Add fire alarm handling for DC30 CCS main controller.

Latch fire alarm until reboot, block recovery commands, and send periodic Everest ESTOP while active.

Co-authored-by: Cursor <cursoragent@cursor.com>

Core/Src/fire_alarm.c

@@ -0,0 +1,74 @@
+#include "fire_alarm.h"
+#include "serial_control.h"
+#include "charger_control.h"
+#include "connector.h"
+#include "serial.h"
+#include "cp.h"
+#include "debug.h"
+
+static uint8_t fire_alarm_latched = 0;
+static uint32_t fire_alarm_last_estop_tick = 0;
+
+extern CCS_ConnectorState_t CCS_ConnectorState;
+
+uint8_t FireAlarm_IsLatched(void) {
+    return fire_alarm_latched;
+}
+
+uint8_t FireAlarm_IsBlockingCommand(uint8_t command_code) {
+    if (!fire_alarm_latched) {
+        return 0;
+    }
+
+    switch (command_code) {
+        case CMD_GET_STATUS:
+        case CMD_GET_INFO:
+        case CMD_GET_LOG:
+        case CMD_DEVICE_RESET:
+            return 0;
+        default:
+            return 1;
+    }
+}
+
+void FireAlarm_Activate(void) {
+    if (fire_alarm_latched) {
+        return;
+    }
+
+    fire_alarm_latched = 1;
+    CONN.chargingError = CONN_ERR_FIRE_ALARM;
+    CONN.connControl = CMD_STOP;
+    CONN.EnableOutput = 0;
+
+    log_printf(LOG_ERR, "FIRE ALARM activated\n");
+
+    CCS_SendEmergencyStop();
+    fire_alarm_last_estop_tick = HAL_GetTick();
+    CP_SetDuty(100);
+    CCS_ConnectorState = CCS_DISABLED;
+    CONN_SetState(Disabled);
+}
+
+void FireAlarm_Maintain(void) {
+    if (!fire_alarm_latched) {
+        return;
+    }
+
+    CONN.chargingError = CONN_ERR_FIRE_ALARM;
+    CONN.EnableOutput = 0;
+    CP_SetDuty(100);
+
+    if ((int32_t)(HAL_GetTick() - fire_alarm_last_estop_tick) >= 1000) {
+        CCS_SendEmergencyStop();
+        fire_alarm_last_estop_tick = HAL_GetTick();
+    }
+
+    if (CCS_ConnectorState != CCS_DISABLED && CCS_ConnectorState != CCS_UNKNOWN) {
+        CCS_ConnectorState = CCS_DISABLED;
+    }
+
+    if (CONN.connState != Disabled) {
+        CONN_SetState(Disabled);
+    }
+}