Update flipper and can_sniffer

can_sniffer/src/handlers/flipper_handler.py

@@ -1,8 +1,15 @@
 """
-Flipper Zero UART Handler.
+Flipper Zero UART Handler with Handshake Protocol.
 
-Sends CAN sniffer statistics to Flipper Zero via UART.
+Waits for INIT command from Flipper Zero before sending statistics.
-Provides real-time monitoring on Flipper Zero display.
+Supports handshake protocol for secure connection establishment.
+
+Protocol:
+    1. RPI5 waits in passive mode, listening for commands
+    2. Flipper sends: INIT:flipper\n
+    3. RPI5 responds: ACK:rpi5,ip=x.x.x.x\n
+    4. RPI5 starts sending: STATS:ip=...,total=...,pending=...,processed=...\n
+    5. Flipper sends: STOP:flipper\n to disconnect
 """
 
 import socket
@@ -26,10 +33,8 @@ def get_ip_address() -> str:
         IP address string or "0.0.0.0" if unable to determine
     """
     try:
-        # Create a socket to determine the outgoing IP
         s = socket.socket(socket.AF_INET, socket.SOCK_DGRAM)
         s.settimeout(0.1)
-        # Connect to a public address (doesn't actually send data)
         s.connect(("8.8.8.8", 80))
         ip = s.getsockname()[0]
         s.close()
@@ -37,7 +42,6 @@ def get_ip_address() -> str:
     except Exception:
         pass
 
-    # Fallback: try to get any non-localhost IP
     try:
         hostname = socket.gethostname()
         ip = socket.gethostbyname(hostname)
@@ -51,15 +55,18 @@ def get_ip_address() -> str:
 
 class FlipperHandler(BaseHandler):
     """
-    Handler that sends statistics to Flipper Zero via UART.
+    Handler that communicates with Flipper Zero via UART.
+
+    Implements handshake protocol:
+    - Waits for INIT:flipper command
+    - Responds with ACK:rpi5,ip=x.x.x.x
+    - Sends STATS periodically while connected
+    - Stops on STOP:flipper command
 
     UART Configuration:
         - Device: /dev/ttyAMA0 (or configured device)
         - Baud: 115200
         - Format: 8N1
-
-    Protocol:
-        Sends text line: STATS:ip=<ip>,total=<n>,pending=<n>,processed=<n>\n
     """
 
     def __init__(self, enabled: Optional[bool] = None):
@@ -69,7 +76,6 @@ class FlipperHandler(BaseHandler):
         Args:
             enabled: Whether handler is enabled. If None, reads from config.
         """
-        # Check config for enabled status
         if enabled is None:
             enabled = getattr(config, "flipper", None) is not None
             if enabled:
@@ -80,15 +86,18 @@ class FlipperHandler(BaseHandler):
         self.serial_port: Optional[Any] = None
         self.device = "/dev/ttyAMA0"
         self.baudrate = 115200
-        self.send_interval = 1.0  # Send stats every 1 second
+        self.send_interval = 1.0
 
-        # Load config if available
         if hasattr(config, "flipper"):
             flipper_cfg = config.flipper
             self.device = getattr(flipper_cfg, "device", self.device)
             self.baudrate = getattr(flipper_cfg, "baudrate", self.baudrate)
             self.send_interval = getattr(flipper_cfg, "send_interval", self.send_interval)
 
+        # Connection state
+        self._connected = False
+        self._running = False
+
         # Statistics
         self._stats_lock = threading.Lock()
         self._total_frames = 0
@@ -97,17 +106,16 @@ class FlipperHandler(BaseHandler):
         self._sent_count = 0
         self._error_count = 0
 
-        # Background sender thread
+        # Threads
-        self._sender_thread: Optional[threading.Thread] = None
+        self._rx_thread: Optional[threading.Thread] = None
-        self._running = False
+        self._tx_thread: Optional[threading.Thread] = None
 
-        # IP address cache
+        # IP address
         self._ip_address = "0.0.0.0"
-        self._last_ip_check = 0
 
     def initialize(self) -> bool:
         """
-        Initialize UART connection to Flipper Zero.
+        Initialize UART connection.
 
         Returns:
             True if initialization successful
@@ -124,13 +132,12 @@ class FlipperHandler(BaseHandler):
                 timeout=0.1,
             )
 
-            # Get initial IP address
             self._ip_address = get_ip_address()
-            self._last_ip_check = time.time()
-
             self._initialized = True
+
             self.logger.info(
-                f"Flipper handler initialized on {self.device} @ {self.baudrate} baud"
+                f"Flipper handler initialized on {self.device} @ {self.baudrate} baud, "
+                f"IP: {self._ip_address}"
             )
             return True
 
@@ -142,71 +149,145 @@ class FlipperHandler(BaseHandler):
             return False
 
     def start(self) -> None:
-        """Start the background sender thread."""
+        """Start the RX listener and TX sender threads."""
         if self._running:
             return
 
         self._running = True
-        self._sender_thread = threading.Thread(
+        self._connected = False
-            target=self._sender_loop, name="FlipperSender", daemon=True
+
-        )
+        # Start RX thread (listens for commands)
-        self._sender_thread.start()
+        self._rx_thread = threading.Thread(
-        self.logger.info("Flipper sender thread started")
+            target=self._rx_loop, name="FlipperRX", daemon=True
+        )
+        self._rx_thread.start()
+
+        # Start TX thread (sends stats when connected)
+        self._tx_thread = threading.Thread(
+            target=self._tx_loop, name="FlipperTX", daemon=True
+        )
+        self._tx_thread.start()
+
+        self.logger.info("Flipper handler started, waiting for connection...")
+
+    def _rx_loop(self) -> None:
+        """Receive loop - listens for commands from Flipper."""
+        buffer = ""
 
-    def _sender_loop(self) -> None:
-        """Background loop that sends stats periodically."""
         while self._running:
             try:
-                self._send_stats()
+                if not self.serial_port or not self.serial_port.is_open:
+                    time.sleep(0.1)
+                    continue
+
+                # Read available data
+                if self.serial_port.in_waiting > 0:
+                    data = self.serial_port.read(self.serial_port.in_waiting)
+                    buffer += data.decode("utf-8", errors="ignore")
+
+                    # Process complete lines
+                    while "\n" in buffer:
+                        line, buffer = buffer.split("\n", 1)
+                        line = line.strip()
+                        if line:
+                            self._process_command(line)
+                else:
+                    time.sleep(0.05)
+
             except Exception as e:
-                self.logger.debug(f"Error sending stats to Flipper: {e}")
+                self.logger.debug(f"RX error: {e}")
-                with self._stats_lock:
+                time.sleep(0.1)
-                    self._error_count += 1
+
+    def _process_command(self, command: str) -> None:
+        """
+        Process received command from Flipper.
+
+        Args:
+            command: Received command string
+        """
+        self.logger.info(f"Received command: {command}")
+
+        if command.startswith("INIT:"):
+            # Handshake initiation
+            client_id = command[5:].strip()
+            self.logger.info(f"Handshake request from: {client_id}")
+
+            # Send ACK with IP address
+            self._ip_address = get_ip_address()
+            ack_msg = f"ACK:rpi5,ip={self._ip_address}\n"
+            self._send_raw(ack_msg)
+
+            self._connected = True
+            self.logger.info(f"Connected to Flipper, IP: {self._ip_address}")
+
+        elif command.startswith("STOP:"):
+            # Disconnect request
+            client_id = command[5:].strip()
+            self.logger.info(f"Disconnect request from: {client_id}")
+            self._connected = False
+            self.logger.info("Disconnected from Flipper")
+
+    def _tx_loop(self) -> None:
+        """Transmit loop - sends stats when connected."""
+        while self._running:
+            try:
+                if self._connected:
+                    self._send_stats()
 
                 time.sleep(self.send_interval)
 
+            except Exception as e:
+                self.logger.debug(f"TX error: {e}")
+                with self._stats_lock:
+                    self._error_count += 1
+
+    def _send_raw(self, message: str) -> bool:
+        """
+        Send raw message via UART.
+
+        Args:
+            message: Message to send
+
+        Returns:
+            True if sent successfully
+        """
+        if not self.serial_port or not self.serial_port.is_open:
+            return False
+
+        try:
+            self.serial_port.write(message.encode("utf-8"))
+            self.serial_port.flush()
+            self.logger.debug(f"TX: {message.strip()}")
+            return True
+        except Exception as e:
+            self.logger.debug(f"Send error: {e}")
+            return False
+
     def _send_stats(self) -> None:
         """Send current statistics to Flipper Zero."""
-        if not self.serial_port or not self.serial_port.is_open:
+        if not self._connected:
             return
 
-        # Refresh IP address every 60 seconds
-        current_time = time.time()
-        if current_time - self._last_ip_check > 60:
-            self._ip_address = get_ip_address()
-            self._last_ip_check = current_time
-
         with self._stats_lock:
             total = self._total_frames
             pending = self._pending_frames
             processed = self._processed_frames
 
-        # Build stats message
         message = f"STATS:ip={self._ip_address},total={total},pending={pending},processed={processed}\n"
 
-        try:
+        if self._send_raw(message):
-            self.serial_port.write(message.encode("utf-8"))
-            self.serial_port.flush()
-
             with self._stats_lock:
                 self._sent_count += 1
 
-        except Exception as e:
-            self.logger.debug(f"UART write error: {e}")
-            with self._stats_lock:
-                self._error_count += 1
-
     def handle(self, frame: CANFrame) -> bool:
         """
         Handle a single CAN frame.
 
-        Updates frame counters for statistics.
-
         Args:
             frame: CANFrame to handle
 
         Returns:
-            True (always succeeds, just updates counters)
+            True (always succeeds)
         """
         with self._stats_lock:
             self._total_frames += 1
@@ -221,14 +302,12 @@ class FlipperHandler(BaseHandler):
             frames: List of CANFrame objects
 
         Returns:
-            Number of frames processed (all of them)
+            Number of frames processed
         """
         count = len(frames)
         with self._stats_lock:
             self._total_frames += count
-            # After batch processing, frames are processed
             self._processed_frames += count
-            # Reduce pending by batch count
             self._pending_frames = max(0, self._pending_frames - count)
         return count
 
@@ -236,8 +315,6 @@ class FlipperHandler(BaseHandler):
         """
         Update pending frame count.
 
-        Called externally to sync with actual queue size.
-
         Args:
             pending_count: Current number of pending frames
         """
@@ -245,26 +322,30 @@ class FlipperHandler(BaseHandler):
             self._pending_frames = pending_count
 
     def flush(self) -> None:
-        """Flush - send immediate stats update."""
+        """Flush - send immediate stats if connected."""
+        if self._connected:
             try:
                 self._send_stats()
             except Exception as e:
-            self.logger.debug(f"Error in flush: {e}")
+                self.logger.debug(f"Flush error: {e}")
 
     def shutdown(self) -> None:
         """Shutdown the handler."""
         self.logger.info("Shutting down Flipper handler...")
 
         self._running = False
+        self._connected = False
 
-        if self._sender_thread and self._sender_thread.is_alive():
+        # Wait for threads
-            self._sender_thread.join(timeout=2.0)
+        if self._rx_thread and self._rx_thread.is_alive():
+            self._rx_thread.join(timeout=2.0)
 
+        if self._tx_thread and self._tx_thread.is_alive():
+            self._tx_thread.join(timeout=2.0)
+
+        # Close serial port
         if self.serial_port and self.serial_port.is_open:
             try:
-                # Send final "disconnected" message
-                self.serial_port.write(b"STATS:ip=---,total=0,pending=0,processed=0\n")
-                self.serial_port.flush()
                 self.serial_port.close()
             except Exception as e:
                 self.logger.debug(f"Error closing serial port: {e}")
@@ -288,6 +369,10 @@ class FlipperHandler(BaseHandler):
                 "error_count": self._error_count,
                 "device": self.device,
                 "baudrate": self.baudrate,
-                "connected": self.serial_port.is_open if self.serial_port else False,
+                "connected": self._connected,
                 "ip_address": self._ip_address,
             }
+
+    def is_connected(self) -> bool:
+        """Check if Flipper is connected."""
+        return self._connected

flip_monitor/can_monitor.c

@@ -1,206 +1,325 @@
 /**
  * CAN Monitor for Flipper Zero
  *
- * Receives CAN sniffer statistics from RPI5 via UART.
+ * Multi-page application with handshake protocol.
- * Displays: IP address, total frames, pending frames, processed frames.
  *
- * UART Configuration:
+ * Handshake:
- *   - TX: GPIO 13 (pin 13)
+ *   1. User presses OK on welcome screen
- *   - RX: GPIO 14 (pin 14)
+ *   2. Flipper sends: INIT:flipper\n
- *   - Baud: 115200
+ *   3. RPI5 responds: ACK:rpi5,ip=x.x.x.x\n
- *   - 8N1
+ *   4. Flipper allows navigation to stats page
+ *   5. RPI5 starts sending: STATS:ip=...,total=...,pending=...,processed=...\n
  *
- * Protocol: Text-based
+ * Wiring:
- *   Format: STATS:ip=<ip>,total=<n>,pending=<n>,processed=<n>\n
+ *   RPI5 TX (GPIO14, Pin 8)  -> Flipper RX (Pin 14)
- *   Example: STATS:ip=192.168.1.100,total=12345,pending=100,processed=12245\n
+ *   RPI5 RX (GPIO15, Pin 10) <- Flipper TX (Pin 13)
+ *   RPI5 GND (Pin 6)         -> Flipper GND (Pin 8/11/18)
  */
 
 #include <furi.h>
 #include <furi_hal.h>
 #include <gui/gui.h>
 #include <gui/view_port.h>
-#include <notification/notification.h>
-#include <notification/notification_messages.h>
-
 #include <expansion/expansion.h>
-#include <furi_hal_serial.h>
 
 #include <stdlib.h>
 #include <string.h>
 
 #define TAG "CANMonitor"
-
-// UART configuration
-#define UART_CH FuriHalSerialIdUsart
 #define UART_BAUD 115200
-
-// Buffer sizes
 #define RX_BUFFER_SIZE 256
 #define IP_BUFFER_SIZE 32
 
-// Statistics structure
+// Connection state
+typedef enum {
+    StateDisconnected,
+    StateConnecting,
+    StateConnected,
+} ConnectionState;
+
+// Pages
+typedef enum {
+    PageWelcome,
+    PageStats,
+} AppPage;
+
+// Statistics
 typedef struct {
     char ip_address[IP_BUFFER_SIZE];
     uint32_t total_frames;
     uint32_t pending_frames;
     uint32_t processed_frames;
-    bool connected;
+    bool data_received;
     uint32_t last_update_tick;
 } CanStats;
 
-// Application context
+// App context
 typedef struct {
     Gui* gui;
     ViewPort* view_port;
-    FuriMessageQueue* event_queue;
     FuriMutex* mutex;
 
-    FuriHalSerialHandle* serial_handle;
+    FuriHalSerialHandle* serial;
     FuriStreamBuffer* rx_stream;
-    FuriThread* rx_thread;
+    FuriThread* worker_thread;
 
     CanStats stats;
-    bool running;
+    AppPage current_page;
+    ConnectionState conn_state;
+    volatile bool running;
+    volatile bool send_init;
 } CanMonitorApp;
 
-// Event types
+// Send data via UART
-typedef enum {
+static void uart_send(CanMonitorApp* app, const char* data) {
-    EventTypeKey,
+    if(app->serial) {
-    EventTypeStats,
+        furi_hal_serial_tx(app->serial, (uint8_t*)data, strlen(data));
-} EventType;
+        FURI_LOG_I(TAG, "TX: %s", data);
+    }
+}
 
-typedef struct {
+// Parse ACK response: ACK:rpi5,ip=x.x.x.x
-    EventType type;
+static bool parse_ack(const char* line, CanStats* stats) {
-    InputEvent input;
+    if(strncmp(line, "ACK:", 4) != 0) {
-} CanMonitorEvent;
+        return false;
+    }
 
-// Parse statistics from received line
+    const char* p = line + 4;
-static bool parse_stats_line(const char* line, CanStats* stats) {
+
-    // Format: STATS:ip=192.168.1.100,total=12345,pending=100,processed=12245
+    // Check for rpi5 identifier
+    if(strncmp(p, "rpi5", 4) != 0) {
+        return false;
+    }
+
+    // Parse ip=
+    const char* ip = strstr(p, "ip=");
+    if(ip) {
+        ip += 3;
+        // Find end (comma, newline, or end of string)
+        size_t len = 0;
+        while(ip[len] && ip[len] != ',' && ip[len] != '\n' && ip[len] != '\r') {
+            len++;
+        }
+        if(len > 0 && len < IP_BUFFER_SIZE) {
+            memcpy(stats->ip_address, ip, len);
+            stats->ip_address[len] = '\0';
+        }
+    }
+
+    return true;
+}
+
+// Parse STATS: STATS:ip=x.x.x.x,total=N,pending=N,processed=N
+static bool parse_stats(const char* line, CanStats* stats) {
     if(strncmp(line, "STATS:", 6) != 0) {
         return false;
     }
 
-    const char* data = line + 6;
+    const char* p = line + 6;
 
     // Parse ip=
-    const char* ip_start = strstr(data, "ip=");
+    const char* ip = strstr(p, "ip=");
-    if(ip_start) {
+    if(ip) {
-        ip_start += 3;
+        ip += 3;
-        const char* ip_end = strchr(ip_start, ',');
+        const char* end = strchr(ip, ',');
-        if(ip_end) {
+        if(end && (size_t)(end - ip) < IP_BUFFER_SIZE) {
-            size_t len = ip_end - ip_start;
+            size_t len = end - ip;
-            if(len < IP_BUFFER_SIZE) {
+            memcpy(stats->ip_address, ip, len);
-                strncpy(stats->ip_address, ip_start, len);
             stats->ip_address[len] = '\0';
         }
     }
-    }
 
     // Parse total=
-    const char* total_start = strstr(data, "total=");
+    const char* total = strstr(p, "total=");
-    if(total_start) {
+    if(total) {
-        stats->total_frames = strtoul(total_start + 6, NULL, 10);
+        stats->total_frames = strtoul(total + 6, NULL, 10);
     }
 
     // Parse pending=
-    const char* pending_start = strstr(data, "pending=");
+    const char* pending = strstr(p, "pending=");
-    if(pending_start) {
+    if(pending) {
-        stats->pending_frames = strtoul(pending_start + 8, NULL, 10);
+        stats->pending_frames = strtoul(pending + 8, NULL, 10);
     }
 
     // Parse processed=
-    const char* processed_start = strstr(data, "processed=");
+    const char* processed = strstr(p, "processed=");
-    if(processed_start) {
+    if(processed) {
-        stats->processed_frames = strtoul(processed_start + 10, NULL, 10);
+        stats->processed_frames = strtoul(processed + 10, NULL, 10);
     }
 
-    stats->connected = true;
+    stats->data_received = true;
     stats->last_update_tick = furi_get_tick();
 
     return true;
 }
 
-// UART receive callback
+// Process received line
-static void uart_rx_callback(
+static void process_line(CanMonitorApp* app, const char* line) {
-    FuriHalSerialHandle* handle,
+    FURI_LOG_I(TAG, "RX: %s", line);
-    FuriHalSerialRxEvent event,
+
-    void* context) {
+    furi_mutex_acquire(app->mutex, FuriWaitForever);
-    CanMonitorApp* app = context;
+
-    UNUSED(handle);
+    if(app->conn_state == StateConnecting) {
+        // Waiting for ACK
+        if(parse_ack(line, &app->stats)) {
+            FURI_LOG_I(TAG, "ACK received, IP: %s", app->stats.ip_address);
+            app->conn_state = StateConnected;
+        }
+    } else if(app->conn_state == StateConnected) {
+        // Parse stats
+        parse_stats(line, &app->stats);
+    }
+
+    furi_mutex_release(app->mutex);
+    view_port_update(app->view_port);
+}
+
+// UART RX callback
+static void uart_callback(FuriHalSerialHandle* handle, FuriHalSerialRxEvent event, void* ctx) {
+    CanMonitorApp* app = ctx;
 
     if(event == FuriHalSerialRxEventData) {
-        uint8_t data = furi_hal_serial_async_rx(handle);
+        uint8_t byte = furi_hal_serial_async_rx(handle);
-        furi_stream_buffer_send(app->rx_stream, &data, 1, 0);
+        furi_stream_buffer_send(app->rx_stream, &byte, 1, 0);
     }
 }
 
-// UART receive thread
+// Worker thread
-static int32_t uart_rx_thread(void* context) {
+static int32_t worker_thread(void* ctx) {
-    CanMonitorApp* app = context;
+    CanMonitorApp* app = ctx;
-    char rx_buffer[RX_BUFFER_SIZE];
+    char buffer[RX_BUFFER_SIZE];
-    size_t rx_index = 0;
+    size_t idx = 0;
+    uint32_t last_rx_tick = 0;
+
+    FURI_LOG_I(TAG, "Worker started");
 
     while(app->running) {
-        uint8_t data;
+        // Check if we need to send INIT
-        size_t len = furi_stream_buffer_receive(app->rx_stream, &data, 1, 100);
+        if(app->send_init) {
+            app->send_init = false;
+            uart_send(app, "INIT:flipper\n");
+
+            furi_mutex_acquire(app->mutex, FuriWaitForever);
+            app->conn_state = StateConnecting;
+            furi_mutex_release(app->mutex);
+            view_port_update(app->view_port);
+        }
+
+        // Receive data
+        uint8_t byte;
+        size_t len = furi_stream_buffer_receive(app->rx_stream, &byte, 1, 50);
 
         if(len > 0) {
-            if(data == '\n' || data == '\r') {
+            last_rx_tick = furi_get_tick();
-                if(rx_index > 0) {
-                    rx_buffer[rx_index] = '\0';
 
-                    // Parse the received line
+            if(byte == '\n' || byte == '\r') {
+                if(idx > 0) {
+                    buffer[idx] = '\0';
+                    process_line(app, buffer);
+                    idx = 0;
+                }
+            } else if(idx < RX_BUFFER_SIZE - 1) {
+                buffer[idx++] = byte;
+            }
+        } else {
+            // Timeout: parse partial data after 500ms
+            if(idx > 0 && (furi_get_tick() - last_rx_tick) > 500) {
+                buffer[idx] = '\0';
+                process_line(app, buffer);
+                idx = 0;
+            }
+        }
+
+        // Check data timeout (5 sec) - only when connected
         furi_mutex_acquire(app->mutex, FuriWaitForever);
-                    if(parse_stats_line(rx_buffer, &app->stats)) {
+        if(app->conn_state == StateConnected && app->stats.data_received) {
-                        // Notify view to redraw
+            if((furi_get_tick() - app->stats.last_update_tick) > 5000) {
+                app->stats.data_received = false;
                 view_port_update(app->view_port);
             }
-                    furi_mutex_release(app->mutex);
-
-                    rx_index = 0;
-                }
-            } else if(rx_index < RX_BUFFER_SIZE - 1) {
-                rx_buffer[rx_index++] = data;
-            }
-        }
-
-        // Check connection timeout (5 seconds)
-        furi_mutex_acquire(app->mutex, FuriWaitForever);
-        if(app->stats.connected &&
-           (furi_get_tick() - app->stats.last_update_tick) > 5000) {
-            app->stats.connected = false;
-            view_port_update(app->view_port);
         }
         furi_mutex_release(app->mutex);
     }
 
+    FURI_LOG_I(TAG, "Worker stopped");
     return 0;
 }
 
-// Draw callback
+// Draw welcome page
-static void draw_callback(Canvas* canvas, void* context) {
+static void draw_welcome(Canvas* canvas, CanMonitorApp* app) {
-    CanMonitorApp* app = context;
-
-    furi_mutex_acquire(app->mutex, FuriWaitForever);
-
     canvas_clear(canvas);
-    canvas_set_font(canvas, FontPrimary);
 
     // Title
-    canvas_draw_str_aligned(canvas, 64, 2, AlignCenter, AlignTop, "CAN Monitor");
+    canvas_set_font(canvas, FontPrimary);
+    canvas_draw_str_aligned(canvas, 64, 8, AlignCenter, AlignCenter, "CAN Monitor");
 
     canvas_set_font(canvas, FontSecondary);
 
-    // Connection status
+    // Subtitle
-    if(app->stats.connected) {
+    canvas_draw_str_aligned(canvas, 64, 22, AlignCenter, AlignCenter, "RPI5 CAN Sniffer");
-        canvas_draw_str(canvas, 0, 14, "Status: Connected");
+
-    } else {
+    // Status based on connection state
-        canvas_draw_str(canvas, 0, 14, "Status: Waiting...");
+    furi_mutex_acquire(app->mutex, FuriWaitForever);
+    ConnectionState state = app->conn_state;
+    char ip_buf[IP_BUFFER_SIZE];
+    strncpy(ip_buf, app->stats.ip_address, IP_BUFFER_SIZE);
+    furi_mutex_release(app->mutex);
+
+    switch(state) {
+        case StateDisconnected:
+            canvas_draw_str_aligned(canvas, 64, 38, AlignCenter, AlignCenter, "Press OK to connect");
+            canvas_draw_str_aligned(canvas, 64, 50, AlignCenter, AlignCenter, "[OK]");
+            break;
+
+        case StateConnecting:
+            canvas_draw_str_aligned(canvas, 64, 38, AlignCenter, AlignCenter, "Connecting...");
+            canvas_draw_str_aligned(canvas, 64, 50, AlignCenter, AlignCenter, "Waiting for RPI5");
+            break;
+
+        case StateConnected:
+            canvas_draw_str_aligned(canvas, 64, 34, AlignCenter, AlignCenter, "Connected!");
+            if(strlen(ip_buf) > 0) {
+                char buf[48];
+                snprintf(buf, sizeof(buf), "RPI5: %s", ip_buf);
+                canvas_draw_str_aligned(canvas, 64, 46, AlignCenter, AlignCenter, buf);
+            }
+            canvas_draw_str_aligned(canvas, 64, 58, AlignCenter, AlignCenter, "Press RIGHT >");
+            break;
+    }
 }
 
-    // IP Address
+// Draw stats page
+static void draw_stats(Canvas* canvas, CanMonitorApp* app) {
     char buf[64];
+
+    canvas_clear(canvas);
+
+    // Header
+    canvas_set_font(canvas, FontPrimary);
+    canvas_draw_str(canvas, 10, 10, "CAN Monitor");
+
+    // Navigation hint
+    canvas_draw_str(canvas, 0, 10, "<");
+
+    // Connection indicator
+    furi_mutex_acquire(app->mutex, FuriWaitForever);
+    bool data_ok = app->stats.data_received;
+    furi_mutex_release(app->mutex);
+
+    if(data_ok) {
+        canvas_draw_disc(canvas, 120, 6, 4);
+    } else {
+        canvas_draw_circle(canvas, 120, 6, 4);
+    }
+
+    // Separator
+    canvas_draw_line(canvas, 0, 14, 128, 14);
+
+    canvas_set_font(canvas, FontSecondary);
+
+    furi_mutex_acquire(app->mutex, FuriWaitForever);
+
+    // IP Address
     if(strlen(app->stats.ip_address) > 0) {
         snprintf(buf, sizeof(buf), "IP: %s", app->stats.ip_address);
     } else {
@@ -209,7 +328,7 @@ static void draw_callback(Canvas* canvas, void* context) {
     canvas_draw_str(canvas, 0, 26, buf);
 
     // Total frames
-    snprintf(buf, sizeof(buf), "Total: %lu", (unsigned long)app->stats.total_frames);
+    snprintf(buf, sizeof(buf), "Total frames: %lu", (unsigned long)app->stats.total_frames);
     canvas_draw_str(canvas, 0, 38, buf);
 
     // Pending frames
@@ -218,110 +337,158 @@ static void draw_callback(Canvas* canvas, void* context) {
 
     // Processed frames
     snprintf(buf, sizeof(buf), "Processed: %lu", (unsigned long)app->stats.processed_frames);
-    canvas_draw_str(canvas, 0, 62, buf);
+    canvas_draw_str(canvas, 4, 62, buf);
 
     furi_mutex_release(app->mutex);
 }
 
-// Input callback
+// Draw callback
-static void input_callback(InputEvent* input_event, void* context) {
+static void draw_callback(Canvas* canvas, void* ctx) {
-    CanMonitorApp* app = context;
+    CanMonitorApp* app = ctx;
-    CanMonitorEvent event = {.type = EventTypeKey, .input = *input_event};
+
-    furi_message_queue_put(app->event_queue, &event, FuriWaitForever);
+    switch(app->current_page) {
+        case PageWelcome:
+            draw_welcome(canvas, app);
+            break;
+        case PageStats:
+            draw_stats(canvas, app);
+            break;
+    }
 }
 
-// Initialize application
+// Input callback
-static CanMonitorApp* can_monitor_app_alloc(void) {
+static void input_callback(InputEvent* event, void* ctx) {
+    CanMonitorApp* app = ctx;
+
+    if(event->type == InputTypeShort) {
+        furi_mutex_acquire(app->mutex, FuriWaitForever);
+
+        switch(event->key) {
+            case InputKeyOk:
+                if(app->current_page == PageWelcome && app->conn_state == StateDisconnected) {
+                    // Start handshake
+                    app->send_init = true;
+                }
+                break;
+
+            case InputKeyRight:
+                // Only allow if connected
+                if(app->current_page == PageWelcome && app->conn_state == StateConnected) {
+                    app->current_page = PageStats;
+                    view_port_update(app->view_port);
+                }
+                break;
+
+            case InputKeyLeft:
+                if(app->current_page == PageStats) {
+                    app->current_page = PageWelcome;
+                    view_port_update(app->view_port);
+                }
+                break;
+
+            case InputKeyBack:
+                if(app->current_page == PageWelcome) {
+                    app->running = false;
+                } else {
+                    app->current_page = PageWelcome;
+                    view_port_update(app->view_port);
+                }
+                break;
+
+            default:
+                break;
+        }
+
+        furi_mutex_release(app->mutex);
+    }
+}
+
+// Main entry point
+int32_t can_monitor_app(void* p) {
+    UNUSED(p);
+
+    FURI_LOG_I(TAG, "Starting CAN Monitor");
+
+    // Allocate app
     CanMonitorApp* app = malloc(sizeof(CanMonitorApp));
     memset(app, 0, sizeof(CanMonitorApp));
-
     app->running = true;
+    app->current_page = PageWelcome;
+    app->conn_state = StateDisconnected;
+    app->send_init = false;
+
+    // Mutex
     app->mutex = furi_mutex_alloc(FuriMutexTypeNormal);
-    app->event_queue = furi_message_queue_alloc(8, sizeof(CanMonitorEvent));
 
-    // Initialize stats
+    // Disable expansion protocol
-    memset(&app->stats, 0, sizeof(CanStats));
-    strcpy(app->stats.ip_address, "");
-
-    // Disable expansion protocol to use UART
     Expansion* expansion = furi_record_open(RECORD_EXPANSION);
     expansion_disable(expansion);
     furi_record_close(RECORD_EXPANSION);
 
-    // Initialize UART
+    FURI_LOG_I(TAG, "Expansion disabled");
+
+    // Init UART
     app->rx_stream = furi_stream_buffer_alloc(RX_BUFFER_SIZE, 1);
-    app->serial_handle = furi_hal_serial_control_acquire(UART_CH);
+    app->serial = furi_hal_serial_control_acquire(FuriHalSerialIdUsart);
-    furi_hal_serial_init(app->serial_handle, UART_BAUD);
-    furi_hal_serial_async_rx_start(app->serial_handle, uart_rx_callback, app, false);
 
-    // Start RX thread
+    if(app->serial) {
-    app->rx_thread = furi_thread_alloc_ex("CANMonitorRx", 1024, uart_rx_thread, app);
+        furi_hal_serial_init(app->serial, UART_BAUD);
-    furi_thread_start(app->rx_thread);
+        furi_hal_serial_async_rx_start(app->serial, uart_callback, app, false);
+        FURI_LOG_I(TAG, "UART initialized at %d baud", UART_BAUD);
+    } else {
+        FURI_LOG_E(TAG, "Failed to acquire UART");
+    }
 
-    // Initialize GUI
+    // Start worker
+    app->worker_thread = furi_thread_alloc_ex("CanMonitorWorker", 1024, worker_thread, app);
+    furi_thread_start(app->worker_thread);
+
+    // Init GUI
     app->gui = furi_record_open(RECORD_GUI);
     app->view_port = view_port_alloc();
     view_port_draw_callback_set(app->view_port, draw_callback, app);
     view_port_input_callback_set(app->view_port, input_callback, app);
     gui_add_view_port(app->gui, app->view_port, GuiLayerFullscreen);
 
-    return app;
+    FURI_LOG_I(TAG, "GUI initialized, waiting for user input");
+
+    // Main loop
+    while(app->running) {
+        furi_delay_ms(100);
     }
 
-// Free application
+    FURI_LOG_I(TAG, "Shutting down");
-static void can_monitor_app_free(CanMonitorApp* app) {
-    // Stop RX thread
-    app->running = false;
-    furi_thread_join(app->rx_thread);
-    furi_thread_free(app->rx_thread);
 
-    // Deinitialize UART
+    // Send disconnect signal
-    furi_hal_serial_async_rx_stop(app->serial_handle);
+    if(app->conn_state == StateConnected) {
-    furi_hal_serial_deinit(app->serial_handle);
+        uart_send(app, "STOP:flipper\n");
-    furi_hal_serial_control_release(app->serial_handle);
+    }
+
+    // Cleanup
+    furi_thread_join(app->worker_thread);
+    furi_thread_free(app->worker_thread);
+
+    if(app->serial) {
+        furi_hal_serial_async_rx_stop(app->serial);
+        furi_hal_serial_deinit(app->serial);
+        furi_hal_serial_control_release(app->serial);
+    }
     furi_stream_buffer_free(app->rx_stream);
 
-    // Re-enable expansion protocol
+    // Re-enable expansion
-    Expansion* expansion = furi_record_open(RECORD_EXPANSION);
+    expansion = furi_record_open(RECORD_EXPANSION);
     expansion_enable(expansion);
     furi_record_close(RECORD_EXPANSION);
 
-    // Free GUI
     view_port_enabled_set(app->view_port, false);
     gui_remove_view_port(app->gui, app->view_port);
     view_port_free(app->view_port);
     furi_record_close(RECORD_GUI);
 
-    furi_message_queue_free(app->event_queue);
     furi_mutex_free(app->mutex);
-
     free(app);
-}
 
-// Main application entry point
+    FURI_LOG_I(TAG, "Bye!");
-int32_t can_monitor_app(void* p) {
-    UNUSED(p);
-
-    CanMonitorApp* app = can_monitor_app_alloc();
-
-    CanMonitorEvent event;
-    bool running = true;
-
-    // Main event loop
-    while(running) {
-        if(furi_message_queue_get(app->event_queue, &event, 100) == FuriStatusOk) {
-            if(event.type == EventTypeKey) {
-                if(event.input.type == InputTypeShort ||
-                   event.input.type == InputTypeLong) {
-                    if(event.input.key == InputKeyBack) {
-                        running = false;
-                    }
-                }
-            }
-        }
-    }
-
-    can_monitor_app_free(app);
 
     return 0;
 }