diff --git a/test_i2c_reset/ESP32_CAN_Logger.ino b/test_i2c_reset/ESP32_CAN_Logger.ino
index ee6c226..f3e55d0 100644
--- a/test_i2c_reset/ESP32_CAN_Logger.ino
+++ b/test_i2c_reset/ESP32_CAN_Logger.ino
@@ -1,842 +1,975 @@
-/*
- * Byun CAN Logger with Web Interface + Time Synchronization
- * Version: 1.2
- */
-
-#include <Arduino.h>
-#include <SPI.h>
-#include <mcp2515.h>
-#include <SD.h>
-#include <WiFi.h>
-#include <WebServer.h>
-#include <WebSocketsServer.h>
-#include <freertos/FreeRTOS.h>
-#include <freertos/task.h>
-#include <freertos/queue.h>
-#include <freertos/semphr.h>
-#include <sys/time.h>
-#include <time.h>
-#include "index.h"
-#include "transmit.h"
-#include "graph.h"
-#include "graph_viewer.h"
-
-
-// GPIO 핀 정의
-#define CAN_INT_PIN 27
-
-// HSPI 핀 (CAN)
-#define HSPI_MISO 12
-#define HSPI_MOSI 13
-#define HSPI_SCLK 14
-#define HSPI_CS 15
-
-// VSPI 핀 (SD Card)
-#define VSPI_MISO 19
-#define VSPI_MOSI 23
-#define VSPI_SCLK 18
-#define VSPI_CS 5
-
-// 버퍼 설정
-#define CAN_QUEUE_SIZE 1000
-#define FILE_BUFFER_SIZE 8192
-#define MAX_FILENAME_LEN 64
-#define RECENT_MSG_COUNT 100
-#define MAX_TX_MESSAGES 20
-
-// CAN 메시지 구조체 - 마이크로초 단위 타임스탬프
-struct CANMessage {
-    uint64_t timestamp_us;  // 마이크로초 단위 Unix timestamp
-    uint32_t id;
-    uint8_t dlc;
-    uint8_t data[8];
-} __attribute__((packed));
-
-// 실시간 모니터링용 구조체
-struct RecentCANData {
-    CANMessage msg;
-    uint32_t count;
-};
-
-// CAN 송신용 구조체
-struct TxMessage {
-    uint32_t id;
-    bool extended;
-    uint8_t dlc;
-    uint8_t data[8];
-    uint32_t interval;
-    uint32_t lastSent;
-    bool active;
-};
-
-// 시간 동기화 상태
-struct TimeSyncStatus {
-    bool synchronized;
-    uint64_t lastSyncTime;
-    int32_t offsetUs;
-    uint32_t syncCount;
-} timeSyncStatus = {false, 0, 0, 0};
-
-// WiFi AP 설정
-const char* ssid = "Byun_CAN_Logger";
-const char* password = "12345678";
-
-// 전역 변수
-SPIClass hspi(HSPI);
-SPIClass vspi(VSPI);
-MCP2515 mcp2515(HSPI_CS, 10000000, &hspi);
-
-WebServer server(80);
-WebSocketsServer webSocket = WebSocketsServer(81);
-
-QueueHandle_t canQueue;
-SemaphoreHandle_t sdMutex;
-TaskHandle_t canRxTaskHandle = NULL;
-TaskHandle_t sdWriteTaskHandle = NULL;
-TaskHandle_t webTaskHandle = NULL;
-
-volatile bool loggingEnabled = false;
-volatile bool sdCardReady = false;
-File logFile;
-char currentFilename[MAX_FILENAME_LEN];
-uint8_t fileBuffer[FILE_BUFFER_SIZE];
-uint16_t bufferIndex = 0;
-
-// CAN 속도 설정
-CAN_SPEED currentCanSpeed = CAN_1000KBPS;
-const char* canSpeedNames[] = {"125K", "250K", "500K", "1M"};
-CAN_SPEED canSpeedValues[] = {CAN_125KBPS, CAN_250KBPS, CAN_500KBPS, CAN_1000KBPS};
-
-// 실시간 모니터링용
-RecentCANData recentData[RECENT_MSG_COUNT];
-uint32_t totalMsgCount = 0;
-uint32_t msgPerSecond = 0;
-uint32_t lastMsgCountTime = 0;
-uint32_t lastMsgCount = 0;
-
-// CAN 송신용
-TxMessage txMessages[MAX_TX_MESSAGES];
-uint32_t totalTxCount = 0;
-
-// 정밀한 현재 시간 가져오기 (마이크로초)
-uint64_t getMicrosecondTimestamp() {
-    struct timeval tv;
-    gettimeofday(&tv, NULL);
-    return (uint64_t)tv.tv_sec * 1000000ULL + (uint64_t)tv.tv_usec;
-}
-
-// 시간 동기화 설정
-void setSystemTime(uint64_t timestampMs) {
-    struct timeval tv;
-    tv.tv_sec = timestampMs / 1000;
-    tv.tv_usec = (timestampMs % 1000) * 1000;
-    settimeofday(&tv, NULL);
-    
-    timeSyncStatus.synchronized = true;
-    timeSyncStatus.lastSyncTime = getMicrosecondTimestamp();
-    timeSyncStatus.syncCount++;
-    
-    // 현재 시간 출력
-    time_t now = tv.tv_sec;
-    struct tm timeinfo;
-    localtime_r(&now, &timeinfo);
-    char timeStr[64];
-    strftime(timeStr, sizeof(timeStr), "%Y-%m-%d %H:%M:%S", &timeinfo);
-    
-    Serial.printf("⏰ 시간 동기화 완료: %s.%03d (동기화 횟수: %u)\n", 
-                  timeStr, (int)(tv.tv_usec / 1000), timeSyncStatus.syncCount);
-}
-
-// 함수 선언
-void changeCanSpeed(CAN_SPEED newSpeed);
-bool createNewLogFile();
-bool flushBuffer();
-void startLogging();
-void stopLogging();
-void canRxTask(void *pvParameters);
-void sdWriteTask(void *pvParameters);
-void sdMonitorTask(void *pvParameters);
-void sendFileList(uint8_t clientNum);
-void webSocketEvent(uint8_t num, WStype_t type, uint8_t * payload, size_t length);
-void handleCanTransmit(String msg);
-void handleStartMessage(String msg);
-void handleStopMessage(String msg);
-void handleTimeSync(String msg);
-void webUpdateTask(void *pvParameters);
-
-// CAN 인터럽트 핸들러
-void IRAM_ATTR canISR() {
-    BaseType_t xHigherPriorityTaskWoken = pdFALSE;
-    if (canRxTaskHandle != NULL) {
-        vTaskNotifyGiveFromISR(canRxTaskHandle, &xHigherPriorityTaskWoken);
-        portYIELD_FROM_ISR(xHigherPriorityTaskWoken);
-    }
-}
-
-// CAN 속도 변경
-void changeCanSpeed(CAN_SPEED newSpeed) {
-    detachInterrupt(digitalPinToInterrupt(CAN_INT_PIN));
-    mcp2515.reset();
-    mcp2515.setBitrate(newSpeed, MCP_8MHZ);
-    mcp2515.setNormalMode();
-    currentCanSpeed = newSpeed;
-    attachInterrupt(digitalPinToInterrupt(CAN_INT_PIN), canISR, FALLING);
-    Serial.printf("CAN 속도 변경: %s\n", canSpeedNames[newSpeed]);
-}
-
-// 새 로그 파일 생성 - 시간 기반 파일명
-bool createNewLogFile() {
-    if (logFile) {
-        logFile.flush();
-        logFile.close();
-        vTaskDelay(pdMS_TO_TICKS(10));
-    }
-    
-    // 현재 시간으로 파일명 생성
-    time_t now;
-    struct tm timeinfo;
-    time(&now);
-    localtime_r(&now, &timeinfo);
-    
-    char filename[MAX_FILENAME_LEN];
-    snprintf(filename, MAX_FILENAME_LEN, "/canlog_%04d%02d%02d_%02d%02d%02d.bin",
-             timeinfo.tm_year + 1900, 
-             timeinfo.tm_mon + 1, 
-             timeinfo.tm_mday,
-             timeinfo.tm_hour, 
-             timeinfo.tm_min, 
-             timeinfo.tm_sec);
-    
-    logFile = SD.open(filename, FILE_WRITE);
-    
-    if (!logFile) {
-        Serial.printf("파일 생성 실패: %s\n", filename);
-        return false;
-    }
-    
-    strncpy(currentFilename, filename, MAX_FILENAME_LEN);
-    Serial.printf("새 로그 파일 생성: %s\n", currentFilename);
-    
-    // 시간 동기화 경고
-    if (!timeSyncStatus.synchronized) {
-        Serial.println("⚠️  경고: 시간이 동기화되지 않았습니다! 웹페이지에서 시간 동기화를 실행하세요.");
-    }
-    
-    return true;
-}
-
-// 버퍼 플러시
-bool flushBuffer() {
-    if (bufferIndex == 0) return true;
-    
-    if (xSemaphoreTake(sdMutex, portMAX_DELAY) == pdTRUE) {
-        if (logFile) {
-            size_t written = logFile.write(fileBuffer, bufferIndex);
-            logFile.flush();
-            xSemaphoreGive(sdMutex);
-            
-            if (written != bufferIndex) {
-                Serial.println("SD 쓰기 오류!");
-                return false;
-            }
-            bufferIndex = 0;
-            return true;
-        }
-        xSemaphoreGive(sdMutex);
-    }
-    return false;
-}
-
-// 로깅 시작
-void startLogging() {
-    if (loggingEnabled) {
-        Serial.println("이미 로깅 중");
-        return;
-    }
-    
-    if (!sdCardReady) {
-        Serial.println("SD 카드가 준비되지 않음");
-        return;
-    }
-    
-    Serial.println("로깅 시작");
-    
-    if (xSemaphoreTake(sdMutex, pdMS_TO_TICKS(1000)) == pdTRUE) {
-        if (createNewLogFile()) {
-            loggingEnabled = true;
-            bufferIndex = 0;
-        }
-        xSemaphoreGive(sdMutex);
-    }
-}
-
-// 로깅 중지
-void stopLogging() {
-    if (!loggingEnabled) {
-        Serial.println("로깅이 실행 중이 아님");
-        return;
-    }
-    
-    Serial.println("로깅 정지");
-    loggingEnabled = false;
-    
-    flushBuffer();
-    
-    if (xSemaphoreTake(sdMutex, pdMS_TO_TICKS(1000)) == pdTRUE) {
-        if (logFile) {
-            logFile.close();
-        }
-        xSemaphoreGive(sdMutex);
-    }
-}
-
-// CAN 수신 태스크
-void canRxTask(void *pvParameters) {
-    struct can_frame frame;
-    CANMessage msg;
-    
-    Serial.println("CAN 수신 태스크 시작");
-    
-    while (1) {
-        ulTaskNotifyTake(pdTRUE, portMAX_DELAY);
-        
-        while (mcp2515.readMessage(&frame) == MCP2515::ERROR_OK) {
-            // 마이크로초 단위 타임스탬프
-            msg.timestamp_us = getMicrosecondTimestamp();
-            msg.id = frame.can_id;
-            msg.dlc = frame.can_dlc;
-            memcpy(msg.data, frame.data, 8);
-            
-            if (xQueueSend(canQueue, &msg, 0) != pdTRUE) {
-                static uint32_t lastWarning = 0;
-                if (millis() - lastWarning > 1000) {
-                    Serial.println("경고: CAN 큐 오버플로우!");
-                    lastWarning = millis();
-                }
-            }
-            
-            // 최근 메시지 저장 및 카운트 증가
-            bool found = false;
-            for (int i = 0; i < RECENT_MSG_COUNT; i++) {
-                if (recentData[i].msg.id == msg.id && recentData[i].msg.timestamp_us > 0) {
-                    recentData[i].msg = msg;
-                    recentData[i].count++;
-                    found = true;
-                    break;
-                }
-            }
-            
-            if (!found) {
-                for (int i = 0; i < RECENT_MSG_COUNT; i++) {
-                    if (recentData[i].msg.timestamp_us == 0) {
-                        recentData[i].msg = msg;
-                        recentData[i].count = 1;
-                        found = true;
-                        break;
-                    }
-                }
-                
-                if (!found) {
-                    static int replaceIndex = 0;
-                    recentData[replaceIndex].msg = msg;
-                    recentData[replaceIndex].count = 1;
-                    replaceIndex = (replaceIndex + 1) % RECENT_MSG_COUNT;
-                }
-            }
-            
-            totalMsgCount++;
-        }
-    }
-}
-
-// SD 쓰기 태스크
-void sdWriteTask(void *pvParameters) {
-    CANMessage msg;
-    
-    Serial.println("SD 쓰기 태스크 시작");
-    
-    while (1) {
-        if (xQueueReceive(canQueue, &msg, pdMS_TO_TICKS(100)) == pdTRUE) {
-            
-            if (loggingEnabled && sdCardReady) {
-                if (bufferIndex + sizeof(CANMessage) > FILE_BUFFER_SIZE) {
-                    if (!flushBuffer()) {
-                        continue;
-                    }
-                }
-                
-                memcpy(&fileBuffer[bufferIndex], &msg, sizeof(CANMessage));
-                bufferIndex += sizeof(CANMessage);
-            }
-        } else {
-            if (loggingEnabled && bufferIndex > 0) {
-                flushBuffer();
-            }
-        }
-    }
-}
-
-// SD 모니터 태스크
-void sdMonitorTask(void *pvParameters) {
-    Serial.println("SD 모니터 태스크 시작");
-    
-    while (1) {
-        bool cardPresent = SD.begin(VSPI_CS, vspi);
-        
-        if (cardPresent != sdCardReady) {
-            sdCardReady = cardPresent;
-            
-            if (sdCardReady) {
-                Serial.println("SD 카드 준비됨");
-            } else {
-                Serial.println("SD 카드 없음");
-                if (loggingEnabled) {
-                    stopLogging();
-                }
-            }
-        }
-        
-        vTaskDelay(pdMS_TO_TICKS(1000));
-    }
-}
-
-// 파일 목록 전송
-void sendFileList(uint8_t clientNum) {
-    String fileList = "{\"type\":\"files\",\"files\":[";
-    
-    if (!sdCardReady) {
-        fileList += "],\"error\":\"SD card not ready\"}";
-        webSocket.sendTXT(clientNum, fileList);
-        return;
-    }
-    
-    File root = SD.open("/");
-    if (!root) {
-        fileList += "],\"error\":\"Cannot open root directory\"}";
-        webSocket.sendTXT(clientNum, fileList);
-        return;
-    }
-    
-    File file = root.openNextFile();
-    bool first = true;
-    int fileCount = 0;
-    
-    while (file) {
-        if (!file.isDirectory()) {
-            String name = file.name();
-            if (name.startsWith("/")) name = name.substring(1);
-            
-            if (name.endsWith(".bin") || name.endsWith(".BIN")) {
-                if (!first) fileList += ",";
-                fileList += "{\"name\":\"" + name + "\",\"size\":" + String(file.size()) + "}";
-                first = false;
-                fileCount++;
-            }
-        }
-        file.close();
-        file = root.openNextFile();
-    }
-    root.close();
-    
-    fileList += "]}";
-    webSocket.sendTXT(clientNum, fileList);
-    
-    Serial.printf("파일 목록 전송: %d개\n", fileCount);
-}
-
-// CAN 메시지 전송 처리
-void handleCanTransmit(String msg) {
-    int idIdx = msg.indexOf("\"id\":\"") + 6;
-    int idEnd = msg.indexOf("\"", idIdx);
-    String idStr = msg.substring(idIdx, idEnd);
-    
-    int typeIdx = msg.indexOf("\"type\":\"") + 8;
-    String typeStr = msg.substring(typeIdx, typeIdx + 3);
-    bool extended = (typeStr == "ext");
-    
-    int dlcIdx = msg.indexOf("\"dlc\":") + 6;
-    int dlc = msg.substring(dlcIdx, dlcIdx + 1).toInt();
-    
-    int dataIdx = msg.indexOf("\"data\":\"") + 8;
-    String dataStr = msg.substring(dataIdx, dataIdx + 16);
-    
-    uint32_t canId = strtoul(idStr.c_str(), NULL, 16);
-    
-    uint8_t data[8] = {0};
-    for (int i = 0; i < dlc && i < 8; i++) {
-        String byteStr = dataStr.substring(i * 2, i * 2 + 2);
-        data[i] = strtoul(byteStr.c_str(), NULL, 16);
-    }
-    
-    struct can_frame frame;
-    frame.can_id = canId;
-    if (extended) frame.can_id |= CAN_EFF_FLAG;
-    frame.can_dlc = dlc;
-    memcpy(frame.data, data, 8);
-    
-    if (mcp2515.sendMessage(&frame) == MCP2515::ERROR_OK) {
-        totalTxCount++;
-        Serial.printf("CAN TX: 0x%X [%d]\n", canId, dlc);
-    }
-}
-
-// 주기 전송 시작
-void handleStartMessage(String msg) {
-    int indexIdx = msg.indexOf("\"index\":") + 8;
-    int index = msg.substring(indexIdx, indexIdx + 2).toInt();
-    
-    if (index >= 0 && index < MAX_TX_MESSAGES) {
-        int idIdx = msg.indexOf("\"id\":\"") + 6;
-        int idEnd = msg.indexOf("\"", idIdx);
-        String idStr = msg.substring(idIdx, idEnd);
-        
-        int typeIdx = msg.indexOf("\"type\":\"") + 8;
-        String typeStr = msg.substring(typeIdx, typeIdx + 3);
-        
-        int dlcIdx = msg.indexOf("\"dlc\":") + 6;
-        int dlc = msg.substring(dlcIdx, dlcIdx + 1).toInt();
-        
-        int dataIdx = msg.indexOf("\"data\":\"") + 8;
-        String dataStr = msg.substring(dataIdx, dataIdx + 16);
-        
-        int intervalIdx = msg.indexOf("\"interval\":") + 11;
-        int interval = msg.substring(intervalIdx, intervalIdx + 5).toInt();
-        
-        txMessages[index].id = strtoul(idStr.c_str(), NULL, 16);
-        txMessages[index].extended = (typeStr == "ext");
-        txMessages[index].dlc = dlc;
-        
-        for (int i = 0; i < 8; i++) {
-            String byteStr = dataStr.substring(i * 2, i * 2 + 2);
-            txMessages[index].data[i] = strtoul(byteStr.c_str(), NULL, 16);
-        }
-        
-        txMessages[index].interval = interval;
-        txMessages[index].lastSent = 0;
-        txMessages[index].active = true;
-        
-        Serial.printf("주기 전송 시작 [%d]: 0x%X\n", index, txMessages[index].id);
-    }
-}
-
-// 주기 전송 중지
-void handleStopMessage(String msg) {
-    int indexIdx = msg.indexOf("\"index\":") + 8;
-    int index = msg.substring(indexIdx, indexIdx + 2).toInt();
-    
-    if (index >= 0 && index < MAX_TX_MESSAGES) {
-        txMessages[index].active = false;
-        Serial.printf("주기 전송 중지 [%d]\n", index);
-    }
-}
-
-// 시간 동기화 처리
-void handleTimeSync(String msg) {
-    int timestampIdx = msg.indexOf("\"timestamp\":") + 12;
-    String timestampStr = msg.substring(timestampIdx);
-    timestampStr = timestampStr.substring(0, timestampStr.indexOf("}"));
-    
-    uint64_t clientTimestamp = strtoull(timestampStr.c_str(), NULL, 10);
-    
-    if (clientTimestamp > 0) {
-        setSystemTime(clientTimestamp);
-    }
-}
-
-// 웹소켓 이벤트 핸들러
-void webSocketEvent(uint8_t num, WStype_t type, uint8_t * payload, size_t length) {
-    switch(type) {
-        case WStype_DISCONNECTED:
-            Serial.printf("WebSocket #%u 연결 해제\n", num);
-            break;
-            
-        case WStype_CONNECTED:
-            {
-                IPAddress ip = webSocket.remoteIP(num);
-                Serial.printf("WebSocket #%u 연결: %d.%d.%d.%d\n", 
-                    num, ip[0], ip[1], ip[2], ip[3]);
-                sendFileList(num);
-                
-                // 시간 동기화 상태 전송
-                String syncStatus = "{\"type\":\"timeSyncStatus\",\"synchronized\":";
-                syncStatus += timeSyncStatus.synchronized ? "true" : "false";
-                syncStatus += ",\"syncCount\":" + String(timeSyncStatus.syncCount) + "}";
-                webSocket.sendTXT(num, syncStatus);
-            }
-            break;
-            
-        case WStype_TEXT:
-            {
-                String msg = String((char*)payload);
-                
-                if (msg.indexOf("\"cmd\":\"setSpeed\"") >= 0) {
-                    int speedIdx = msg.indexOf("\"speed\":") + 8;
-                    int speed = msg.substring(speedIdx, speedIdx + 1).toInt();
-                    
-                    if (speed >= 0 && speed < 4) {
-                        changeCanSpeed(canSpeedValues[speed]);
-                    }
-                } 
-                else if (msg.indexOf("\"cmd\":\"getFiles\"") >= 0) {
-                    sendFileList(num);
-                }
-                else if (msg.indexOf("\"cmd\":\"startLogging\"") >= 0) {
-                    startLogging();
-                }
-                else if (msg.indexOf("\"cmd\":\"stopLogging\"") >= 0) {
-                    stopLogging();
-                }
-                else if (msg.indexOf("\"cmd\":\"sendCan\"") >= 0) {
-                    handleCanTransmit(msg);
-                }
-                else if (msg.indexOf("\"cmd\":\"startMsg\"") >= 0) {
-                    handleStartMessage(msg);
-                }
-                else if (msg.indexOf("\"cmd\":\"stopMsg\"") >= 0) {
-                    handleStopMessage(msg);
-                }
-                else if (msg.indexOf("\"cmd\":\"stopAll\"") >= 0) {
-                    for (int i = 0; i < MAX_TX_MESSAGES; i++) {
-                        txMessages[i].active = false;
-                    }
-                }
-                else if (msg.indexOf("\"cmd\":\"syncTime\"") >= 0) {
-                    handleTimeSync(msg);
-                }
-            }
-            break;
-    }
-}
-
-// 웹 업데이트 태스크
-void webUpdateTask(void *pvParameters) {
-    uint32_t lastStatusUpdate = 0;
-    uint32_t lastCanUpdate = 0;
-    uint32_t lastTxStatusUpdate = 0;
-    const uint32_t CAN_UPDATE_INTERVAL = 500;
-    
-    Serial.println("웹 업데이트 태스크 시작");
-    
-    while (1) {
-        uint32_t now = millis();
-        
-        webSocket.loop();
-        
-        // 주기 전송 처리
-        for (int i = 0; i < MAX_TX_MESSAGES; i++) {
-            if (txMessages[i].active && (now - txMessages[i].lastSent >= txMessages[i].interval)) {
-                struct can_frame frame;
-                frame.can_id = txMessages[i].id;
-                if (txMessages[i].extended) frame.can_id |= CAN_EFF_FLAG;
-                frame.can_dlc = txMessages[i].dlc;
-                memcpy(frame.data, txMessages[i].data, 8);
-                
-                if (mcp2515.sendMessage(&frame) == MCP2515::ERROR_OK) {
-                    totalTxCount++;
-                    txMessages[i].lastSent = now;
-                }
-            }
-        }
-        
-        // TX 상태 업데이트
-        if (now - lastTxStatusUpdate >= 1000) {
-            String txStatus = "{\"type\":\"txStatus\",\"count\":" + String(totalTxCount) + "}";
-            webSocket.broadcastTXT(txStatus);
-            lastTxStatusUpdate = now;
-        }
-        
-        // 상태 업데이트
-        if (now - lastStatusUpdate >= 1000) {
-            if (now - lastMsgCountTime >= 1000) {
-                msgPerSecond = totalMsgCount - lastMsgCount;
-                lastMsgCount = totalMsgCount;
-                lastMsgCountTime = now;
-            }
-            
-            String status = "{\"type\":\"status\",";
-            status += "\"logging\":" + String(loggingEnabled ? "true" : "false") + ",";
-            status += "\"sdReady\":" + String(sdCardReady ? "true" : "false") + ",";
-            status += "\"msgCount\":" + String(totalMsgCount) + ",";
-            status += "\"msgSpeed\":" + String(msgPerSecond) + ",";
-            status += "\"timeSync\":" + String(timeSyncStatus.synchronized ? "true" : "false") + ",";
-            status += "\"syncCount\":" + String(timeSyncStatus.syncCount) + ",";
-            
-            if (loggingEnabled && logFile) {
-                status += "\"currentFile\":\"" + String(currentFilename) + "\"";
-            } else {
-                status += "\"currentFile\":\"\"";
-            }
-            status += "}";
-            
-            webSocket.broadcastTXT(status);
-            lastStatusUpdate = now;
-        }
-        
-        // CAN 메시지 일괄 업데이트
-        if (now - lastCanUpdate >= CAN_UPDATE_INTERVAL) {
-            String canBatch = "{\"type\":\"canBatch\",\"messages\":[";
-            bool first = true;
-            
-            for (int i = 0; i < RECENT_MSG_COUNT; i++) {
-                if (recentData[i].msg.timestamp_us > 0) {
-                    CANMessage* msg = &recentData[i].msg;
-                    
-                    if (!first) canBatch += ",";
-                    first = false;
-                    
-                    canBatch += "{\"id\":\"";
-                    if (msg->id < 0x10) canBatch += "0";
-                    if (msg->id < 0x100) canBatch += "0";
-                    if (msg->id < 0x1000) canBatch += "0";
-                    canBatch += String(msg->id, HEX);
-                    canBatch += "\",\"dlc\":" + String(msg->dlc);
-                    canBatch += ",\"data\":\"";
-                    
-                    for (int j = 0; j < msg->dlc; j++) {
-                        if (msg->data[j] < 0x10) canBatch += "0";
-                        canBatch += String(msg->data[j], HEX);
-                        if (j < msg->dlc - 1) canBatch += " ";
-                    }
-                    
-                    // 마이크로초 타임스탬프를 밀리초로 변환하여 전송
-                    uint64_t timestamp_ms = msg->timestamp_us / 1000;
-                    canBatch += "\",\"timestamp\":" + String((uint32_t)timestamp_ms);
-                    canBatch += ",\"count\":" + String(recentData[i].count) + "}";
-                }
-            }
-            
-            canBatch += "]}";
-            
-            if (!first) {
-                webSocket.broadcastTXT(canBatch);
-            }
-            
-            lastCanUpdate = now;
-        }
-        
-        vTaskDelay(pdMS_TO_TICKS(50));
-    }
-}
-
-void setup() {
-    Serial.begin(115200);
-    delay(1000);
-    Serial.println("\n========================================");
-    Serial.println("  ESP32 CAN Logger with Time Sync  ");
-    Serial.println("========================================");
-    
-    memset(recentData, 0, sizeof(recentData));
-    memset(txMessages, 0, sizeof(txMessages));
-    
-    pinMode(CAN_INT_PIN, INPUT_PULLUP);
-    
-    hspi.begin(HSPI_SCLK, HSPI_MISO, HSPI_MOSI, HSPI_CS);
-    vspi.begin(VSPI_SCLK, VSPI_MISO, VSPI_MOSI, VSPI_CS);
-    
-    mcp2515.reset();
-    mcp2515.setBitrate(CAN_1000KBPS, MCP_8MHZ);
-    mcp2515.setNormalMode();
-    Serial.println("✓ MCP2515 초기화 완료");
-    
-    if (SD.begin(VSPI_CS, vspi)) {
-        sdCardReady = true;
-        Serial.println("✓ SD 카드 초기화 완료");
-    } else {
-        Serial.println("✗ SD 카드 초기화 실패");
-    }
-    
-    WiFi.softAP(ssid, password);
-    Serial.print("✓ AP IP: ");
-    Serial.println(WiFi.softAPIP());
-    
-    webSocket.begin();
-    webSocket.onEvent(webSocketEvent);
-    
-    server.on("/", HTTP_GET, []() {
-        server.send_P(200, "text/html", index_html);
-    });
-    
-    server.on("/transmit", HTTP_GET, []() {
-        server.send_P(200, "text/html", transmit_html);
-    });
-    
-    server.on("/graph", HTTP_GET, []() {
-        server.send_P(200, "text/html", graph_html);
-    });
-
-    server.on("/graph-view", HTTP_GET, []() {
-        server.send_P(200, "text/html", graph_viewer_html);
-    });
-
-    server.on("/download", HTTP_GET, []() {
-        if (server.hasArg("file")) {
-            String filename = "/" + server.arg("file");
-            
-            if (SD.exists(filename)) {
-                File file = SD.open(filename, FILE_READ);
-                if (file) {
-                    String displayName = server.arg("file");
-                    
-                    server.sendHeader("Content-Disposition", 
-                        "attachment; filename=\"" + displayName + "\"");
-                    server.sendHeader("Content-Type", "application/octet-stream");
-                    
-                    server.streamFile(file, "application/octet-stream");
-                    file.close();
-                } else {
-                    server.send(500, "text/plain", "Failed to open file");
-                }
-            } else {
-                server.send(404, "text/plain", "File not found");
-            }
-        } else {
-            server.send(400, "text/plain", "Bad request");
-        }
-    });
-    server.begin();
-    
-    canQueue = xQueueCreate(CAN_QUEUE_SIZE, sizeof(CANMessage));
-    sdMutex = xSemaphoreCreateMutex();
-    
-    if (canQueue == NULL || sdMutex == NULL) {
-        Serial.println("✗ RTOS 객체 생성 실패!");
-        while (1) delay(1000);
-    }
-    
-    attachInterrupt(digitalPinToInterrupt(CAN_INT_PIN), canISR, FALLING);
-    
-    xTaskCreatePinnedToCore(canRxTask, "CAN_RX", 4096, NULL, 4, &canRxTaskHandle, 1);
-    xTaskCreatePinnedToCore(sdWriteTask, "SD_WRITE", 12288, NULL, 3, &sdWriteTaskHandle, 1);
-    xTaskCreatePinnedToCore(sdMonitorTask, "SD_MONITOR", 4096, NULL, 1, NULL, 0);
-    xTaskCreatePinnedToCore(webUpdateTask, "WEB_UPDATE", 8192, NULL, 2, &webTaskHandle, 0);
-    
-    Serial.println("✓ 모든 태스크 시작 완료");
-    Serial.println("\n========================================");
-    Serial.println("  웹 인터페이스 접속");
-    Serial.println("========================================");
-    Serial.println("  1. WiFi: Byun_CAN_Logger (12345678)");
-    Serial.print("  2. http://");
-    Serial.println(WiFi.softAPIP());
-    Serial.println("  3. Pages:");
-    Serial.println("     - Monitor:  /");
-    Serial.println("     - Transmit: /transmit");
-    Serial.println("     - Graph:    /graph");
-    Serial.println("========================================\n");
-    Serial.println("⚠️  시간 동기화를 위해 웹페이지에서 '⏰ 시간 동기화' 버튼을 클릭하세요");
-}
-
-void loop() {
-    server.handleClient();
-    vTaskDelay(pdMS_TO_TICKS(10));
-    
-    static uint32_t lastPrint = 0;
-    if (millis() - lastPrint > 10000) {
-        Serial.printf("[상태] 큐: %d/%d | 로깅: %s | SD: %s | RX: %lu | TX: %lu | 시간동기: %s\n",
-            uxQueueMessagesWaiting(canQueue), CAN_QUEUE_SIZE,
-            loggingEnabled ? "ON " : "OFF",
-            sdCardReady ? "OK" : "NO",
-            totalMsgCount, totalTxCount,
-            timeSyncStatus.synchronized ? "OK" : "NO");
-        lastPrint = millis();
-    }
+/*
+ * Byun CAN Logger with Web Interface + RTC DS3231
+ * Version: 1.3
+ */
+
+#include <Arduino.h>
+#include <SPI.h>
+#include <mcp2515.h>
+#include <SD.h>
+#include <WiFi.h>
+#include <WebServer.h>
+#include <WebSocketsServer.h>
+#include <freertos/FreeRTOS.h>
+#include <freertos/task.h>
+#include <freertos/queue.h>
+#include <freertos/semphr.h>
+#include <sys/time.h>
+#include <time.h>
+#include <Wire.h>
+#include <RTClib.h>
+#include "index.h"
+#include "transmit.h"
+#include "graph.h"
+#include "graph_viewer.h"
+
+
+// GPIO 핀 정의
+#define CAN_INT_PIN 27
+
+// HSPI 핀 (CAN)
+#define HSPI_MISO 12
+#define HSPI_MOSI 13
+#define HSPI_SCLK 14
+#define HSPI_CS 15
+
+// VSPI 핀 (SD Card)
+#define VSPI_MISO 19
+#define VSPI_MOSI 23
+#define VSPI_SCLK 18
+#define VSPI_CS 5
+
+// I2C 핀 (RTC DS3231)
+#define I2C_SDA 25
+#define I2C_SCL 26
+
+// 버퍼 설정
+#define CAN_QUEUE_SIZE 1000
+#define FILE_BUFFER_SIZE 8192
+#define MAX_FILENAME_LEN 64
+#define RECENT_MSG_COUNT 100
+#define MAX_TX_MESSAGES 20
+
+// CAN 메시지 구조체 - 마이크로초 단위 타임스탬프
+struct CANMessage {
+    uint64_t timestamp_us;  // 마이크로초 단위 Unix timestamp
+    uint32_t id;
+    uint8_t dlc;
+    uint8_t data[8];
+} __attribute__((packed));
+
+// 실시간 모니터링용 구조체
+struct RecentCANData {
+    CANMessage msg;
+    uint32_t count;
+};
+
+// CAN 송신용 구조체
+struct TxMessage {
+    uint32_t id;
+    bool extended;
+    uint8_t dlc;
+    uint8_t data[8];
+    uint32_t interval;
+    uint32_t lastSent;
+    bool active;
+};
+
+// 시간 동기화 상태
+struct TimeSyncStatus {
+    bool synchronized;
+    uint64_t lastSyncTime;
+    int32_t offsetUs;
+    uint32_t syncCount;
+    bool rtcAvailable;
+} timeSyncStatus = {false, 0, 0, 0, false};
+
+// WiFi AP 설정
+const char* ssid = "Byun_CAN_Logger";
+const char* password = "12345678";
+
+// 전역 변수
+SPIClass hspi(HSPI);
+SPIClass vspi(VSPI);
+MCP2515 mcp2515(HSPI_CS, 10000000, &hspi);
+RTC_DS3231 rtc;
+
+WebServer server(80);
+WebSocketsServer webSocket = WebSocketsServer(81);
+
+QueueHandle_t canQueue;
+SemaphoreHandle_t sdMutex;
+TaskHandle_t canRxTaskHandle = NULL;
+TaskHandle_t sdWriteTaskHandle = NULL;
+TaskHandle_t webTaskHandle = NULL;
+
+volatile bool loggingEnabled = false;
+volatile bool sdCardReady = false;
+File logFile;
+char currentFilename[MAX_FILENAME_LEN];
+uint8_t fileBuffer[FILE_BUFFER_SIZE];
+uint16_t bufferIndex = 0;
+
+// CAN 속도 설정
+CAN_SPEED currentCanSpeed = CAN_1000KBPS;
+const char* canSpeedNames[] = {"125K", "250K", "500K", "1M"};
+CAN_SPEED canSpeedValues[] = {CAN_125KBPS, CAN_250KBPS, CAN_500KBPS, CAN_1000KBPS};
+
+// 실시간 모니터링용
+RecentCANData recentData[RECENT_MSG_COUNT];
+uint32_t totalMsgCount = 0;
+uint32_t msgPerSecond = 0;
+uint32_t lastMsgCountTime = 0;
+uint32_t lastMsgCount = 0;
+
+// CAN 송신용
+TxMessage txMessages[MAX_TX_MESSAGES];
+uint32_t totalTxCount = 0;
+
+// 정밀한 현재 시간 가져오기 (마이크로초)
+uint64_t getMicrosecondTimestamp() {
+    struct timeval tv;
+    gettimeofday(&tv, NULL);
+    return (uint64_t)tv.tv_sec * 1000000ULL + (uint64_t)tv.tv_usec;
+}
+
+// RTC에서 시간 읽기
+String getRTCTime() {
+    if (!timeSyncStatus.rtcAvailable) {
+        return "RTC not available";
+    }
+    
+    DateTime now = rtc.now();
+    char timeStr[32];
+    snprintf(timeStr, sizeof(timeStr), "%04d-%02d-%02d %02d:%02d:%02d",
+             now.year(), now.month(), now.day(),
+             now.hour(), now.minute(), now.second());
+    return String(timeStr);
+}
+
+// RTC에 시간 설정
+bool setRTCTime(uint64_t timestampMs) {
+    if (!timeSyncStatus.rtcAvailable) {
+        Serial.println("❌ RTC not available");
+        return false;
+    }
+    
+    time_t timestamp = timestampMs / 1000;
+    DateTime dt(timestamp);
+    rtc.adjust(dt);
+    
+    Serial.printf("⏰ RTC 시간 설정: %s\n", getRTCTime().c_str());
+    return true;
+}
+
+// RTC에서 시스템 시간 동기화
+bool syncTimeFromRTC() {
+    if (!timeSyncStatus.rtcAvailable) {
+        Serial.println("❌ RTC not available");
+        return false;
+    }
+    
+    DateTime now = rtc.now();
+    struct timeval tv;
+    tv.tv_sec = now.unixtime();
+    tv.tv_usec = 0;
+    settimeofday(&tv, NULL);
+    
+    timeSyncStatus.synchronized = true;
+    timeSyncStatus.lastSyncTime = getMicrosecondTimestamp();
+    timeSyncStatus.syncCount++;
+    
+    char timeStr[64];
+    strftime(timeStr, sizeof(timeStr), "%Y-%m-%d %H:%M:%S", localtime(&tv.tv_sec));
+    
+    Serial.printf("⏰ RTC로부터 시간 동기화: %s (동기화 횟수: %u)\n", 
+                  timeStr, timeSyncStatus.syncCount);
+    return true;
+}
+
+// 시간 동기화 설정 (웹에서)
+void setSystemTime(uint64_t timestampMs) {
+    struct timeval tv;
+    tv.tv_sec = timestampMs / 1000;
+    tv.tv_usec = (timestampMs % 1000) * 1000;
+    settimeofday(&tv, NULL);
+    
+    timeSyncStatus.synchronized = true;
+    timeSyncStatus.lastSyncTime = getMicrosecondTimestamp();
+    timeSyncStatus.syncCount++;
+    
+    // 현재 시간 출력
+    time_t now = tv.tv_sec;
+    struct tm timeinfo;
+    localtime_r(&now, &timeinfo);
+    char timeStr[64];
+    strftime(timeStr, sizeof(timeStr), "%Y-%m-%d %H:%M:%S", &timeinfo);
+    
+    Serial.printf("⏰ 웹에서 시간 동기화: %s.%03d (동기화 횟수: %u)\n", 
+                  timeStr, (int)(tv.tv_usec / 1000), timeSyncStatus.syncCount);
+}
+
+// 함수 선언
+void changeCanSpeed(CAN_SPEED newSpeed);
+bool createNewLogFile();
+bool flushBuffer();
+void startLogging();
+void stopLogging();
+void canRxTask(void *pvParameters);
+void sdWriteTask(void *pvParameters);
+void sdMonitorTask(void *pvParameters);
+void sendFileList(uint8_t clientNum);
+void webSocketEvent(uint8_t num, WStype_t type, uint8_t * payload, size_t length);
+void handleCanTransmit(String msg);
+void handleStartMessage(String msg);
+void handleStopMessage(String msg);
+void handleTimeSync(String msg);
+void handleRTCGet(uint8_t clientNum);
+void handleRTCSet(String msg);
+void webUpdateTask(void *pvParameters);
+
+// CAN 인터럽트 핸들러
+void IRAM_ATTR canISR() {
+    BaseType_t xHigherPriorityTaskWoken = pdFALSE;
+    if (canRxTaskHandle != NULL) {
+        vTaskNotifyGiveFromISR(canRxTaskHandle, &xHigherPriorityTaskWoken);
+        portYIELD_FROM_ISR(xHigherPriorityTaskWoken);
+    }
+}
+
+// CAN 속도 변경
+void changeCanSpeed(CAN_SPEED newSpeed) {
+    detachInterrupt(digitalPinToInterrupt(CAN_INT_PIN));
+    mcp2515.reset();
+    mcp2515.setBitrate(newSpeed, MCP_8MHZ);
+    mcp2515.setNormalMode();
+    currentCanSpeed = newSpeed;
+    attachInterrupt(digitalPinToInterrupt(CAN_INT_PIN), canISR, FALLING);
+    Serial.printf("CAN 속도 변경: %s\n", canSpeedNames[newSpeed]);
+}
+
+// 새 로그 파일 생성 - 시간 기반 파일명
+bool createNewLogFile() {
+    if (logFile) {
+        logFile.flush();
+        logFile.close();
+        vTaskDelay(pdMS_TO_TICKS(10));
+    }
+    
+    // 현재 시간으로 파일명 생성
+    time_t now;
+    struct tm timeinfo;
+    time(&now);
+    localtime_r(&now, &timeinfo);
+    
+    char filename[MAX_FILENAME_LEN];
+    snprintf(filename, MAX_FILENAME_LEN, "/canlog_%04d%02d%02d_%02d%02d%02d.bin",
+             timeinfo.tm_year + 1900, 
+             timeinfo.tm_mon + 1, 
+             timeinfo.tm_mday,
+             timeinfo.tm_hour, 
+             timeinfo.tm_min, 
+             timeinfo.tm_sec);
+    
+    logFile = SD.open(filename, FILE_WRITE);
+    
+    if (!logFile) {
+        Serial.printf("파일 생성 실패: %s\n", filename);
+        return false;
+    }
+    
+    strncpy(currentFilename, filename, MAX_FILENAME_LEN);
+    Serial.printf("새 로그 파일 생성: %s\n", currentFilename);
+    
+    // 시간 동기화 경고
+    if (!timeSyncStatus.synchronized) {
+        Serial.println("⚠️ 경고: 시간이 동기화되지 않았습니다! 웹페이지에서 시간 동기화를 실행하세요.");
+    }
+    
+    return true;
+}
+
+// 버퍼 플러시
+bool flushBuffer() {
+    if (bufferIndex == 0) return true;
+    
+    if (xSemaphoreTake(sdMutex, portMAX_DELAY) == pdTRUE) {
+        if (logFile) {
+            size_t written = logFile.write(fileBuffer, bufferIndex);
+            logFile.flush();
+            xSemaphoreGive(sdMutex);
+            
+            if (written != bufferIndex) {
+                Serial.println("SD 쓰기 오류!");
+                return false;
+            }
+            bufferIndex = 0;
+            return true;
+        }
+        xSemaphoreGive(sdMutex);
+    }
+    return false;
+}
+
+// 로깅 시작
+void startLogging() {
+    if (loggingEnabled) {
+        Serial.println("이미 로깅 중");
+        return;
+    }
+    
+    if (!sdCardReady) {
+        Serial.println("SD 카드가 준비되지 않음");
+        return;
+    }
+    
+    Serial.println("로깅 시작");
+    
+    if (xSemaphoreTake(sdMutex, pdMS_TO_TICKS(1000)) == pdTRUE) {
+        if (createNewLogFile()) {
+            loggingEnabled = true;
+            bufferIndex = 0;
+        }
+        xSemaphoreGive(sdMutex);
+    }
+}
+
+// 로깅 중지
+void stopLogging() {
+    if (!loggingEnabled) {
+        Serial.println("로깅이 실행 중이 아님");
+        return;
+    }
+    
+    Serial.println("로깅 정지");
+    loggingEnabled = false;
+    
+    flushBuffer();
+    
+    if (xSemaphoreTake(sdMutex, pdMS_TO_TICKS(1000)) == pdTRUE) {
+        if (logFile) {
+            logFile.close();
+        }
+        xSemaphoreGive(sdMutex);
+    }
+}
+
+// CAN 수신 태스크
+void canRxTask(void *pvParameters) {
+    struct can_frame frame;
+    CANMessage msg;
+    
+    Serial.println("CAN 수신 태스크 시작");
+    
+    while (1) {
+        ulTaskNotifyTake(pdTRUE, portMAX_DELAY);
+        
+        while (mcp2515.readMessage(&frame) == MCP2515::ERROR_OK) {
+            // 마이크로초 단위 타임스탬프
+            msg.timestamp_us = getMicrosecondTimestamp();
+            msg.id = frame.can_id;
+            msg.dlc = frame.can_dlc;
+            memcpy(msg.data, frame.data, 8);
+            
+            if (xQueueSend(canQueue, &msg, 0) != pdTRUE) {
+                static uint32_t lastWarning = 0;
+                if (millis() - lastWarning > 1000) {
+                    Serial.println("경고: CAN 큐 오버플로우!");
+                    lastWarning = millis();
+                }
+            }
+            
+            // 최근 메시지 저장 및 카운트 증가
+            bool found = false;
+            for (int i = 0; i < RECENT_MSG_COUNT; i++) {
+                if (recentData[i].msg.id == msg.id && recentData[i].msg.timestamp_us > 0) {
+                    recentData[i].msg = msg;
+                    recentData[i].count++;
+                    found = true;
+                    break;
+                }
+            }
+            
+            if (!found) {
+                for (int i = 0; i < RECENT_MSG_COUNT; i++) {
+                    if (recentData[i].msg.timestamp_us == 0) {
+                        recentData[i].msg = msg;
+                        recentData[i].count = 1;
+                        found = true;
+                        break;
+                    }
+                }
+                
+                if (!found) {
+                    static int replaceIndex = 0;
+                    recentData[replaceIndex].msg = msg;
+                    recentData[replaceIndex].count = 1;
+                    replaceIndex = (replaceIndex + 1) % RECENT_MSG_COUNT;
+                }
+            }
+            
+            totalMsgCount++;
+        }
+    }
+}
+
+// SD 쓰기 태스크
+void sdWriteTask(void *pvParameters) {
+    CANMessage msg;
+    
+    Serial.println("SD 쓰기 태스크 시작");
+    
+    while (1) {
+        if (xQueueReceive(canQueue, &msg, pdMS_TO_TICKS(100)) == pdTRUE) {
+            
+            if (loggingEnabled && sdCardReady) {
+                if (bufferIndex + sizeof(CANMessage) > FILE_BUFFER_SIZE) {
+                    if (!flushBuffer()) {
+                        continue;
+                    }
+                }
+                
+                memcpy(&fileBuffer[bufferIndex], &msg, sizeof(CANMessage));
+                bufferIndex += sizeof(CANMessage);
+            }
+        } else {
+            if (loggingEnabled && bufferIndex > 0) {
+                flushBuffer();
+            }
+        }
+    }
+}
+
+// SD 모니터 태스크
+void sdMonitorTask(void *pvParameters) {
+    Serial.println("SD 모니터 태스크 시작");
+    
+    while (1) {
+        bool cardPresent = SD.begin(VSPI_CS, vspi);
+        
+        if (cardPresent != sdCardReady) {
+            sdCardReady = cardPresent;
+            
+            if (sdCardReady) {
+                Serial.println("SD 카드 준비됨");
+            } else {
+                Serial.println("SD 카드 없음");
+                if (loggingEnabled) {
+                    stopLogging();
+                }
+            }
+        }
+        
+        vTaskDelay(pdMS_TO_TICKS(1000));
+    }
+}
+
+// 파일 목록 전송
+void sendFileList(uint8_t clientNum) {
+    String fileList = "{\"type\":\"files\",\"files\":[";
+    
+    if (!sdCardReady) {
+        fileList += "],\"error\":\"SD card not ready\"}";
+        webSocket.sendTXT(clientNum, fileList);
+        return;
+    }
+    
+    File root = SD.open("/");
+    if (!root) {
+        fileList += "],\"error\":\"Cannot open root directory\"}";
+        webSocket.sendTXT(clientNum, fileList);
+        return;
+    }
+    
+    File file = root.openNextFile();
+    bool first = true;
+    int fileCount = 0;
+    
+    while (file) {
+        if (!file.isDirectory()) {
+            String name = file.name();
+            if (name.startsWith("/")) name = name.substring(1);
+            
+            if (name.endsWith(".bin") || name.endsWith(".BIN")) {
+                if (!first) fileList += ",";
+                fileList += "{\"name\":\"" + name + "\",\"size\":" + String(file.size()) + "}";
+                first = false;
+                fileCount++;
+            }
+        }
+        file.close();
+        file = root.openNextFile();
+    }
+    root.close();
+    
+    fileList += "]}";
+    webSocket.sendTXT(clientNum, fileList);
+    
+    Serial.printf("파일 목록 전송: %d개\n", fileCount);
+}
+
+// CAN 메시지 전송 처리
+void handleCanTransmit(String msg) {
+    int idIdx = msg.indexOf("\"id\":\"") + 6;
+    int idEnd = msg.indexOf("\"", idIdx);
+    String idStr = msg.substring(idIdx, idEnd);
+    
+    int typeIdx = msg.indexOf("\"type\":\"") + 8;
+    String typeStr = msg.substring(typeIdx, typeIdx + 3);
+    bool extended = (typeStr == "ext");
+    
+    int dlcIdx = msg.indexOf("\"dlc\":") + 6;
+    int dlc = msg.substring(dlcIdx, dlcIdx + 1).toInt();
+    
+    int dataIdx = msg.indexOf("\"data\":\"") + 8;
+    String dataStr = msg.substring(dataIdx, dataIdx + 16);
+    
+    uint32_t canId = strtoul(idStr.c_str(), NULL, 16);
+    
+    uint8_t data[8] = {0};
+    for (int i = 0; i < dlc && i < 8; i++) {
+        String byteStr = dataStr.substring(i * 2, i * 2 + 2);
+        data[i] = strtoul(byteStr.c_str(), NULL, 16);
+    }
+    
+    struct can_frame frame;
+    frame.can_id = canId;
+    if (extended) frame.can_id |= CAN_EFF_FLAG;
+    frame.can_dlc = dlc;
+    memcpy(frame.data, data, 8);
+    
+    if (mcp2515.sendMessage(&frame) == MCP2515::ERROR_OK) {
+        totalTxCount++;
+        Serial.printf("CAN TX: 0x%X [%d]\n", canId, dlc);
+    }
+}
+
+// 주기 전송 시작
+void handleStartMessage(String msg) {
+    int indexIdx = msg.indexOf("\"index\":") + 8;
+    int index = msg.substring(indexIdx, indexIdx + 2).toInt();
+    
+    if (index >= 0 && index < MAX_TX_MESSAGES) {
+        int idIdx = msg.indexOf("\"id\":\"") + 6;
+        int idEnd = msg.indexOf("\"", idIdx);
+        String idStr = msg.substring(idIdx, idEnd);
+        
+        int typeIdx = msg.indexOf("\"type\":\"") + 8;
+        String typeStr = msg.substring(typeIdx, typeIdx + 3);
+        
+        int dlcIdx = msg.indexOf("\"dlc\":") + 6;
+        int dlc = msg.substring(dlcIdx, dlcIdx + 1).toInt();
+        
+        int dataIdx = msg.indexOf("\"data\":\"") + 8;
+        String dataStr = msg.substring(dataIdx, dataIdx + 16);
+        
+        int intervalIdx = msg.indexOf("\"interval\":") + 11;
+        int interval = msg.substring(intervalIdx, intervalIdx + 5).toInt();
+        
+        txMessages[index].id = strtoul(idStr.c_str(), NULL, 16);
+        txMessages[index].extended = (typeStr == "ext");
+        txMessages[index].dlc = dlc;
+        
+        for (int i = 0; i < 8; i++) {
+            String byteStr = dataStr.substring(i * 2, i * 2 + 2);
+            txMessages[index].data[i] = strtoul(byteStr.c_str(), NULL, 16);
+        }
+        
+        txMessages[index].interval = interval;
+        txMessages[index].lastSent = 0;
+        txMessages[index].active = true;
+        
+        Serial.printf("주기 전송 시작 [%d]: 0x%X\n", index, txMessages[index].id);
+    }
+}
+
+// 주기 전송 중지
+void handleStopMessage(String msg) {
+    int indexIdx = msg.indexOf("\"index\":") + 8;
+    int index = msg.substring(indexIdx, indexIdx + 2).toInt();
+    
+    if (index >= 0 && index < MAX_TX_MESSAGES) {
+        txMessages[index].active = false;
+        Serial.printf("주기 전송 중지 [%d]\n", index);
+    }
+}
+
+// 시간 동기화 처리 (웹에서)
+void handleTimeSync(String msg) {
+    int timestampIdx = msg.indexOf("\"timestamp\":") + 12;
+    String timestampStr = msg.substring(timestampIdx);
+    timestampStr = timestampStr.substring(0, timestampStr.indexOf("}"));
+    
+    uint64_t clientTimestamp = strtoull(timestampStr.c_str(), NULL, 10);
+    
+    if (clientTimestamp > 0) {
+        setSystemTime(clientTimestamp);
+    }
+}
+
+// RTC 시간 읽기
+void handleRTCGet(uint8_t clientNum) {
+    String response = "{\"type\":\"rtcTime\",\"time\":\"";
+    response += getRTCTime();
+    response += "\",\"available\":";
+    response += timeSyncStatus.rtcAvailable ? "true" : "false";
+    response += "}";
+    
+    webSocket.sendTXT(clientNum, response);
+}
+
+// RTC 시간 설정
+void handleRTCSet(String msg) {
+    int timestampIdx = msg.indexOf("\"timestamp\":") + 12;
+    String timestampStr = msg.substring(timestampIdx);
+    timestampStr = timestampStr.substring(0, timestampStr.indexOf("}"));
+    
+    uint64_t timestamp = strtoull(timestampStr.c_str(), NULL, 10);
+    
+    if (timestamp > 0) {
+        setRTCTime(timestamp);
+        // RTC 설정 후 시스템 시간도 동기화
+        syncTimeFromRTC();
+    }
+}
+
+// 웹소켓 이벤트 핸들러
+void webSocketEvent(uint8_t num, WStype_t type, uint8_t * payload, size_t length) {
+    switch(type) {
+        case WStype_DISCONNECTED:
+            Serial.printf("WebSocket #%u 연결 해제\n", num);
+            break;
+            
+        case WStype_CONNECTED:
+            {
+                IPAddress ip = webSocket.remoteIP(num);
+                Serial.printf("WebSocket #%u 연결: %d.%d.%d.%d\n", 
+                    num, ip[0], ip[1], ip[2], ip[3]);
+                sendFileList(num);
+                
+                // 시간 동기화 상태 전송
+                String syncStatus = "{\"type\":\"timeSyncStatus\",\"synchronized\":";
+                syncStatus += timeSyncStatus.synchronized ? "true" : "false";
+                syncStatus += ",\"syncCount\":" + String(timeSyncStatus.syncCount);
+                syncStatus += ",\"rtcAvailable\":";
+                syncStatus += timeSyncStatus.rtcAvailable ? "true" : "false";
+                syncStatus += "}";
+                webSocket.sendTXT(num, syncStatus);
+                
+                // RTC 시간 전송
+                handleRTCGet(num);
+            }
+            break;
+            
+        case WStype_TEXT:
+            {
+                String msg = String((char*)payload);
+                
+                if (msg.indexOf("\"cmd\":\"setSpeed\"") >= 0) {
+                    int speedIdx = msg.indexOf("\"speed\":") + 8;
+                    int speed = msg.substring(speedIdx, speedIdx + 1).toInt();
+                    
+                    if (speed >= 0 && speed < 4) {
+                        changeCanSpeed(canSpeedValues[speed]);
+                    }
+                } 
+                else if (msg.indexOf("\"cmd\":\"getFiles\"") >= 0) {
+                    sendFileList(num);
+                }
+                else if (msg.indexOf("\"cmd\":\"startLogging\"") >= 0) {
+                    startLogging();
+                }
+                else if (msg.indexOf("\"cmd\":\"stopLogging\"") >= 0) {
+                    stopLogging();
+                }
+                else if (msg.indexOf("\"cmd\":\"sendCan\"") >= 0) {
+                    handleCanTransmit(msg);
+                }
+                else if (msg.indexOf("\"cmd\":\"startMsg\"") >= 0) {
+                    handleStartMessage(msg);
+                }
+                else if (msg.indexOf("\"cmd\":\"stopMsg\"") >= 0) {
+                    handleStopMessage(msg);
+                }
+                else if (msg.indexOf("\"cmd\":\"stopAll\"") >= 0) {
+                    for (int i = 0; i < MAX_TX_MESSAGES; i++) {
+                        txMessages[i].active = false;
+                    }
+                }
+                else if (msg.indexOf("\"cmd\":\"syncTime\"") >= 0) {
+                    handleTimeSync(msg);
+                }
+                else if (msg.indexOf("\"cmd\":\"getRTC\"") >= 0) {
+                    handleRTCGet(num);
+                }
+                else if (msg.indexOf("\"cmd\":\"setRTC\"") >= 0) {
+                    handleRTCSet(msg);
+                }
+                else if (msg.indexOf("\"cmd\":\"syncFromRTC\"") >= 0) {
+                    syncTimeFromRTC();
+                }
+            }
+            break;
+    }
+}
+
+// 웹 업데이트 태스크
+void webUpdateTask(void *pvParameters) {
+    uint32_t lastStatusUpdate = 0;
+    uint32_t lastCanUpdate = 0;
+    uint32_t lastTxStatusUpdate = 0;
+    const uint32_t CAN_UPDATE_INTERVAL = 500;
+    
+    Serial.println("웹 업데이트 태스크 시작");
+    
+    while (1) {
+        uint32_t now = millis();
+        
+        webSocket.loop();
+        
+        // 주기 전송 처리
+        for (int i = 0; i < MAX_TX_MESSAGES; i++) {
+            if (txMessages[i].active && (now - txMessages[i].lastSent >= txMessages[i].interval)) {
+                struct can_frame frame;
+                frame.can_id = txMessages[i].id;
+                if (txMessages[i].extended) frame.can_id |= CAN_EFF_FLAG;
+                frame.can_dlc = txMessages[i].dlc;
+                memcpy(frame.data, txMessages[i].data, 8);
+                
+                if (mcp2515.sendMessage(&frame) == MCP2515::ERROR_OK) {
+                    totalTxCount++;
+                    txMessages[i].lastSent = now;
+                }
+            }
+        }
+        
+        // TX 상태 업데이트
+        if (now - lastTxStatusUpdate >= 1000) {
+            String txStatus = "{\"type\":\"txStatus\",\"count\":" + String(totalTxCount) + "}";
+            webSocket.broadcastTXT(txStatus);
+            lastTxStatusUpdate = now;
+        }
+        
+        // 상태 업데이트
+        if (now - lastStatusUpdate >= 1000) {
+            if (now - lastMsgCountTime >= 1000) {
+                msgPerSecond = totalMsgCount - lastMsgCount;
+                lastMsgCount = totalMsgCount;
+                lastMsgCountTime = now;
+            }
+            
+            String status = "{\"type\":\"status\",";
+            status += "\"logging\":" + String(loggingEnabled ? "true" : "false") + ",";
+            status += "\"sdReady\":" + String(sdCardReady ? "true" : "false") + ",";
+            status += "\"msgCount\":" + String(totalMsgCount) + ",";
+            status += "\"msgSpeed\":" + String(msgPerSecond) + ",";
+            status += "\"timeSync\":" + String(timeSyncStatus.synchronized ? "true" : "false") + ",";
+            status += "\"syncCount\":" + String(timeSyncStatus.syncCount) + ",";
+            status += "\"rtcAvailable\":" + String(timeSyncStatus.rtcAvailable ? "true" : "false") + ",";
+            
+            if (loggingEnabled && logFile) {
+                status += "\"currentFile\":\"" + String(currentFilename) + "\"";
+            } else {
+                status += "\"currentFile\":\"\"";
+            }
+            status += "}";
+            
+            webSocket.broadcastTXT(status);
+            lastStatusUpdate = now;
+        }
+        
+        // CAN 메시지 일괄 업데이트
+        if (now - lastCanUpdate >= CAN_UPDATE_INTERVAL) {
+            String canBatch = "{\"type\":\"canBatch\",\"messages\":[";
+            bool first = true;
+            
+            for (int i = 0; i < RECENT_MSG_COUNT; i++) {
+                if (recentData[i].msg.timestamp_us > 0) {
+                    CANMessage* msg = &recentData[i].msg;
+                    
+                    if (!first) canBatch += ",";
+                    first = false;
+                    
+                    canBatch += "{\"id\":\"";
+                    if (msg->id < 0x10) canBatch += "0";
+                    if (msg->id < 0x100) canBatch += "0";
+                    if (msg->id < 0x1000) canBatch += "0";
+                    canBatch += String(msg->id, HEX);
+                    canBatch += "\",\"dlc\":" + String(msg->dlc);
+                    canBatch += ",\"data\":\"";
+                    
+                    for (int j = 0; j < msg->dlc; j++) {
+                        if (msg->data[j] < 0x10) canBatch += "0";
+                        canBatch += String(msg->data[j], HEX);
+                        if (j < msg->dlc - 1) canBatch += " ";
+                    }
+                    
+                    // 마이크로초 타임스탬프를 밀리초로 변환하여 전송
+                    uint64_t timestamp_ms = msg->timestamp_us / 1000;
+                    canBatch += "\",\"timestamp\":" + String((uint32_t)timestamp_ms);
+                    canBatch += ",\"count\":" + String(recentData[i].count) + "}";
+                }
+            }
+            
+            canBatch += "]}";
+            
+            if (!first) {
+                webSocket.broadcastTXT(canBatch);
+            }
+            
+            lastCanUpdate = now;
+        }
+        
+        vTaskDelay(pdMS_TO_TICKS(50));
+    }
+}
+
+void setup() {
+    Serial.begin(115200);
+    delay(1000);
+    Serial.println("\n========================================");
+    Serial.println("  ESP32 CAN Logger with RTC DS3231  ");
+    Serial.println("========================================");
+    
+    memset(recentData, 0, sizeof(recentData));
+    memset(txMessages, 0, sizeof(txMessages));
+    
+    // I2C 초기화 (RTC)
+    Wire.begin(I2C_SDA, I2C_SCL);
+    
+    // RTC 초기화
+    if (rtc.begin(&Wire)) {
+        Serial.println("✓ RTC DS3231 초기화 완료");
+        timeSyncStatus.rtcAvailable = true;
+        
+        // RTC 손실 확인
+        if (rtc.lostPower()) {
+            Serial.println("⚠️ RTC 전원 손실 감지 - 시간 설정 필요");
+        } else {
+            Serial.printf("✓ RTC 시간: %s\n", getRTCTime().c_str());
+            // RTC에서 시스템 시간 동기화
+            syncTimeFromRTC();
+        }
+    } else {
+        Serial.println("✗ RTC DS3231 초기화 실패");
+        timeSyncStatus.rtcAvailable = false;
+    }
+    
+    pinMode(CAN_INT_PIN, INPUT_PULLUP);
+    
+    hspi.begin(HSPI_SCLK, HSPI_MISO, HSPI_MOSI, HSPI_CS);
+    vspi.begin(VSPI_SCLK, VSPI_MISO, VSPI_MOSI, VSPI_CS);
+    
+    mcp2515.reset();
+    mcp2515.setBitrate(CAN_1000KBPS, MCP_8MHZ);
+    mcp2515.setNormalMode();
+    Serial.println("✓ MCP2515 초기화 완료");
+    
+    if (SD.begin(VSPI_CS, vspi)) {
+        sdCardReady = true;
+        Serial.println("✓ SD 카드 초기화 완료");
+    } else {
+        Serial.println("✗ SD 카드 초기화 실패");
+    }
+    
+    WiFi.softAP(ssid, password);
+    Serial.print("✓ AP IP: ");
+    Serial.println(WiFi.softAPIP());
+    
+    webSocket.begin();
+    webSocket.onEvent(webSocketEvent);
+    
+    server.on("/", HTTP_GET, []() {
+        server.send_P(200, "text/html", index_html);
+    });
+    
+    server.on("/transmit", HTTP_GET, []() {
+        server.send_P(200, "text/html", transmit_html);
+    });
+    
+    server.on("/graph", HTTP_GET, []() {
+        server.send_P(200, "text/html", graph_html);
+    });
+
+    server.on("/graph-view", HTTP_GET, []() {
+        server.send_P(200, "text/html", graph_viewer_html);
+    });
+
+    server.on("/download", HTTP_GET, []() {
+        if (server.hasArg("file")) {
+            String filename = "/" + server.arg("file");
+            
+            if (SD.exists(filename)) {
+                File file = SD.open(filename, FILE_READ);
+                if (file) {
+                    String displayName = server.arg("file");
+                    
+                    server.sendHeader("Content-Disposition", 
+                        "attachment; filename=\"" + displayName + "\"");
+                    server.sendHeader("Content-Type", "application/octet-stream");
+                    
+                    server.streamFile(file, "application/octet-stream");
+                    file.close();
+                } else {
+                    server.send(500, "text/plain", "Failed to open file");
+                }
+            } else {
+                server.send(404, "text/plain", "File not found");
+            }
+        } else {
+            server.send(400, "text/plain", "Bad request");
+        }
+    });
+    server.begin();
+    
+    canQueue = xQueueCreate(CAN_QUEUE_SIZE, sizeof(CANMessage));
+    sdMutex = xSemaphoreCreateMutex();
+    
+    if (canQueue == NULL || sdMutex == NULL) {
+        Serial.println("✗ RTOS 객체 생성 실패!");
+        while (1) delay(1000);
+    }
+    
+    attachInterrupt(digitalPinToInterrupt(CAN_INT_PIN), canISR, FALLING);
+    
+    xTaskCreatePinnedToCore(canRxTask, "CAN_RX", 4096, NULL, 4, &canRxTaskHandle, 1);
+    xTaskCreatePinnedToCore(sdWriteTask, "SD_WRITE", 12288, NULL, 3, &sdWriteTaskHandle, 1);
+    xTaskCreatePinnedToCore(sdMonitorTask, "SD_MONITOR", 4096, NULL, 1, NULL, 0);
+    xTaskCreatePinnedToCore(webUpdateTask, "WEB_UPDATE", 8192, NULL, 2, &webTaskHandle, 0);
+    
+    Serial.println("✓ 모든 태스크 시작 완료");
+    Serial.println("\n========================================");
+    Serial.println("  웹 인터페이스 접속");
+    Serial.println("========================================");
+    Serial.println("  1. WiFi: Byun_CAN_Logger (12345678)");
+    Serial.print("  2. http://");
+    Serial.println(WiFi.softAPIP());
+    Serial.println("  3. Pages:");
+    Serial.println("     - Monitor:  /");
+    Serial.println("     - Transmit: /transmit");
+    Serial.println("     - Graph:    /graph");
+    Serial.println("========================================\n");
+    
+    if (timeSyncStatus.rtcAvailable) {
+        Serial.println("✓ RTC 사용 가능 - 웹페이지에서 RTC 시간 관리 가능");
+    } else {
+        Serial.println("⚠️ RTC 사용 불가 - 웹페이지에서 시간 동기화 필요");
+    }
+}
+
+void loop() {
+    server.handleClient();
+    vTaskDelay(pdMS_TO_TICKS(10));
+    
+    static uint32_t lastPrint = 0;
+    if (millis() - lastPrint > 10000) {
+        Serial.printf("[상태] 큐: %d/%d | 로깅: %s | SD: %s | RX: %lu | TX: %lu | 시간동기: %s | RTC: %s\n",
+            uxQueueMessagesWaiting(canQueue), CAN_QUEUE_SIZE,
+            loggingEnabled ? "ON " : "OFF",
+            sdCardReady ? "OK" : "NO",
+            totalMsgCount, totalTxCount,
+            timeSyncStatus.synchronized ? "OK" : "NO",
+            timeSyncStatus.rtcAvailable ? "OK" : "NO");
+        lastPrint = millis();
+    }
 }
\ No newline at end of file