckUnplugged). The self-
+// decided EVSEACTIVATE exits (CheckVoltage, CheckTimeout) are stripped; the
+// VCU is now authoritative for when charging starts and stops. The charger
+// retains hardware-level wisdom: CheckUnplugged() still forces OFF from any
+// state, and CheckStartCondition() still gates OFF→WAITSTART on EVSE pilot.
+#define VERSTR STRINGIFY(4=VER-S12)
 
 /***** enums ******/
 
@@ -153,6 +192,18 @@ enum states
    STOP
 };
 
+// SKUDAK-S12: VCU→charger command vocabulary on 0x212 byte 3. Must match
+// the values exposed via VCUCMDS enum string AND the VCU's
+// VCU_OIOBCCommand_t enum (stm32-hal-vcu Core/Inc/applications/charger/
+// charger_types.h). Updating one without the others silently breaks the
+// charge state machine, so keep them in lock-step.
+enum vcucmds
+{
+   VCUCMD_CHARGING = 0,
+   VCUCMD_STOPPED  = 1,
+   VCUCMD_COMPLETE = 2
+};
+
 enum _canspeeds
 {
    CAN_PERIOD_100MS = 0,

src/charger.cpp

@@ -299,10 +299,26 @@ void CalcAcCurrentLimit()
    Param::SetFloat(Param::aclim, iacLim);
 }
 
+// SKUDAK-S12: VCU is authoritative for charge-cycle lifecycle. The charger
+// keeps hardware-level wisdom (EVSE pilot detection, plug-out safety,
+// fault detection, current ramping) but obeys vcucmd for "should I be
+// charging right now?" — exactly mirroring the Dilong OBC_ControlCMD
+// pattern so the VCU's two charger paths can share code/state.
+//
+// VCUCMDS vocabulary (see include/param_prj.h):
+//   0 Charging — VCU wants current; walk to / hold at EVSEACTIVATE
+//   1 Stopped  — VCU has no active cycle; sit idle (no current)
+//   2 Complete — VCU has terminated the cycle; drop to STOP
+//
+// Self-decided exits from EVSEACTIVATE (CheckVoltage, CheckTimeout) are
+// gone — those were band-aids for the absence of an authoritative VCU
+// stop signal. CheckUnplugged() still owns hardware safety from every
+// state; CheckChargerFaults() still bails on real module faults.
 void ChargerStateMachine()
 {
    static states state = OFF;
    int configuredChargers = Param::GetInt(Param::chargerena);
+   int vcucmd = Param::GetInt(Param::vcucmd);
 
    if (!Param::GetBool(Param::enable))
    {
@@ -316,6 +332,9 @@ void ChargerStateMachine()
          Param::SetInt(Param::opmode, 0);
          DisableAll();
 
+         // OFF→WAITSTART requires hardware-level start condition (EVSE pilot
+         // or non-EVSE input). vcucmd is checked downstream — we still walk
+         // up to ENABLE on plug-in so the modules are ready when VCU says go.
          if (CheckStartCondition())
          {
             startTime = rtc_get_counter_val();
@@ -334,7 +353,15 @@ void ChargerStateMachine()
             DigIo::ch2ena_out.Set();
          if (configuredChargers & 4)
             DigIo::ch3ena_out.Set();
+
+         // Hold here until VCU says go (vcucmd=Charging) or terminates
+         // (vcucmd=Complete). Stopped keeps us armed but idle.
+         if (vcucmd == VCUCMD_COMPLETE)
+            state = STOP;
+         else if (vcucmd == VCUCMD_CHARGING)
             state = ACTIVATE;
+         else if (CheckUnplugged())
+            state = OFF;
          break;
       case ACTIVATE:
          Param::SetInt(Param::opmode, 1);
@@ -353,15 +380,88 @@ void ChargerStateMachine()
          DigIo::evseact_out.Set();
          DigIo::acpres_out.Set();
 
-         if (CheckVoltage() || CheckTimeout())
+         // 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)
+         {
+            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
+            {
+               // Final ramp tick: clear GPIOs (cuts AC enable; output decays
+               // through filter caps) and restore the PI reference to the
+               // current idcspnt/idclim so the NEXT EVSEACTIVATE entry
+               // doesn't sip at 0 A. Param::Change only fires on parameter
+               // changes; a normal restart cycle never touches idcspnt or
+               // idclim, so without this restore the PI controller stays
+               // pinned at 0 across the cycle. Iteration O bug — bench-
+               // confirmed 0.1 kW sip on limit-raise from COMPLETE.
+               DigIo::acpres_out.Clear();
+               DigIo::evseact_out.Clear();
+               dcCurController.SetRef(MIN(Param::Get(Param::idcspnt), Param::Get(Param::idclim)));
+               completeRampTicks       = 0;
+               completeRampOriginalRef = 0;
                state                   = STOP;
-         if (CheckUnplugged())
+            }
+            break;
+         }
+
+         // 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
+            // ready to resume on the next Charging command.
+            DigIo::ch1act_out.Clear();
+            DigIo::ch2act_out.Clear();
+            DigIo::ch3act_out.Clear();
+            DigIo::acpres_out.Clear();
+            DigIo::evseact_out.Clear();
+            Param::SetInt(Param::opmode, 0);
+            state = ENABLE;
+         }
+         else if (CheckUnplugged())
          {
             DigIo::acpres_out.Clear();
             DigIo::evseact_out.Clear();
             state = OFF;
          }
-         if (CheckChargerFaults())
+         else if (CheckChargerFaults())
          {
             DigIo::acpres_out.Clear();
             state = OFF;
@@ -373,6 +473,14 @@ void ChargerStateMachine()
 
          if (CheckUnplugged())
             state = OFF;
+         // S12 fix for the "raise ChargeLimit mid-COMPLETE wedges in STOP"
+         // bug: when VCU clears Complete (latch released because user raised
+         // limit above current SOC), drop to OFF so the natural OFF→WAITSTART
+         // →ENABLE→ACTIVATE→EVSEACTIVATE flow restarts charging next tick.
+         // Previously STOP only exited on physical unplug — wedge on every
+         // limit-raise.
+         else if (vcucmd != VCUCMD_COMPLETE)
+            state = OFF;
          break;
    }
 

src/chargercan.cpp

@@ -18,47 +18,62 @@
  */
 #include "chargercan.h"
 
+// SKUDAK-S8/S9: trimmed entry list to fit libopeninv's MAX_ITEMS=50 CANPOS pool.
+// The upstream teslacharger registers ~73 AddRecv+AddSend mappings, which
+// silently overflows the 50-slot pool and drops the last ~23 entries
+// (including the SKUDAK 0x211 broadcast). We dropped things we don't use:
+//
+//   - hwaclim duplicates on 0x209/0x20B (keep just 0x207; the three modules
+//     broadcast identical hardware AC limit values)                       -2
+//   - c2*/c3* iac, stt, tmp1/2/in (12 entries — full per-module diagnostics
+//     not needed; CheckChargerFaults only uses uac+flag, CalcTotals only
+//     uses idc+udc, and tmpobcmax aggregates fine from c1's 3 probes)    -12
+//   - CHAdeMO RX on 0x102 (canenable/idcspnt/udclim/soc — Polarity VCU
+//     doesn't use CHAdeMO at all)                                         -4
+//   - 0x368 version-only idle frame (purely cosmetic for stock OI UI)     -7
+//   - CHAdeMO TX on 0x108/0x109 (version, idclim, udc, idc, opmode —
+//     unused on this build)                                               -5
+//
+// Total dropped: 30 entries. From 73 → 42, with 8-slot headroom.
+//
+// -S9 RESTORED 8 entries the -S8 trim wrongly killed for 3-module Tesla OBCs:
+// c2/c3 uac (CheckChargerFaults active2/active3 detection),
+// c2/c3 flag (clears CheckAlive timeout under fault-check logic),
+// c2/c3 idc (CalcTotals current SUM — was reporting 1/3 of true delivery),
+// c2/c3 udc (CalcTotals voltage MAX). Without these the bench reported
+// ~2.7kW for what was actually 9.7kW going to the pack.
+//
+// 0x43c/0x44c TX kept on purpose — they're commands to OBC sub-modules 2/3,
+// required for multi-module operation. Drop them too only if pool pressure
+// returns and you've confirmed the bench is single-module.
 void ChargerCAN::MapMessages(CanMap* can)
 {
    can->AddRecv(Param::hwaclim, 0x207, 32, 9, 0.06666f); //gain 0.06666
-   can->AddRecv(Param::hwaclim, 0x209, 32, 9, 0.06666f); //gain 0.06666
-   can->AddRecv(Param::hwaclim, 0x20B, 32, 9, 0.06666f); //gain 0.06666
    can->AddRecv(Param::c1iac, 0x207, 41, 9, 0.06666f); //gain 0.06666
-   can->AddRecv(Param::c2iac, 0x209, 41, 9, 0.06666f); //gain 0.06666
-   can->AddRecv(Param::c3iac, 0x20B, 41, 9, 0.06666f); //gain 0.06666
    can->AddRecv(Param::c1uac, 0x207, 8, 8, 1);
-   can->AddRecv(Param::c2uac, 0x209, 8, 8, 1);
-   can->AddRecv(Param::c3uac, 0x20B, 8, 8, 1);
    can->AddRecv(Param::c1flag, 0x207, 17, 2, 1);
-   can->AddRecv(Param::c2flag, 0x209, 17, 2, 1);
-   can->AddRecv(Param::c3flag, 0x20B, 17, 2, 1);
    can->AddRecv(Param::c1stt, 0x217, 0, 8, 1);
-   can->AddRecv(Param::c2stt, 0x219, 0, 8, 1);
-   can->AddRecv(Param::c3stt, 0x21B, 0, 8, 1);
    can->AddRecv(Param::c1idc, 0x227, 32, 16, 0.000839233f); //gain 0.000839233
-   can->AddRecv(Param::c2idc, 0x229, 32, 16, 0.000839233f); //gain 0.000839233
-   can->AddRecv(Param::c3idc, 0x22B, 32, 16, 0.000839233f); //gain 0.000839233
    can->AddRecv(Param::c1udc, 0x227, 16, 16, 0.01052856f); //gain 0.01052856
-   can->AddRecv(Param::c2udc, 0x229, 16, 16, 0.01052856f); //gain 0.01052856
-   can->AddRecv(Param::c3udc, 0x22B, 16, 16, 0.01052856f); //gain 0.01052856
    can->AddRecv(Param::c1tmp1, 0x237, 0, 8, 1, -40); //offset -40°C
-   can->AddRecv(Param::c2tmp1, 0x239, 0, 8, 1, -40); //offset -40°C
-   can->AddRecv(Param::c3tmp1, 0x23B, 0, 8, 1, -40); //offset -40°C
    can->AddRecv(Param::c1tmp2, 0x237, 8, 8, 1, -40); //offset -40°C
-   can->AddRecv(Param::c2tmp2, 0x239, 8, 8, 1, -40); //offset -40°C
-   can->AddRecv(Param::c3tmp2, 0x23B, 8, 8, 1, -40); //offset -40°C
    can->AddRecv(Param::c1tmpin, 0x237, 40, 8, 1, -40); //offset -40°C
-   can->AddRecv(Param::c2tmpin, 0x239, 40, 8, 1, -40); //offset -40°C
-   can->AddRecv(Param::c3tmpin, 0x23B, 40, 8, 1, -40); //offset -40°C
-   //We don't have enough space for all messages, so we discard these
-   //can->AddRecv(Param::c1tmplim, 0x247, 0, 8, 7); //gain 0.234375
-   //can->AddRecv(Param::c2tmplim, 0x249, 0, 8, 7); //gain 0.234375
-   //can->AddRecv(Param::c3tmplim, 0x24B, 0, 8, 7); //gain 0.234375
-   /***** CHAdeMO RX *****/
-   can->AddRecv(Param::canenable, 0x102, 40, 1, 1);
-   can->AddRecv(Param::idcspnt,   0x102, 24, 8, 1);
-   can->AddRecv(Param::udclim,    0x102, 8, 16, 1);
-   can->AddRecv(Param::soc,       0x102, 48, 8, 1);
+
+   // SKUDAK-S9: module 2 RX. uac/flag prevent the CheckChargerFaults false-
+   // positive that would silently mask module-2 failure (active2 = (chargerena
+   // & 2) && (c2uac > 70V); without c2uac mapped, active2==false short-circuits
+   // the flag check). idc/udc are required so CalcTotals reports the SUM
+   // current and MAX voltage across all three Tesla OBC sub-modules.
+   can->AddRecv(Param::c2uac,  0x209, 8,  8,  1);
+   can->AddRecv(Param::c2flag, 0x209, 17, 2,  1);
+   can->AddRecv(Param::c2idc,  0x229, 32, 16, 0.000839233f);
+   can->AddRecv(Param::c2udc,  0x229, 16, 16, 0.01052856f);
+
+   // SKUDAK-S9: module 3 RX, same rationale.
+   can->AddRecv(Param::c3uac,  0x20B, 8,  8,  1);
+   can->AddRecv(Param::c3flag, 0x20B, 17, 2,  1);
+   can->AddRecv(Param::c3idc,  0x22B, 32, 16, 0.000839233f);
+   can->AddRecv(Param::c3udc,  0x22B, 16, 16, 0.01052856f);
 
    /***** Charger TX ******/
    can->AddSend(Param::udcspnt, 0x45c, 0, 16, 100); //gain 100
@@ -85,27 +100,34 @@ void ChargerCAN::MapMessages(CanMap* can)
    can->AddSend(Param::aclim, 0x44c, 16, 16, 1500);
    can->AddSend(Param::opmode, 0x44c, 32, 8, 154, 100);
 
-   can->AddSend(Param::version, 0x368, 0, 8, 0, 0x03);
-   can->AddSend(Param::version, 0x368, 8, 8, 0, 0x49);
-   can->AddSend(Param::version, 0x368, 16, 8, 0, 0x29);
-   can->AddSend(Param::version, 0x368, 24, 8, 0, 0x11);
-   can->AddSend(Param::version, 0x368, 40, 8, 0, 0x0c);
-   can->AddSend(Param::version, 0x368, 48, 8, 0, 0x40);
-   can->AddSend(Param::version, 0x368, 56, 8, 0, (int8_t)0xff);
-
-   /***** CHAdeMO TX *****/
-   can->AddSend(Param::version, 0x108, 8, 16, 107); //output 428V max = 4*107
-   can->AddSend(Param::idclim, 0x108, 24, 8, 1);
-   can->AddSend(Param::udc, 0x109, 8, 16, 1);
-   can->AddSend(Param::idc, 0x109, 24, 16, 1);
-   can->AddSend(Param::opmode, 0x109, 40, 3, 5); //Set charging and connlock at once
-
-   /***** SKUDAK VCU command RX (0x212) — SKUDAK-516 user ChargeLimit *****/
-   // Byte 0: ChargeLimit_pct (0-100). Bytes 1-7 reserved 0x00.
-   // Param::Change(vcuchglim) translates % to udcspnt setpoint (see src/main.cpp).
-   // VCU broadcasts every 200 ms once teslacharger detected; charger holds last
-   // value if VCU goes silent.
+   /***** SKUDAK VCU command RX (0x212) — SKUDAK-516 chglim + S10 udclim + S12 vcucmd *****/
+   // Byte 0:    ChargeLimit_pct (0-100). Param::Change(vcuchglim) translates
+   //            % to udcspnt setpoint (see src/main.cpp).
+   // Bytes 1-2: udclim_V (uint16 LE). DEPRECATED in -S11 but mapping kept for
+   //            backward compat with -S10 VCU TX. New VCU always sends 398V
+   //            (= the flash default), so this RX is a no-op. Old -S10 trick
+   //            (VCU sends 200V to force CheckVoltage() STOP) was unreliable
+   //            because c1udc/c2udc/c3udc collapse < 200V once VCU opens HV
+   //            contactors, never accumulating 10 ticks > udclim. Defensive
+   //            clamp in Param::Change(udclim) ignores values < 50 V (would
+   //            otherwise turn an old-VCU bench into a never-charges brick).
+   // Byte 3:    vcucmd (uint8, S12 — was binary vcustop in S11). Three states
+   //            mirror the Dilong OBC_ControlCMD vocabulary 1:1 so VCU code
+   //            paths can be reused across charger families:
+   //              0 = Charging — walk to / hold at EVSEACTIVATE, produce current
+   //              1 = Stopped  — sit idle in OFF/WAITSTART/ENABLE, no current
+   //              2 = Complete — VCU declares cycle done; drop to STOP
+   //            VCU is now authoritative for lifecycle. Self-decided
+   //            EVSEACTIVATE exits (CheckVoltage, CheckTimeout) are gone;
+   //            STOP also exits to OFF when vcucmd flips back from Complete
+   //            to Stopped/Charging so the natural restart path runs (fixes
+   //            the "raise limit mid-COMPLETE doesn't resume" wedge in S11).
+   // Bytes 4-7: reserved 0x00.
+   // VCU broadcasts every 200 ms once teslacharger detected; charger holds
+   // last received values if VCU goes silent.
    can->AddRecv(Param::vcuchglim, 0x212, 0,  8,  1);
+   can->AddRecv(Param::udclim,    0x212, 8,  16, 1);
+   can->AddRecv(Param::vcucmd,    0x212, 24, 8,  1);
 
    /***** SKUDAK VCU telemetry (0x211) — SKUDAK-448 expanded charger telemetry *****/
    // Byte 0:    state     (0=Off, 1=WaitStart, 2=Enable, 3=Activate, 4=Run, 5=Stop)

src/main.cpp

@@ -108,20 +108,41 @@ static void Ms100Task(void)
 
 static void MapChargerMessages()
 {
+   // SKUDAK: Reentrancy guard. canMap->Clear() (libopeninv canmap.cpp) ends
+   // with canHardware->ClearUserMessages(), which fires the HandleClear
+   // callback below — which calls back into THIS function. If this function
+   // ever calls Clear() itself, the chain becomes infinite recursion → stack
+   // overflow → HardFault before the terminal/web UI come up (this is what
+   // bricked -S6 on Kyle's bench, see PR #8 postmortem). The static guard
+   // makes any future "accidental Clear() inside the rebuild path" a no-op
+   // re-entry rather than a chip-bricking fault. Safe because this function
+   // is only invoked from main() and from the HandleClear callback, both
+   // single-threaded contexts; never from an ISR.
+   static bool in_progress = false;
+   if (in_progress) return;
+
    uint32_t dummyId;
    uint8_t dummyOfs;
    int8_t dummyAdd, dummyLen;
    float dummyGain;
    bool dummyrx;
 
-   //check sample value, if it is mapped assume valid CAN map
-   if (canMap->FindMap(Param::hwaclim, dummyId, dummyOfs, dummyLen, dummyGain, dummyAdd, dummyrx)) return;
-
-   //canMap->Clear();
+   // SKUDAK: tmpobcmax is the canary for the -S5+ CAN-map schema. If it's
+   // already mapped, the persistent flash map is up-to-date — preserve it
+   // and any user customizations. If it's NOT mapped, the saved map is
+   // from an older firmware that didn't broadcast OBC temp on 0x211 byte 7.
+   //
+   // We deliberately do NOT call canMap->Clear() here. Clear() triggers
+   // HandleClear, and the recursion is fatal (see guard comment above). The
+   // upgrade path is: user issues "canclear" via the openinverter terminal
+   // or web UI to nuke the stale map manually. That single Clear fires
+   // HandleClear once, this function re-runs additively, and Save() persists.
+   if (canMap->FindMap(Param::tmpobcmax, dummyId, dummyOfs, dummyLen, dummyGain, dummyAdd, dummyrx)) return;
 
+   in_progress = true;
    ChargerCAN::MapMessages(canMap);
-
    canMap->Save();
+   in_progress = false;
 }
 
 /** This function is called when the user changes a parameter */
@@ -140,6 +161,18 @@ void Param::Change(Param::PARAM_NUM paramNum)
          spnt = MIN(Param::Get(Param::idcspnt), Param::Get(Param::idclim));
          dcCurController.SetRef(spnt);
          break;
+      case Param::udclim:
+         // SKUDAK-S11: defensive clamp. udclim is now reverse-mapped from CAN
+         // (chargercan.cpp), and a pre-PR47 VCU sends 0 in 0x212 bytes 1-2.
+         // udclim=0 would make CheckVoltage() fire on every tick (udc > 0)
+         // and prevent any charging. If we see a value below the documented
+         // min (50V), restore the safe default. Trivial cost — fires only on
+         // CAN RX of udclim (200 ms cadence) and only ever does work when
+         // the value is bogus.
+         if (Param::GetInt(Param::udclim) < 50) {
+            Param::SetInt(Param::udclim, 398);
+         }
+         break;
       case Param::vcuchglim:
       {
          // SKUDAK-516: VCU sends user-set ChargeLimit_pct on CAN 0x212. Translate