Fix possible lock-up while reading UART

components/LD2450/LD2450.cpp

@@ -115,8 +115,8 @@ namespace esphome::ld2450
                     else
                     {
                         command_queue_.erase(command_queue_.begin());
-                        command_send_retries_ = 0;
                     }
+                    command_send_retries_ = 0;
                     ESP_LOGW(TAG, "Sending command timed out! Is the sensor connected?");
                 }
                 else
@@ -132,36 +132,41 @@ namespace esphome::ld2450
         {
             // Inject leave config command after clearing the queue
             command_queue_.push_back({COMMAND_LEAVE_CONFIG, 0x00});
+            command_send_retries_ = 0;
         }
 
         // Skip stream until start of message and parse header
-        while (!peek_status_ && available() >= 4)
+        if (!peek_status_ && available() >= 4)
         {
             // Try to read the header and abort on mismatch
             const uint8_t *header;
             bool skip = false;
-            uint8_t target;
-            if (peek() == update_header[0])
+            uint8_t message_type;
+            uint8_t first_byte = read();
+            if (first_byte == update_header[0])
             {
                 header = update_header;
-                target = 1;
+                message_type = 1;
             }
-            else
+            else if (first_byte == config_header[0])
             {
                 header = config_header;
-                target = 2;
+                message_type = 2;
+            }
+            else
+            {
+                skip = true;
             }
 
-            for (int i = 0; i < 4 && !skip; i++)
+            for (int i = 1; i < 4 && !skip; i++)
             {
                 if (read() != header[i])
                     skip = true;
             }
-            if (skip)
-                continue;
 
-            // Flag successful header reading
-            peek_status_ = target;
+            if (!skip)
+                // Flag successful header reading
+                peek_status_ = message_type;
         }
 
         if (peek_status_ == 1 && available() >= 28)
@@ -201,10 +206,25 @@ namespace esphome::ld2450
                 peek_status_ = 0;
             }
         }
+
+        if (sensor_available_ && millis() - last_message_received_ > SENSOR_UNAVAILABLE_TIMEOUT)
+        {
+            sensor_available_ = false;
+
+            ESP_LOGE(TAG, "LD2450-Sensor stopped sending updates!");
+
+            // Update zones and related components
+            for (Zone *zone : zones_)
+            {
+                zone->update(targets_, sensor_available_);
+            }
+        }
     }
 
     void LD2450::process_message(uint8_t *msg, int len)
     {
+        sensor_available_ = true;
+        last_message_received_ = millis();
         for (int i = 0; i < 3; i++)
         {
             int offset = 8 * i;
@@ -251,7 +271,7 @@ namespace esphome::ld2450
         // Update zones and related components
         for (Zone *zone : zones_)
         {
-            zone->update(targets_);
+            zone->update(targets_, sensor_available_);
         }
     }
 
@@ -396,7 +416,7 @@ namespace esphome::ld2450
 
         // Write message length
         write(static_cast<uint8_t>(len));
-        write(static_cast<uint8_t>(len << 8));
+        write(static_cast<uint8_t>(len >> 8));
 
         // Write message content
         write_array(msg, len);

components/LD2450/LD2450.h

@@ -21,7 +21,9 @@
 #include "esphome/components/button/button.h"
 #endif
 
-#define COMMAND_MAX_RETRIES 5
+#define SENSOR_UNAVAILABLE_TIMEOUT 1000
+
+#define COMMAND_MAX_RETRIES 10
 #define COMMAND_RETRY_DELAY 100
 
 #define COMMAND_ENTER_CONFIG 0xFF
@@ -215,6 +217,15 @@ namespace esphome::ld2450
             return targets_[i];
         }
 
+        /**
+         * @brief Gets the state of the connected sensor
+         * @return True if the sensor is connected and communicating, False otherwise
+         */
+        bool is_sensor_available()
+        {
+            return sensor_available_;
+        }
+
         /**
          * @brief Reads and logs the sensors version number.
          */
@@ -315,11 +326,17 @@ namespace esphome::ld2450
         /// @brief Indicated that the sensor is currently factory resetting
         bool is_applying_changes_ = false;
 
+        /// @brief indicates if the sensor is communicating
+        bool sensor_available_ = false;
+
         /// @brief Expected length of the configuration message
         int configuration_message_length_ = 0;
 
         /// @brief timestamp of the last message which was sent to the sensor
-        long command_last_sent_ = 0;
+        uint32_t command_last_sent_ = 0;
+
+        /// @brief timestamp of the last received message
+        uint32_t last_message_received_ = 0;
 
         /// @brief Queue of commands to execute
         std::vector<std::vector<uint8_t>> command_queue_;

components/LD2450/target.h

@@ -125,7 +125,7 @@ namespace esphome::ld2450
          * @brief Time since last last change in values.
          * @return timestamp in milliseconds since start
          */
-        long get_last_change()
+        uint32_t get_last_change()
         {
             return last_change_;
         }
@@ -206,10 +206,10 @@ namespace esphome::ld2450
         bool fast_off_detection_ = false;
 
         /// @brief time stamp of the last debug message which was sent.
-        long last_debug_message_ = 0;
+        uint32_t last_debug_message_ = 0;
 
         /// @brief time of the last value change
-        long last_change_ = 0;
+        uint32_t last_change_ = 0;
 
         /// @brief sensor reference of the x position sensor
         PollingSensor *x_position_sensor_ = nullptr;

components/LD2450/zone.cpp

@@ -39,8 +39,21 @@ namespace esphome::ld2450
 #endif
     }
 
-    void Zone::update(std::vector<Target *> &targets)
+    void Zone::update(std::vector<Target *> &targets, bool sensor_available)
     {
+        if (!sensor_available)
+        {
+#ifdef USE_BINARY_SENSOR
+            if (occupancy_binary_sensor_ != nullptr)
+                occupancy_binary_sensor_->publish_state(false);
+#endif
+#ifdef USE_SENSOR
+            if (target_count_sensor_ != nullptr)
+                target_count_sensor_->publish_state(NAN);
+#endif
+            return;
+        }
+
         if (polygon_.size() < 3)
             return;
 

components/LD2450/zone.h

@@ -74,8 +74,9 @@ namespace esphome::ld2450
         /**
          * @brief Updates sensors related to this zone.
          * @param targets Reference to a vector of targets which will be used for calculation
+         * @param available True if the sensor is currently available, false otherwise
          * */
-        void update(std::vector<Target *> &targets);
+        void update(std::vector<Target *> &targets, bool sensor_available);
 
         /**
          * Logs the Zone configuration.
@@ -142,6 +143,6 @@ namespace esphome::ld2450
         int target_timeout_ = 5000;
 
         /// @brief Map of targets which are currently tracked inside of this polygon with their last seen timestamp
-        std::map<Target *, long> tracked_targets_{};
+        std::map<Target *, uint32_t> tracked_targets_{};
     };
 } // namespace esphome::ld2450