diff --git a/ESP32_CAN_Logger-a.ino b/ESP32_CAN_Logger-a.ino
index 604ffb9..ab55fe6 100644
--- a/ESP32_CAN_Logger-a.ino
+++ b/ESP32_CAN_Logger-a.ino
@@ -275,6 +275,10 @@ char startLogicOp[4] = "OR";
 char stopLogicOp[4] = "OR";
 bool autoTriggerActive = false;
 bool autoTriggerLogCSV = false;  // 🆕 Auto Trigger용 CSV 형식 설정
+
+// 🆕 File Format 저장 변수
+bool savedCanLogFormatCSV = false;  // 저장된 CAN 로그 형식 (BIN=false, CSV=true)
+
 volatile bool serialLoggingEnabled = false;
 volatile bool serial2LoggingEnabled = false; // ⭐ Serial2 추가
 volatile bool sdCardReady = false;
@@ -298,7 +302,7 @@ volatile uint64_t serialLogStartTime = 0;
 volatile uint64_t serial2LogStartTime = 0;     // ⭐ Serial2 추가
 
 // 기타 전역 변수
-MCP2515Mode currentMcpMode = MCP_MODE_LISTEN_ONLY;
+MCP2515Mode currentMcpMode;
 SoftWire rtcWire(RTC_SDA, RTC_SCL);
 char rtcSyncBuffer[20];
 CAN_SPEED currentCanSpeed = CAN_1000KBPS;
@@ -348,12 +352,23 @@ void resetMCP2515() {
     // 4. MCP2515 재초기화
     mcp2515.reset();
     delay(100);
+    
+    // ✅ Preferences에서 설정 불러오기
+    preferences.begin("can-logger", true);
+    int speedIndex = preferences.getInt("can_speed", 3);
+    if (speedIndex >= 0 && speedIndex < 4) {
+        currentCanSpeed = canSpeedValues[speedIndex];
+    }
+    int savedMode = preferences.getInt("mcp_mode", 1);
+    if (savedMode >= 0 && savedMode <= 3) {
+        currentMcpMode = (MCP2515Mode)savedMode;
+    }
+    preferences.end();
+    
+    Serial.printf("🔧 resetMCP2515: Speed=%d, Mode=%d\n", (int)currentCanSpeed, (int)currentMcpMode);
+
     mcp2515.setBitrate(currentCanSpeed, MCP_8MHZ);
     delay(10);
-    mcp2515.setListenOnlyMode();
-    //currentMcpMode = MCP_MODE_LISTEN_ONLY;
-    
-    
     
     // 5. 모드 설정 (Normal/Loopback/Listen Only)
     if (currentMcpMode == MCP_MODE_NORMAL) {
@@ -639,10 +654,15 @@ void loadSettings() {
     }
     
     int savedMode = preferences.getInt("mcp_mode", 1);
+    Serial.printf("📥 loadSettings: MCP Mode = %d\n", savedMode);
     if (savedMode >= 0 && savedMode <= 3) {
         currentMcpMode = (MCP2515Mode)savedMode;
     }
     
+    // 🆕 File Format 불러오기
+    savedCanLogFormatCSV = preferences.getBool("can_format_csv", false);
+    Serial.printf("📥 loadSettings: CAN Format = %s\n", savedCanLogFormatCSV ? "CSV" : "BIN");
+    
     loadSerialSettings();
     preferences.end();
 }
@@ -833,9 +853,19 @@ void saveAutoTriggerSettings() {
     
     preferences.putBool("enabled", autoTriggerEnabled);
     preferences.putBool("logCSV", autoTriggerLogCSV);  // 🆕 로그 형식 저장
+    Serial.printf("💾 Save: autoTriggerLogCSV = %d\n", autoTriggerLogCSV);
     preferences.putString("start_logic", startLogicOp);
     preferences.putString("stop_logic", stopLogicOp);
     
+    // 디버그: Start Triggers 저장
+    Serial.printf("💾 Save: startTriggerCount = %d\n", startTriggerCount);
+    for (int i = 0; i < startTriggerCount; i++) {
+        Serial.printf("  [%d] ID=0x%X, Bit=%d, Len=%d, Op=%s, Val=%ld, En=%d\n", 
+                      i, startTriggers[i].canId, startTriggers[i].startBit, 
+                      startTriggers[i].bitLength, startTriggers[i].op, 
+                      startTriggers[i].value, startTriggers[i].enabled);
+    }
+    
     preferences.putInt("start_count", startTriggerCount);
     for (int i = 0; i < startTriggerCount; i++) {
         char key[32];
@@ -884,6 +914,7 @@ void loadAutoTriggerSettings() {
     
     autoTriggerEnabled = preferences.getBool("enabled", false);
     autoTriggerLogCSV = preferences.getBool("logCSV", false);  // 🆕 로그 형식 로드
+    Serial.printf("📥 Load: autoTriggerLogCSV = %d\n", autoTriggerLogCSV);
     preferences.getString("start_logic", startLogicOp, sizeof(startLogicOp));
     preferences.getString("stop_logic", stopLogicOp, sizeof(stopLogicOp));
     
@@ -914,6 +945,15 @@ void loadAutoTriggerSettings() {
         startTriggers[i].enabled = preferences.getBool(key, true);
     }
     
+    // 디버그: Start Triggers 출력
+    Serial.printf("📥 Load: startTriggerCount = %d\n", startTriggerCount);
+    for (int i = 0; i < startTriggerCount; i++) {
+        Serial.printf("  [%d] ID=0x%X, Bit=%d, Len=%d, Op=%s, Val=%ld, En=%d\n", 
+                      i, startTriggers[i].canId, startTriggers[i].startBit, 
+                      startTriggers[i].bitLength, startTriggers[i].op, 
+                      startTriggers[i].value, startTriggers[i].enabled);
+    }
+    
     stopTriggerCount = preferences.getInt("stop_count", 0);
     if (stopTriggerCount > MAX_TRIGGERS) stopTriggerCount = MAX_TRIGGERS;
     
@@ -960,6 +1000,12 @@ void saveSettings() {
     }
     
     preferences.putInt("mcp_mode", (int)currentMcpMode);
+    Serial.printf("💾 MCP Mode 저장: %d\n", (int)currentMcpMode);
+    
+    // 🆕 File Format 저장
+    preferences.putBool("can_format_csv", savedCanLogFormatCSV);
+    Serial.printf("💾 CAN Format 저장: %s\n", savedCanLogFormatCSV ? "CSV" : "BIN");
+    
     saveSerialSettings();
     preferences.end();
 }
@@ -1082,6 +1128,7 @@ void rtcSyncTask(void *parameter) {
 // MCP2515 모드
 // ========================================
 bool setMCP2515Mode(MCP2515Mode mode) {
+    Serial.printf("🔧 MCP Mode 변경 요청: %d → ", (int)mode);
     const char* modeName;
     MCP2515::ERROR result;
     
@@ -1652,7 +1699,75 @@ void sequenceTask(void *parameter) {
 // WebSocket 이벤트 처리 (중요!)
 // ========================================
 void webSocketEvent(uint8_t num, WStype_t type, uint8_t *payload, size_t length) {
-    if (type == WStype_TEXT) {
+    // 🆕 WebSocket 연결 시 현재 설정 전송
+    if (type == WStype_CONNECTED) {
+        Serial.printf("[%u] ✅ WebSocket 연결됨\n", num);
+        
+        // 기본 설정 전송
+        DynamicJsonDocument settings(512);
+        settings["type"] = "currentSettings";
+        
+        int speedIndex = 3;
+        for (int i = 0; i < 4; i++) {
+            if (canSpeedValues[i] == currentCanSpeed) {
+                speedIndex = i;
+                break;
+            }
+        }
+        settings["canSpeed"] = speedIndex;
+        settings["mcpMode"] = (int)currentMcpMode;
+        settings["autoTriggerEnabled"] = autoTriggerEnabled;
+        settings["autoTriggerLogCSV"] = autoTriggerLogCSV;
+        
+        String json;
+        serializeJson(settings, json);
+        webSocket.sendTXT(num, json);
+        
+        // Auto Trigger 설정도 전송
+        if (autoTriggerEnabled) {
+            delay(50);  // 메시지 간격
+            
+            DynamicJsonDocument autoTrigger(2048);
+            autoTrigger["type"] = "autoTriggers";
+            autoTrigger["enabled"] = autoTriggerEnabled;
+            autoTrigger["logFormat"] = autoTriggerLogCSV ? "csv" : "bin";
+            autoTrigger["startLogic"] = startLogicOp;
+            autoTrigger["stopLogic"] = stopLogicOp;
+            autoTrigger["startFormula"] = startFormula;
+            autoTrigger["stopFormula"] = stopFormula;
+            
+            JsonArray startArray = autoTrigger.createNestedArray("startTriggers");
+            for (int i = 0; i < startTriggerCount; i++) {
+                JsonObject t = startArray.createNestedObject();
+                char idStr[10];
+                sprintf(idStr, "0x%03X", startTriggers[i].canId);
+                t["canId"] = idStr;
+                t["startBit"] = startTriggers[i].startBit;
+                t["bitLength"] = startTriggers[i].bitLength;
+                t["op"] = startTriggers[i].op;
+                t["value"] = (long)startTriggers[i].value;
+                t["enabled"] = startTriggers[i].enabled;
+            }
+            
+            JsonArray stopArray = autoTrigger.createNestedArray("stopTriggers");
+            for (int i = 0; i < stopTriggerCount; i++) {
+                JsonObject t = stopArray.createNestedObject();
+                char idStr[10];
+                sprintf(idStr, "0x%03X", stopTriggers[i].canId);
+                t["canId"] = idStr;
+                t["startBit"] = stopTriggers[i].startBit;
+                t["bitLength"] = stopTriggers[i].bitLength;
+                t["op"] = stopTriggers[i].op;
+                t["value"] = (long)stopTriggers[i].value;
+                t["enabled"] = stopTriggers[i].enabled;
+            }
+            
+            String autoJson;
+            serializeJson(autoTrigger, autoJson);
+            webSocket.sendTXT(num, autoJson);
+        }
+    }
+    else if (type == WStype_TEXT) {
         DynamicJsonDocument doc(44384);
         DeserializationError error = deserializeJson(doc, payload);
         
@@ -2242,6 +2357,23 @@ void webSocketEvent(uint8_t num, WStype_t type, uint8_t *payload, size_t length)
             serializeJson(response, json);
             webSocket.sendTXT(num, json);
         }
+        // 🆕 CAN File Format 저장 명령 (메인 페이지용)
+        else if (strcmp(cmd, "saveCanFormat") == 0) {
+            const char* format = doc["format"];
+            if (format) {
+                savedCanLogFormatCSV = (strcmp(format, "csv") == 0);
+                saveSettings();
+                Serial.printf("💾 CAN File Format 저장: %s\n", savedCanLogFormatCSV ? "CSV" : "BIN");
+            }
+            
+            DynamicJsonDocument response(128);
+            response["type"] = "canFormatSaved";
+            response["format"] = savedCanLogFormatCSV ? "csv" : "bin";
+            
+            String json;
+            serializeJson(response, json);
+            webSocket.sendTXT(num, json);
+        }
         else if (strcmp(cmd, "setStartTriggers") == 0) {
             JsonArray triggers = doc["triggers"];
             strcpy(startLogicOp, doc["logic"] | "OR");
@@ -2698,6 +2830,9 @@ void webUpdateTask(void *parameter) {
             doc["lowVoltage"] = powerStatus.lowVoltage;
             doc["mcpMode"] = (int)currentMcpMode;
             
+            // 🆕 저장된 File Format 전송
+            doc["savedCanFormat"] = savedCanLogFormatCSV ? "csv" : "bin";
+            
             if (loggingEnabled && currentFilename[0] != '\0') {
                 doc["currentFile"] = String(currentFilename);
             } else {
@@ -2925,12 +3060,20 @@ void setup() {
     
     mcp2515.reset();
     delay(100);
+    // ✅ loadSettings()에서 이미 불러왔으므로 중복 제거
     mcp2515.setBitrate(currentCanSpeed, MCP_8MHZ);
     delay(10);
-    mcp2515.setListenOnlyMode();
-    //currentMcpMode = MCP_MODE_LISTEN_ONLY;
-    currentMcpMode =(MCP2515Mode)preferences.getInt("mcp_mode", 1);
-    
+    Serial.printf("🔧 Setup: MCP Mode = %d\n", (int)currentMcpMode);
+
+    // 5. 모드 설정 (Normal/Loopback/Listen Only)
+    if (currentMcpMode == MCP_MODE_NORMAL) {
+        mcp2515.setNormalMode();
+    } else if (currentMcpMode == MCP_MODE_LOOPBACK) {
+        mcp2515.setLoopbackMode();
+    } else {
+        mcp2515.setListenOnlyMode();
+    }
+
     delay(50);
     
     // 버퍼 클리어
@@ -3139,4 +3282,3 @@ void loop() {
         lastPrint = millis();
     }
 }
-
diff --git a/index.h b/index.h
index 9583775..d6ca756 100644
--- a/index.h
+++ b/index.h
@@ -971,6 +971,8 @@ const char index_html[] PROGMEM = R"rawliteral(
                             <span class="format-info">(Text - Excel Ready)</span>
                         </label>
                     </div>
+                    <button onclick="saveFileFormat()" style="background: linear-gradient(135deg, #667eea 0%, #764ba2 100%); padding: 8px 16px;">💾 Save</button>
+                    <span id="format-save-status" style="color: #11998e; font-size: 0.85em; font-weight: 600;"></span>
                 </div>
                 <div class="control-row">
                     <button onclick="startLogging()" style="background: linear-gradient(135deg, #11998e 0%, #38ef7d 100%);">Start Logging</button>
@@ -1153,6 +1155,9 @@ const char index_html[] PROGMEM = R"rawliteral(
         let commentingFile = '';
         // hasInitialSync 제거 - 매번 자동 동기화
         
+        // 🆕 File Format 동기화 플래그
+        window.canFormatSynced = false;
+        
         // 🎯 Auto Trigger 전역 변수
         let startTriggers = [];
         let stopTriggers = [];
@@ -1236,6 +1241,7 @@ const char index_html[] PROGMEM = R"rawliteral(
                 document.getElementById('sync-status').textContent = '연결 끊김';
                 document.getElementById('sync-status').style.color = '#f45c43';
                 mcpModeSynced = false;  // 🆕 재연결 시 다시 동기화하도록 플래그 리셋
+                window.canFormatSynced = false;  // 🆕 File Format도 재동기화
                 setTimeout(initWebSocket, 3000);
             };
             
@@ -1332,6 +1338,15 @@ const char index_html[] PROGMEM = R"rawliteral(
                     else if (data.type === 'stopTriggersSet') {
                         console.log('✅ Stop triggers saved:', data.count);
                     }
+                    // 🆕 File Format 저장 결과 처리
+                    else if (data.type === 'canFormatSaved') {
+                        console.log('✅ CAN Format saved:', data.format);
+                        const statusSpan = document.getElementById('format-save-status');
+                        if (statusSpan) {
+                            statusSpan.textContent = '✓ Saved: ' + data.format.toUpperCase();
+                            setTimeout(() => { statusSpan.textContent = ''; }, 3000);
+                        }
+                    }
                     
                     // Auto Trigger 상태 업데이트 (update 메시지에서)
                     if (data.autoTriggerEnabled !== undefined) {
@@ -1430,6 +1445,19 @@ const char index_html[] PROGMEM = R"rawliteral(
                 }
             }
             
+            // 🆕 저장된 File Format 적용 (최초 접속 시 한 번만)
+            if (data.savedCanFormat && !window.canFormatSynced) {
+                const formatRadios = document.getElementsByName('can-format');
+                for (const radio of formatRadios) {
+                    if (radio.value === data.savedCanFormat) {
+                        radio.checked = true;
+                        break;
+                    }
+                }
+                window.canFormatSynced = true;
+                console.log('✅ Loaded saved CAN format:', data.savedCanFormat);
+            }
+            
             // 현재 파일
             currentLoggingFile = data.currentFile || '';
             if (data.currentFile) {
@@ -1713,6 +1741,26 @@ const char index_html[] PROGMEM = R"rawliteral(
             console.log('MCP2515 mode set to:', modeName);
         }
         
+        // 🆕 File Format 저장 함수
+        function saveFileFormat() {
+            if (ws && ws.readyState === WebSocket.OPEN) {
+                let canFormat = 'bin';
+                const formatRadios = document.getElementsByName('can-format');
+                for (const radio of formatRadios) {
+                    if (radio.checked) {
+                        canFormat = radio.value;
+                        break;
+                    }
+                }
+                
+                ws.send(JSON.stringify({
+                    cmd: 'saveCanFormat',
+                    format: canFormat
+                }));
+                
+                console.log('Save CAN format:', canFormat);
+            }
+        }
         
         function startLogging() {
             if (ws && ws.readyState === WebSocket.OPEN) {