[esp32] Centralize FreeRTOS task priorities and reduce MAX_PRIORITIES to 16

Co-authored-by: Thomas Rupprecht <rupprecht.thomas@gmail.com>
Co-authored-by: pre-commit-ci-lite[bot] <117423508+pre-commit-ci-lite[bot]@users.noreply.github.com>
Co-authored-by: Jonathan Swoboda <154711427+swoboda1337@users.noreply.github.com>
Co-authored-by: Claude Opus 4.5 <noreply@anthropic.com>

CODEOWNERS

@@ -134,6 +134,7 @@ esphome/components/dfplayer/* @glmnet
 esphome/components/dfrobot_sen0395/* @niklasweber
 esphome/components/dht/* @OttoWinter
 esphome/components/display_menu_base/* @numo68
+esphome/components/dlms_meter/* @SimonFischer04
 esphome/components/dps310/* @kbx81
 esphome/components/ds1307/* @badbadc0ffee
 esphome/components/ds2484/* @mrk-its

esphome/components/dlms_meter/__init__.py

@@ -0,0 +1,57 @@
+import esphome.codegen as cg
+from esphome.components import uart
+import esphome.config_validation as cv
+from esphome.const import CONF_ID, PLATFORM_ESP32, PLATFORM_ESP8266
+
+CODEOWNERS = ["@SimonFischer04"]
+DEPENDENCIES = ["uart"]
+
+CONF_DLMS_METER_ID = "dlms_meter_id"
+CONF_DECRYPTION_KEY = "decryption_key"
+CONF_PROVIDER = "provider"
+
+PROVIDERS = {"generic": 0, "netznoe": 1}
+
+dlms_meter_component_ns = cg.esphome_ns.namespace("dlms_meter")
+DlmsMeterComponent = dlms_meter_component_ns.class_(
+    "DlmsMeterComponent", cg.Component, uart.UARTDevice
+)
+
+
+def validate_key(value):
+    value = cv.string_strict(value)
+    if len(value) != 32:
+        raise cv.Invalid("Decryption key must be 32 hex characters (16 bytes)")
+    try:
+        return [int(value[i : i + 2], 16) for i in range(0, 32, 2)]
+    except ValueError as exc:
+        raise cv.Invalid("Decryption key must be hex values from 00 to FF") from exc
+
+
+CONFIG_SCHEMA = cv.All(
+    cv.Schema(
+        {
+            cv.GenerateID(): cv.declare_id(DlmsMeterComponent),
+            cv.Required(CONF_DECRYPTION_KEY): validate_key,
+            cv.Optional(CONF_PROVIDER, default="generic"): cv.enum(
+                PROVIDERS, lower=True
+            ),
+        }
+    )
+    .extend(uart.UART_DEVICE_SCHEMA)
+    .extend(cv.COMPONENT_SCHEMA),
+    cv.only_on([PLATFORM_ESP8266, PLATFORM_ESP32]),
+)
+
+FINAL_VALIDATE_SCHEMA = uart.final_validate_device_schema(
+    "dlms_meter", baud_rate=2400, require_rx=True
+)
+
+
+async def to_code(config):
+    var = cg.new_Pvariable(config[CONF_ID])
+    await cg.register_component(var, config)
+    await uart.register_uart_device(var, config)
+    key = ", ".join(str(b) for b in config[CONF_DECRYPTION_KEY])
+    cg.add(var.set_decryption_key(cg.RawExpression(f"{{{key}}}")))
+    cg.add(var.set_provider(PROVIDERS[config[CONF_PROVIDER]]))

esphome/components/dlms_meter/dlms.h

@@ -0,0 +1,71 @@
+#pragma once
+
+#include <cstdint>
+
+namespace esphome::dlms_meter {
+
+/*
++-------------------------------+
+|       Ciphering Service       |
++-------------------------------+
+|      System Title Length      |
++-------------------------------+
+|                               |
+|                               |
+|                               |
+|            System             |
+|            Title              |
+|                               |
+|                               |
+|                               |
++-------------------------------+
+|            Length             | (1 or 3 Bytes)
++-------------------------------+
+|     Security Control Byte     |
++-------------------------------+
+|                               |
+|             Frame             |
+|            Counter            |
+|                               |
++-------------------------------+
+|                               |
+~                               ~
+        Encrypted Payload
+~                               ~
+|                               |
++-------------------------------+
+
+Ciphering Service: 0xDB (General-Glo-Ciphering)
+System Title Length: 0x08
+System Title: Unique ID of meter
+Length: 1 Byte=Length <= 127, 3 Bytes=Length > 127 (0x82 & 2 Bytes length)
+Security Control Byte:
+- Bit 3…0: Security_Suite_Id
+- Bit 4: "A" subfield: indicates that authentication is applied
+- Bit 5: "E" subfield: indicates that encryption is applied
+- Bit 6: Key_Set subfield: 0 = Unicast, 1 = Broadcast
+- Bit 7: Indicates the use of compression.
+ */
+
+static constexpr uint8_t DLMS_HEADER_LENGTH = 16;
+static constexpr uint8_t DLMS_HEADER_EXT_OFFSET = 2;  // Extra offset for extended length header
+static constexpr uint8_t DLMS_CIPHER_OFFSET = 0;
+static constexpr uint8_t DLMS_SYST_OFFSET = 1;
+static constexpr uint8_t DLMS_LENGTH_OFFSET = 10;
+static constexpr uint8_t TWO_BYTE_LENGTH = 0x82;
+static constexpr uint8_t DLMS_LENGTH_CORRECTION = 5;  // Header bytes included in length field
+static constexpr uint8_t DLMS_SECBYTE_OFFSET = 11;
+static constexpr uint8_t DLMS_FRAMECOUNTER_OFFSET = 12;
+static constexpr uint8_t DLMS_FRAMECOUNTER_LENGTH = 4;
+static constexpr uint8_t DLMS_PAYLOAD_OFFSET = 16;
+static constexpr uint8_t GLO_CIPHERING = 0xDB;
+static constexpr uint8_t DATA_NOTIFICATION = 0x0F;
+static constexpr uint8_t TIMESTAMP_DATETIME = 0x0C;
+static constexpr uint16_t MAX_MESSAGE_LENGTH = 512;  // Maximum size of message (when having 2 bytes length in header).
+
+// Provider specific quirks
+static constexpr uint8_t NETZ_NOE_MAGIC_BYTE = 0x81;  // Magic length byte used by Netz NOE
+static constexpr uint8_t NETZ_NOE_EXPECTED_MESSAGE_LENGTH = 0xF8;
+static constexpr uint8_t NETZ_NOE_EXPECTED_SECURITY_CONTROL_BYTE = 0x20;
+
+}  // namespace esphome::dlms_meter

esphome/components/dlms_meter/dlms_meter.cpp

@@ -0,0 +1,468 @@
+#include "dlms_meter.h"
+
+#include <cmath>
+
+#if defined(USE_ESP8266_FRAMEWORK_ARDUINO)
+#include <bearssl/bearssl.h>
+#elif defined(USE_ESP32)
+#include "mbedtls/esp_config.h"
+#include "mbedtls/gcm.h"
+#endif
+
+namespace esphome::dlms_meter {
+
+static constexpr const char *TAG = "dlms_meter";
+
+void DlmsMeterComponent::dump_config() {
+  const char *provider_name = this->provider_ == PROVIDER_NETZNOE ? "Netz NOE" : "Generic";
+  ESP_LOGCONFIG(TAG,
+                "DLMS Meter:\n"
+                "  Provider: %s\n"
+                "  Read Timeout: %u ms",
+                provider_name, this->read_timeout_);
+#define DLMS_METER_LOG_SENSOR(s) LOG_SENSOR("  ", #s, this->s##_sensor_);
+  DLMS_METER_SENSOR_LIST(DLMS_METER_LOG_SENSOR, )
+#define DLMS_METER_LOG_TEXT_SENSOR(s) LOG_TEXT_SENSOR("  ", #s, this->s##_text_sensor_);
+  DLMS_METER_TEXT_SENSOR_LIST(DLMS_METER_LOG_TEXT_SENSOR, )
+}
+
+void DlmsMeterComponent::loop() {
+  // Read while data is available, netznoe uses two frames so allow 2x max frame length
+  while (this->available()) {
+    if (this->receive_buffer_.size() >= MBUS_MAX_FRAME_LENGTH * 2) {
+      ESP_LOGW(TAG, "Receive buffer full, dropping remaining bytes");
+      break;
+    }
+    uint8_t c;
+    this->read_byte(&c);
+    this->receive_buffer_.push_back(c);
+    this->last_read_ = millis();
+  }
+
+  if (!this->receive_buffer_.empty() && millis() - this->last_read_ > this->read_timeout_) {
+    this->mbus_payload_.clear();
+    if (!this->parse_mbus_(this->mbus_payload_))
+      return;
+
+    uint16_t message_length;
+    uint8_t systitle_length;
+    uint16_t header_offset;
+    if (!this->parse_dlms_(this->mbus_payload_, message_length, systitle_length, header_offset))
+      return;
+
+    if (message_length < DECODER_START_OFFSET || message_length > MAX_MESSAGE_LENGTH) {
+      ESP_LOGE(TAG, "DLMS: Message length invalid: %u", message_length);
+      this->receive_buffer_.clear();
+      return;
+    }
+
+    // Decrypt in place and then decode the OBIS codes
+    if (!this->decrypt_(this->mbus_payload_, message_length, systitle_length, header_offset))
+      return;
+    this->decode_obis_(&this->mbus_payload_[header_offset + DLMS_PAYLOAD_OFFSET], message_length);
+  }
+}
+
+bool DlmsMeterComponent::parse_mbus_(std::vector<uint8_t> &mbus_payload) {
+  ESP_LOGV(TAG, "Parsing M-Bus frames");
+  uint16_t frame_offset = 0;  // Offset is used if the M-Bus message is split into multiple frames
+
+  while (frame_offset < this->receive_buffer_.size()) {
+    // Ensure enough bytes remain for the minimal intro header before accessing indices
+    if (this->receive_buffer_.size() - frame_offset < MBUS_HEADER_INTRO_LENGTH) {
+      ESP_LOGE(TAG, "MBUS: Not enough data for frame header (need %d, have %d)", MBUS_HEADER_INTRO_LENGTH,
+               (this->receive_buffer_.size() - frame_offset));
+      this->receive_buffer_.clear();
+      return false;
+    }
+
+    // Check start bytes
+    if (this->receive_buffer_[frame_offset + MBUS_START1_OFFSET] != START_BYTE_LONG_FRAME ||
+        this->receive_buffer_[frame_offset + MBUS_START2_OFFSET] != START_BYTE_LONG_FRAME) {
+      ESP_LOGE(TAG, "MBUS: Start bytes do not match");
+      this->receive_buffer_.clear();
+      return false;
+    }
+
+    // Both length bytes must be identical
+    if (this->receive_buffer_[frame_offset + MBUS_LENGTH1_OFFSET] !=
+        this->receive_buffer_[frame_offset + MBUS_LENGTH2_OFFSET]) {
+      ESP_LOGE(TAG, "MBUS: Length bytes do not match");
+      this->receive_buffer_.clear();
+      return false;
+    }
+
+    uint8_t frame_length = this->receive_buffer_[frame_offset + MBUS_LENGTH1_OFFSET];  // Get length of this frame
+
+    // Check if received data is enough for the given frame length
+    if (this->receive_buffer_.size() - frame_offset <
+        frame_length + 3) {  // length field inside packet does not account for second start- + checksum- + stop- byte
+      ESP_LOGE(TAG, "MBUS: Frame too big for received data");
+      this->receive_buffer_.clear();
+      return false;
+    }
+
+    // Ensure we have full frame (header + payload + checksum + stop byte) before accessing stop byte
+    size_t required_total =
+        frame_length + MBUS_HEADER_INTRO_LENGTH + MBUS_FOOTER_LENGTH;  // payload + header + 2 footer bytes
+    if (this->receive_buffer_.size() - frame_offset < required_total) {
+      ESP_LOGE(TAG, "MBUS: Incomplete frame (need %d, have %d)", (unsigned int) required_total,
+               this->receive_buffer_.size() - frame_offset);
+      this->receive_buffer_.clear();
+      return false;
+    }
+
+    if (this->receive_buffer_[frame_offset + frame_length + MBUS_HEADER_INTRO_LENGTH + MBUS_FOOTER_LENGTH - 1] !=
+        STOP_BYTE) {
+      ESP_LOGE(TAG, "MBUS: Invalid stop byte");
+      this->receive_buffer_.clear();
+      return false;
+    }
+
+    // Verify checksum: sum of all bytes starting at MBUS_HEADER_INTRO_LENGTH, take last byte
+    uint8_t checksum = 0;  // use uint8_t so only the 8 least significant bits are stored
+    for (uint16_t i = 0; i < frame_length; i++) {
+      checksum += this->receive_buffer_[frame_offset + MBUS_HEADER_INTRO_LENGTH + i];
+    }
+    if (checksum != this->receive_buffer_[frame_offset + frame_length + MBUS_HEADER_INTRO_LENGTH]) {
+      ESP_LOGE(TAG, "MBUS: Invalid checksum: %x != %x", checksum,
+               this->receive_buffer_[frame_offset + frame_length + MBUS_HEADER_INTRO_LENGTH]);
+      this->receive_buffer_.clear();
+      return false;
+    }
+
+    mbus_payload.insert(mbus_payload.end(), &this->receive_buffer_[frame_offset + MBUS_FULL_HEADER_LENGTH],
+                        &this->receive_buffer_[frame_offset + MBUS_HEADER_INTRO_LENGTH + frame_length]);
+
+    frame_offset += MBUS_HEADER_INTRO_LENGTH + frame_length + MBUS_FOOTER_LENGTH;
+  }
+  return true;
+}
+
+bool DlmsMeterComponent::parse_dlms_(const std::vector<uint8_t> &mbus_payload, uint16_t &message_length,
+                                     uint8_t &systitle_length, uint16_t &header_offset) {
+  ESP_LOGV(TAG, "Parsing DLMS header");
+  if (mbus_payload.size() < DLMS_HEADER_LENGTH + DLMS_HEADER_EXT_OFFSET) {
+    ESP_LOGE(TAG, "DLMS: Payload too short");
+    this->receive_buffer_.clear();
+    return false;
+  }
+
+  if (mbus_payload[DLMS_CIPHER_OFFSET] != GLO_CIPHERING) {  // Only general-glo-ciphering is supported (0xDB)
+    ESP_LOGE(TAG, "DLMS: Unsupported cipher");
+    this->receive_buffer_.clear();
+    return false;
+  }
+
+  systitle_length = mbus_payload[DLMS_SYST_OFFSET];
+
+  if (systitle_length != 0x08) {  // Only system titles with length of 8 are supported
+    ESP_LOGE(TAG, "DLMS: Unsupported system title length");
+    this->receive_buffer_.clear();
+    return false;
+  }
+
+  message_length = mbus_payload[DLMS_LENGTH_OFFSET];
+  header_offset = 0;
+
+  if (this->provider_ == PROVIDER_NETZNOE) {
+    // for some reason EVN seems to set the standard "length" field to 0x81 and then the actual length is in the next
+    // byte. Check some bytes to see if received data still matches expectation
+    if (message_length == NETZ_NOE_MAGIC_BYTE &&
+        mbus_payload[DLMS_LENGTH_OFFSET + 1] == NETZ_NOE_EXPECTED_MESSAGE_LENGTH &&
+        mbus_payload[DLMS_LENGTH_OFFSET + 2] == NETZ_NOE_EXPECTED_SECURITY_CONTROL_BYTE) {
+      message_length = mbus_payload[DLMS_LENGTH_OFFSET + 1];
+      header_offset = 1;
+    } else {
+      ESP_LOGE(TAG, "Wrong Length - Security Control Byte sequence detected for provider EVN");
+    }
+  } else {
+    if (message_length == TWO_BYTE_LENGTH) {
+      message_length = encode_uint16(mbus_payload[DLMS_LENGTH_OFFSET + 1], mbus_payload[DLMS_LENGTH_OFFSET + 2]);
+      header_offset = DLMS_HEADER_EXT_OFFSET;
+    }
+  }
+  if (message_length < DLMS_LENGTH_CORRECTION) {
+    ESP_LOGE(TAG, "DLMS: Message length too short: %u", message_length);
+    this->receive_buffer_.clear();
+    return false;
+  }
+  message_length -= DLMS_LENGTH_CORRECTION;  // Correct message length due to part of header being included in length
+
+  if (mbus_payload.size() - DLMS_HEADER_LENGTH - header_offset != message_length) {
+    ESP_LOGV(TAG, "DLMS: Length mismatch - payload=%d, header=%d, offset=%d, message=%d", mbus_payload.size(),
+             DLMS_HEADER_LENGTH, header_offset, message_length);
+    ESP_LOGE(TAG, "DLMS: Message has invalid length");
+    this->receive_buffer_.clear();
+    return false;
+  }
+
+  if (mbus_payload[header_offset + DLMS_SECBYTE_OFFSET] != 0x21 &&
+      mbus_payload[header_offset + DLMS_SECBYTE_OFFSET] !=
+          0x20) {  // Only certain security suite is supported (0x21 || 0x20)
+    ESP_LOGE(TAG, "DLMS: Unsupported security control byte");
+    this->receive_buffer_.clear();
+    return false;
+  }
+
+  return true;
+}
+
+bool DlmsMeterComponent::decrypt_(std::vector<uint8_t> &mbus_payload, uint16_t message_length, uint8_t systitle_length,
+                                  uint16_t header_offset) {
+  ESP_LOGV(TAG, "Decrypting payload");
+  uint8_t iv[12];  // Reserve space for the IV, always 12 bytes
+  // Copy system title to IV (System title is before length; no header offset needed!)
+  // Add 1 to the offset in order to skip the system title length byte
+  memcpy(&iv[0], &mbus_payload[DLMS_SYST_OFFSET + 1], systitle_length);
+  memcpy(&iv[8], &mbus_payload[header_offset + DLMS_FRAMECOUNTER_OFFSET],
+         DLMS_FRAMECOUNTER_LENGTH);  // Copy frame counter to IV
+
+  uint8_t *payload_ptr = &mbus_payload[header_offset + DLMS_PAYLOAD_OFFSET];
+
+#if defined(USE_ESP8266_FRAMEWORK_ARDUINO)
+  br_gcm_context gcm_ctx;
+  br_aes_ct_ctr_keys bc;
+  br_aes_ct_ctr_init(&bc, this->decryption_key_.data(), this->decryption_key_.size());
+  br_gcm_init(&gcm_ctx, &bc.vtable, br_ghash_ctmul32);
+  br_gcm_reset(&gcm_ctx, iv, sizeof(iv));
+  br_gcm_flip(&gcm_ctx);
+  br_gcm_run(&gcm_ctx, 0, payload_ptr, message_length);
+#elif defined(USE_ESP32)
+  size_t outlen = 0;
+  mbedtls_gcm_context gcm_ctx;
+  mbedtls_gcm_init(&gcm_ctx);
+  mbedtls_gcm_setkey(&gcm_ctx, MBEDTLS_CIPHER_ID_AES, this->decryption_key_.data(), this->decryption_key_.size() * 8);
+  mbedtls_gcm_starts(&gcm_ctx, MBEDTLS_GCM_DECRYPT, iv, sizeof(iv));
+  auto ret = mbedtls_gcm_update(&gcm_ctx, payload_ptr, message_length, payload_ptr, message_length, &outlen);
+  mbedtls_gcm_free(&gcm_ctx);
+  if (ret != 0) {
+    ESP_LOGE(TAG, "Decryption failed with error: %d", ret);
+    this->receive_buffer_.clear();
+    return false;
+  }
+#else
+#error "Invalid Platform"
+#endif
+
+  if (payload_ptr[0] != DATA_NOTIFICATION || payload_ptr[5] != TIMESTAMP_DATETIME) {
+    ESP_LOGE(TAG, "OBIS: Packet was decrypted but data is invalid");
+    this->receive_buffer_.clear();
+    return false;
+  }
+  ESP_LOGV(TAG, "Decrypted payload: %d bytes", message_length);
+  return true;
+}
+
+void DlmsMeterComponent::decode_obis_(uint8_t *plaintext, uint16_t message_length) {
+  ESP_LOGV(TAG, "Decoding payload");
+  MeterData data{};
+  uint16_t current_position = DECODER_START_OFFSET;
+  bool power_factor_found = false;
+
+  while (current_position + OBIS_CODE_OFFSET <= message_length) {
+    if (plaintext[current_position + OBIS_TYPE_OFFSET] != DataType::OCTET_STRING) {
+      ESP_LOGE(TAG, "OBIS: Unsupported OBIS header type: %x", plaintext[current_position + OBIS_TYPE_OFFSET]);
+      this->receive_buffer_.clear();
+      return;
+    }
+
+    uint8_t obis_code_length = plaintext[current_position + OBIS_LENGTH_OFFSET];
+    if (obis_code_length != OBIS_CODE_LENGTH_STANDARD && obis_code_length != OBIS_CODE_LENGTH_EXTENDED) {
+      ESP_LOGE(TAG, "OBIS: Unsupported OBIS header length: %x", obis_code_length);
+      this->receive_buffer_.clear();
+      return;
+    }
+    if (current_position + OBIS_CODE_OFFSET + obis_code_length > message_length) {
+      ESP_LOGE(TAG, "OBIS: Buffer too short for OBIS code");
+      this->receive_buffer_.clear();
+      return;
+    }
+
+    uint8_t *obis_code = &plaintext[current_position + OBIS_CODE_OFFSET];
+    uint8_t obis_medium = obis_code[OBIS_A];
+    uint16_t obis_cd = encode_uint16(obis_code[OBIS_C], obis_code[OBIS_D]);
+
+    bool timestamp_found = false;
+    bool meter_number_found = false;
+    if (this->provider_ == PROVIDER_NETZNOE) {
+      // Do not advance Position when reading the Timestamp at DECODER_START_OFFSET
+      if ((obis_code_length == OBIS_CODE_LENGTH_EXTENDED) && (current_position == DECODER_START_OFFSET)) {
+        timestamp_found = true;
+      } else if (power_factor_found) {
+        meter_number_found = true;
+        power_factor_found = false;
+      } else {
+        current_position += obis_code_length + OBIS_CODE_OFFSET;  // Advance past code and position
+      }
+    } else {
+      current_position += obis_code_length + OBIS_CODE_OFFSET;  // Advance past code, position and type
+    }
+    if (!timestamp_found && !meter_number_found && obis_medium != Medium::ELECTRICITY &&
+        obis_medium != Medium::ABSTRACT) {
+      ESP_LOGE(TAG, "OBIS: Unsupported OBIS medium: %x", obis_medium);
+      this->receive_buffer_.clear();
+      return;
+    }
+
+    if (current_position >= message_length) {
+      ESP_LOGE(TAG, "OBIS: Buffer too short for data type");
+      this->receive_buffer_.clear();
+      return;
+    }
+
+    float value = 0.0f;
+    uint8_t value_size = 0;
+    uint8_t data_type = plaintext[current_position];
+    current_position++;
+
+    switch (data_type) {
+      case DataType::DOUBLE_LONG_UNSIGNED: {
+        value_size = 4;
+        if (current_position + value_size > message_length) {
+          ESP_LOGE(TAG, "OBIS: Buffer too short for DOUBLE_LONG_UNSIGNED");
+          this->receive_buffer_.clear();
+          return;
+        }
+        value = encode_uint32(plaintext[current_position + 0], plaintext[current_position + 1],
+                              plaintext[current_position + 2], plaintext[current_position + 3]);
+        current_position += value_size;
+        break;
+      }
+      case DataType::LONG_UNSIGNED: {
+        value_size = 2;
+        if (current_position + value_size > message_length) {
+          ESP_LOGE(TAG, "OBIS: Buffer too short for LONG_UNSIGNED");
+          this->receive_buffer_.clear();
+          return;
+        }
+        value = encode_uint16(plaintext[current_position + 0], plaintext[current_position + 1]);
+        current_position += value_size;
+        break;
+      }
+      case DataType::OCTET_STRING: {
+        uint8_t data_length = plaintext[current_position];
+        current_position++;  // Advance past string length
+        if (current_position + data_length > message_length) {
+          ESP_LOGE(TAG, "OBIS: Buffer too short for OCTET_STRING");
+          this->receive_buffer_.clear();
+          return;
+        }
+        // Handle timestamp (normal OBIS code or NETZNOE special case)
+        if (obis_cd == OBIS_TIMESTAMP || timestamp_found) {
+          if (data_length < 8) {
+            ESP_LOGE(TAG, "OBIS: Timestamp data too short: %u", data_length);
+            this->receive_buffer_.clear();
+            return;
+          }
+          uint16_t year = encode_uint16(plaintext[current_position + 0], plaintext[current_position + 1]);
+          uint8_t month = plaintext[current_position + 2];
+          uint8_t day = plaintext[current_position + 3];
+          uint8_t hour = plaintext[current_position + 5];
+          uint8_t minute = plaintext[current_position + 6];
+          uint8_t second = plaintext[current_position + 7];
+          if (year > 9999 || month > 12 || day > 31 || hour > 23 || minute > 59 || second > 59) {
+            ESP_LOGE(TAG, "Invalid timestamp values: %04u-%02u-%02uT%02u:%02u:%02uZ", year, month, day, hour, minute,
+                     second);
+            this->receive_buffer_.clear();
+            return;
+          }
+          snprintf(data.timestamp, sizeof(data.timestamp), "%04u-%02u-%02uT%02u:%02u:%02uZ", year, month, day, hour,
+                   minute, second);
+        } else if (meter_number_found) {
+          snprintf(data.meternumber, sizeof(data.meternumber), "%.*s", data_length, &plaintext[current_position]);
+        }
+        current_position += data_length;
+        break;
+      }
+      default:
+        ESP_LOGE(TAG, "OBIS: Unsupported OBIS data type: %x", data_type);
+        this->receive_buffer_.clear();
+        return;
+    }
+
+    // Skip break after data
+    if (this->provider_ == PROVIDER_NETZNOE) {
+      // Don't skip the break on the first timestamp, as there's none
+      if (!timestamp_found) {
+        current_position += 2;
+      }
+    } else {
+      current_position += 2;
+    }
+
+    // Check for additional data (scaler-unit structure)
+    if (current_position < message_length && plaintext[current_position] == DataType::INTEGER) {
+      // Apply scaler: real_value = raw_value × 10^scaler
+      if (current_position + 1 < message_length) {
+        int8_t scaler = static_cast<int8_t>(plaintext[current_position + 1]);
+        if (scaler != 0) {
+          value *= powf(10.0f, scaler);
+        }
+      }
+
+      // on EVN Meters there is no additional break
+      if (this->provider_ == PROVIDER_NETZNOE) {
+        current_position += 4;
+      } else {
+        current_position += 6;
+      }
+    }
+
+    // Handle numeric values (LONG_UNSIGNED and DOUBLE_LONG_UNSIGNED)
+    if (value_size > 0) {
+      switch (obis_cd) {
+        case OBIS_VOLTAGE_L1:
+          data.voltage_l1 = value;
+          break;
+        case OBIS_VOLTAGE_L2:
+          data.voltage_l2 = value;
+          break;
+        case OBIS_VOLTAGE_L3:
+          data.voltage_l3 = value;
+          break;
+        case OBIS_CURRENT_L1:
+          data.current_l1 = value;
+          break;
+        case OBIS_CURRENT_L2:
+          data.current_l2 = value;
+          break;
+        case OBIS_CURRENT_L3:
+          data.current_l3 = value;
+          break;
+        case OBIS_ACTIVE_POWER_PLUS:
+          data.active_power_plus = value;
+          break;
+        case OBIS_ACTIVE_POWER_MINUS:
+          data.active_power_minus = value;
+          break;
+        case OBIS_ACTIVE_ENERGY_PLUS:
+          data.active_energy_plus = value;
+          break;
+        case OBIS_ACTIVE_ENERGY_MINUS:
+          data.active_energy_minus = value;
+          break;
+        case OBIS_REACTIVE_ENERGY_PLUS:
+          data.reactive_energy_plus = value;
+          break;
+        case OBIS_REACTIVE_ENERGY_MINUS:
+          data.reactive_energy_minus = value;
+          break;
+        case OBIS_POWER_FACTOR:
+          data.power_factor = value;
+          power_factor_found = true;
+          break;
+        default:
+          ESP_LOGW(TAG, "Unsupported OBIS code 0x%04X", obis_cd);
+      }
+    }
+  }
+
+  this->receive_buffer_.clear();
+
+  ESP_LOGI(TAG, "Received valid data");
+  this->publish_sensors(data);
+  this->status_clear_warning();
+}
+
+}  // namespace esphome::dlms_meter

esphome/components/dlms_meter/dlms_meter.h

@@ -0,0 +1,96 @@
+#pragma once
+
+#include "esphome/core/component.h"
+#include "esphome/core/defines.h"
+#include "esphome/core/log.h"
+#ifdef USE_SENSOR
+#include "esphome/components/sensor/sensor.h"
+#endif
+#ifdef USE_TEXT_SENSOR
+#include "esphome/components/text_sensor/text_sensor.h"
+#endif
+#include "esphome/components/uart/uart.h"
+
+#include "mbus.h"
+#include "dlms.h"
+#include "obis.h"
+
+#include <array>
+#include <vector>
+
+namespace esphome::dlms_meter {
+
+#ifndef DLMS_METER_SENSOR_LIST
+#define DLMS_METER_SENSOR_LIST(F, SEP)
+#endif
+
+#ifndef DLMS_METER_TEXT_SENSOR_LIST
+#define DLMS_METER_TEXT_SENSOR_LIST(F, SEP)
+#endif
+
+struct MeterData {
+  float voltage_l1 = 0.0f;             // Voltage L1
+  float voltage_l2 = 0.0f;             // Voltage L2
+  float voltage_l3 = 0.0f;             // Voltage L3
+  float current_l1 = 0.0f;             // Current L1
+  float current_l2 = 0.0f;             // Current L2
+  float current_l3 = 0.0f;             // Current L3
+  float active_power_plus = 0.0f;      // Active power taken from grid
+  float active_power_minus = 0.0f;     // Active power put into grid
+  float active_energy_plus = 0.0f;     // Active energy taken from grid
+  float active_energy_minus = 0.0f;    // Active energy put into grid
+  float reactive_energy_plus = 0.0f;   // Reactive energy taken from grid
+  float reactive_energy_minus = 0.0f;  // Reactive energy put into grid
+  char timestamp[27]{};                // Text sensor for the timestamp value
+
+  // Netz NOE
+  float power_factor = 0.0f;  // Power Factor
+  char meternumber[13]{};     // Text sensor for the meterNumber value
+};
+
+// Provider constants
+enum Providers : uint32_t { PROVIDER_GENERIC = 0x00, PROVIDER_NETZNOE = 0x01 };
+
+class DlmsMeterComponent : public Component, public uart::UARTDevice {
+ public:
+  DlmsMeterComponent() = default;
+
+  void dump_config() override;
+  void loop() override;
+
+  void set_decryption_key(const std::array<uint8_t, 16> &key) { this->decryption_key_ = key; }
+  void set_provider(uint32_t provider) { this->provider_ = provider; }
+
+  void publish_sensors(MeterData &data) {
+#define DLMS_METER_PUBLISH_SENSOR(s) \
+  if (this->s##_sensor_ != nullptr) \
+    s##_sensor_->publish_state(data.s);
+    DLMS_METER_SENSOR_LIST(DLMS_METER_PUBLISH_SENSOR, )
+
+#define DLMS_METER_PUBLISH_TEXT_SENSOR(s) \
+  if (this->s##_text_sensor_ != nullptr) \
+    s##_text_sensor_->publish_state(data.s);
+    DLMS_METER_TEXT_SENSOR_LIST(DLMS_METER_PUBLISH_TEXT_SENSOR, )
+  }
+
+  DLMS_METER_SENSOR_LIST(SUB_SENSOR, )
+  DLMS_METER_TEXT_SENSOR_LIST(SUB_TEXT_SENSOR, )
+
+ protected:
+  bool parse_mbus_(std::vector<uint8_t> &mbus_payload);
+  bool parse_dlms_(const std::vector<uint8_t> &mbus_payload, uint16_t &message_length, uint8_t &systitle_length,
+                   uint16_t &header_offset);
+  bool decrypt_(std::vector<uint8_t> &mbus_payload, uint16_t message_length, uint8_t systitle_length,
+                uint16_t header_offset);
+  void decode_obis_(uint8_t *plaintext, uint16_t message_length);
+
+  std::vector<uint8_t> receive_buffer_;  // Stores the packet currently being received
+  std::vector<uint8_t> mbus_payload_;    // Parsed M-Bus payload, reused to avoid heap churn
+  uint32_t last_read_ = 0;               // Timestamp when data was last read
+  uint32_t read_timeout_ = 1000;         // Time to wait after last byte before considering data complete
+
+  uint32_t provider_ = PROVIDER_GENERIC;  // Provider of the meter / your grid operator
+  std::array<uint8_t, 16> decryption_key_;
+};
+
+}  // namespace esphome::dlms_meter

esphome/components/dlms_meter/mbus.h

@@ -0,0 +1,69 @@
+#pragma once
+
+#include <cstdint>
+
+namespace esphome::dlms_meter {
+
+/*
++----------------------------------------------------+ -
+|               Start Character [0x68]               |  \
++----------------------------------------------------+   |
+|                   Data Length (L)                  |   |
++----------------------------------------------------+   |
+|               Data Length Repeat (L)               |   |
++----------------------------------------------------+    > M-Bus Data link layer
+|            Start Character Repeat [0x68]           |   |
++----------------------------------------------------+   |
+|             Control/Function Field (C)             |   |
++----------------------------------------------------+   |
+|                  Address Field (A)                 |  /
++----------------------------------------------------+ -
+|           Control Information Field (CI)           |  \
++----------------------------------------------------+   |
+|    Source Transport Service Access Point (STSAP)   |    > DLMS/COSEM M-Bus transport layer
++----------------------------------------------------+   |
+| Destination Transport Service Access Point (DTSAP) |  /
++----------------------------------------------------+ -
+|                                                    |  \
+~                                                    ~   |
+                         Data                             > DLMS/COSEM Application Layer
+~                                                    ~   |
+|                                                    |  /
++----------------------------------------------------+ -
+|                      Checksum                      |  \
++----------------------------------------------------+    > M-Bus Data link layer
+|                Stop Character [0x16]               |  /
++----------------------------------------------------+ -
+
+Data_Length = L - C - A - CI
+Each line (except Data) is one Byte
+
+Possible Values found in publicly available docs:
+- C: 0x53/0x73 (SND_UD)
+- A: FF (Broadcast)
+- CI: 0x00-0x1F/0x60/0x61/0x7C/0x7D
+- STSAP: 0x01 (Management Logical Device ID 1 of the meter)
+- DTSAP: 0x67 (Consumer Information Push Client ID 103)
+ */
+
+// MBUS start bytes for different telegram formats:
+// - Single Character: 0xE5 (length=1)
+// - Short Frame: 0x10 (length=5)
+// - Control Frame: 0x68 (length=9)
+// - Long Frame: 0x68 (length=9+data_length)
+// This component currently only uses Long Frame.
+static constexpr uint8_t START_BYTE_SINGLE_CHARACTER = 0xE5;
+static constexpr uint8_t START_BYTE_SHORT_FRAME = 0x10;
+static constexpr uint8_t START_BYTE_CONTROL_FRAME = 0x68;
+static constexpr uint8_t START_BYTE_LONG_FRAME = 0x68;
+static constexpr uint8_t MBUS_HEADER_INTRO_LENGTH = 4;  // Header length for the intro (0x68, length, length, 0x68)
+static constexpr uint8_t MBUS_FULL_HEADER_LENGTH = 9;   // Total header length
+static constexpr uint8_t MBUS_FOOTER_LENGTH = 2;        // Footer after frame
+static constexpr uint8_t MBUS_MAX_FRAME_LENGTH = 250;   // Maximum size of frame
+static constexpr uint8_t MBUS_START1_OFFSET = 0;        // Offset of first start byte
+static constexpr uint8_t MBUS_LENGTH1_OFFSET = 1;       // Offset of first length byte
+static constexpr uint8_t MBUS_LENGTH2_OFFSET = 2;       // Offset of (duplicated) second length byte
+static constexpr uint8_t MBUS_START2_OFFSET = 3;        // Offset of (duplicated) second start byte
+static constexpr uint8_t STOP_BYTE = 0x16;
+
+}  // namespace esphome::dlms_meter

esphome/components/dlms_meter/obis.h

@@ -0,0 +1,94 @@
+#pragma once
+
+#include <cstdint>
+
+namespace esphome::dlms_meter {
+
+// Data types as per specification
+enum DataType {
+  NULL_DATA = 0x00,
+  BOOLEAN = 0x03,
+  BIT_STRING = 0x04,
+  DOUBLE_LONG = 0x05,
+  DOUBLE_LONG_UNSIGNED = 0x06,
+  OCTET_STRING = 0x09,
+  VISIBLE_STRING = 0x0A,
+  UTF8_STRING = 0x0C,
+  BINARY_CODED_DECIMAL = 0x0D,
+  INTEGER = 0x0F,
+  LONG = 0x10,
+  UNSIGNED = 0x11,
+  LONG_UNSIGNED = 0x12,
+  LONG64 = 0x14,
+  LONG64_UNSIGNED = 0x15,
+  ENUM = 0x16,
+  FLOAT32 = 0x17,
+  FLOAT64 = 0x18,
+  DATE_TIME = 0x19,
+  DATE = 0x1A,
+  TIME = 0x1B,
+
+  ARRAY = 0x01,
+  STRUCTURE = 0x02,
+  COMPACT_ARRAY = 0x13
+};
+
+enum Medium {
+  ABSTRACT = 0x00,
+  ELECTRICITY = 0x01,
+  HEAT_COST_ALLOCATOR = 0x04,
+  COOLING = 0x05,
+  HEAT = 0x06,
+  GAS = 0x07,
+  COLD_WATER = 0x08,
+  HOT_WATER = 0x09,
+  OIL = 0x10,
+  COMPRESSED_AIR = 0x11,
+  NITROGEN = 0x12
+};
+
+// Data structure
+static constexpr uint8_t DECODER_START_OFFSET = 20;  // Skip header, timestamp and break block
+static constexpr uint8_t OBIS_TYPE_OFFSET = 0;
+static constexpr uint8_t OBIS_LENGTH_OFFSET = 1;
+static constexpr uint8_t OBIS_CODE_OFFSET = 2;
+static constexpr uint8_t OBIS_CODE_LENGTH_STANDARD = 0x06;  // 6-byte OBIS code (A.B.C.D.E.F)
+static constexpr uint8_t OBIS_CODE_LENGTH_EXTENDED = 0x0C;  // 12-byte extended OBIS code
+static constexpr uint8_t OBIS_A = 0;
+static constexpr uint8_t OBIS_B = 1;
+static constexpr uint8_t OBIS_C = 2;
+static constexpr uint8_t OBIS_D = 3;
+static constexpr uint8_t OBIS_E = 4;
+static constexpr uint8_t OBIS_F = 5;
+
+// Metadata
+static constexpr uint16_t OBIS_TIMESTAMP = 0x0100;
+static constexpr uint16_t OBIS_SERIAL_NUMBER = 0x6001;
+static constexpr uint16_t OBIS_DEVICE_NAME = 0x2A00;
+
+// Voltage
+static constexpr uint16_t OBIS_VOLTAGE_L1 = 0x2007;
+static constexpr uint16_t OBIS_VOLTAGE_L2 = 0x3407;
+static constexpr uint16_t OBIS_VOLTAGE_L3 = 0x4807;
+
+// Current
+static constexpr uint16_t OBIS_CURRENT_L1 = 0x1F07;
+static constexpr uint16_t OBIS_CURRENT_L2 = 0x3307;
+static constexpr uint16_t OBIS_CURRENT_L3 = 0x4707;
+
+// Power
+static constexpr uint16_t OBIS_ACTIVE_POWER_PLUS = 0x0107;
+static constexpr uint16_t OBIS_ACTIVE_POWER_MINUS = 0x0207;
+
+// Active energy
+static constexpr uint16_t OBIS_ACTIVE_ENERGY_PLUS = 0x0108;
+static constexpr uint16_t OBIS_ACTIVE_ENERGY_MINUS = 0x0208;
+
+// Reactive energy
+static constexpr uint16_t OBIS_REACTIVE_ENERGY_PLUS = 0x0308;
+static constexpr uint16_t OBIS_REACTIVE_ENERGY_MINUS = 0x0408;
+
+// Netz NOE specific
+static constexpr uint16_t OBIS_POWER_FACTOR = 0x0D07;
+
+}  // namespace esphome::dlms_meter

esphome/components/dlms_meter/sensor/__init__.py

@@ -0,0 +1,124 @@
+import esphome.codegen as cg
+from esphome.components import sensor
+import esphome.config_validation as cv
+from esphome.const import (
+    CONF_ID,
+    DEVICE_CLASS_CURRENT,
+    DEVICE_CLASS_ENERGY,
+    DEVICE_CLASS_POWER,
+    DEVICE_CLASS_POWER_FACTOR,
+    DEVICE_CLASS_VOLTAGE,
+    STATE_CLASS_MEASUREMENT,
+    STATE_CLASS_TOTAL_INCREASING,
+    UNIT_AMPERE,
+    UNIT_VOLT,
+    UNIT_WATT,
+    UNIT_WATT_HOURS,
+)
+
+from .. import CONF_DLMS_METER_ID, DlmsMeterComponent
+
+AUTO_LOAD = ["dlms_meter"]
+
+CONFIG_SCHEMA = cv.Schema(
+    {
+        cv.GenerateID(CONF_DLMS_METER_ID): cv.use_id(DlmsMeterComponent),
+        cv.Optional("voltage_l1"): sensor.sensor_schema(
+            unit_of_measurement=UNIT_VOLT,
+            accuracy_decimals=1,
+            device_class=DEVICE_CLASS_VOLTAGE,
+            state_class=STATE_CLASS_MEASUREMENT,
+        ),
+        cv.Optional("voltage_l2"): sensor.sensor_schema(
+            unit_of_measurement=UNIT_VOLT,
+            accuracy_decimals=1,
+            device_class=DEVICE_CLASS_VOLTAGE,
+            state_class=STATE_CLASS_MEASUREMENT,
+        ),
+        cv.Optional("voltage_l3"): sensor.sensor_schema(
+            unit_of_measurement=UNIT_VOLT,
+            accuracy_decimals=1,
+            device_class=DEVICE_CLASS_VOLTAGE,
+            state_class=STATE_CLASS_MEASUREMENT,
+        ),
+        cv.Optional("current_l1"): sensor.sensor_schema(
+            unit_of_measurement=UNIT_AMPERE,
+            accuracy_decimals=2,
+            device_class=DEVICE_CLASS_CURRENT,
+            state_class=STATE_CLASS_MEASUREMENT,
+        ),
+        cv.Optional("current_l2"): sensor.sensor_schema(
+            unit_of_measurement=UNIT_AMPERE,
+            accuracy_decimals=2,
+            device_class=DEVICE_CLASS_CURRENT,
+            state_class=STATE_CLASS_MEASUREMENT,
+        ),
+        cv.Optional("current_l3"): sensor.sensor_schema(
+            unit_of_measurement=UNIT_AMPERE,
+            accuracy_decimals=2,
+            device_class=DEVICE_CLASS_CURRENT,
+            state_class=STATE_CLASS_MEASUREMENT,
+        ),
+        cv.Optional("active_power_plus"): sensor.sensor_schema(
+            unit_of_measurement=UNIT_WATT,
+            accuracy_decimals=0,
+            device_class=DEVICE_CLASS_POWER,
+            state_class=STATE_CLASS_MEASUREMENT,
+        ),
+        cv.Optional("active_power_minus"): sensor.sensor_schema(
+            unit_of_measurement=UNIT_WATT,
+            accuracy_decimals=0,
+            device_class=DEVICE_CLASS_POWER,
+            state_class=STATE_CLASS_MEASUREMENT,
+        ),
+        cv.Optional("active_energy_plus"): sensor.sensor_schema(
+            unit_of_measurement=UNIT_WATT_HOURS,
+            accuracy_decimals=0,
+            device_class=DEVICE_CLASS_ENERGY,
+            state_class=STATE_CLASS_TOTAL_INCREASING,
+        ),
+        cv.Optional("active_energy_minus"): sensor.sensor_schema(
+            unit_of_measurement=UNIT_WATT_HOURS,
+            accuracy_decimals=0,
+            device_class=DEVICE_CLASS_ENERGY,
+            state_class=STATE_CLASS_TOTAL_INCREASING,
+        ),
+        cv.Optional("reactive_energy_plus"): sensor.sensor_schema(
+            unit_of_measurement=UNIT_WATT_HOURS,
+            accuracy_decimals=0,
+            device_class=DEVICE_CLASS_ENERGY,
+            state_class=STATE_CLASS_TOTAL_INCREASING,
+        ),
+        cv.Optional("reactive_energy_minus"): sensor.sensor_schema(
+            unit_of_measurement=UNIT_WATT_HOURS,
+            accuracy_decimals=0,
+            device_class=DEVICE_CLASS_ENERGY,
+            state_class=STATE_CLASS_TOTAL_INCREASING,
+        ),
+        # Netz NOE
+        cv.Optional("power_factor"): sensor.sensor_schema(
+            accuracy_decimals=3,
+            device_class=DEVICE_CLASS_POWER_FACTOR,
+            state_class=STATE_CLASS_MEASUREMENT,
+        ),
+    }
+).extend(cv.COMPONENT_SCHEMA)
+
+
+async def to_code(config):
+    hub = await cg.get_variable(config[CONF_DLMS_METER_ID])
+
+    sensors = []
+    for key, conf in config.items():
+        if not isinstance(conf, dict):
+            continue
+        id = conf[CONF_ID]
+        if id and id.type == sensor.Sensor:
+            sens = await sensor.new_sensor(conf)
+            cg.add(getattr(hub, f"set_{key}_sensor")(sens))
+            sensors.append(f"F({key})")
+
+    if sensors:
+        cg.add_define(
+            "DLMS_METER_SENSOR_LIST(F, sep)", cg.RawExpression(" sep ".join(sensors))
+        )

esphome/components/dlms_meter/text_sensor/__init__.py

@@ -0,0 +1,37 @@
+import esphome.codegen as cg
+from esphome.components import text_sensor
+import esphome.config_validation as cv
+from esphome.const import CONF_ID
+
+from .. import CONF_DLMS_METER_ID, DlmsMeterComponent
+
+AUTO_LOAD = ["dlms_meter"]
+
+CONFIG_SCHEMA = cv.Schema(
+    {
+        cv.GenerateID(CONF_DLMS_METER_ID): cv.use_id(DlmsMeterComponent),
+        cv.Optional("timestamp"): text_sensor.text_sensor_schema(),
+        # Netz NOE
+        cv.Optional("meternumber"): text_sensor.text_sensor_schema(),
+    }
+).extend(cv.COMPONENT_SCHEMA)
+
+
+async def to_code(config):
+    hub = await cg.get_variable(config[CONF_DLMS_METER_ID])
+
+    text_sensors = []
+    for key, conf in config.items():
+        if not isinstance(conf, dict):
+            continue
+        id = conf[CONF_ID]
+        if id and id.type == text_sensor.TextSensor:
+            sens = await text_sensor.new_text_sensor(conf)
+            cg.add(getattr(hub, f"set_{key}_text_sensor")(sens))
+            text_sensors.append(f"F({key})")
+
+    if text_sensors:
+        cg.add_define(
+            "DLMS_METER_TEXT_SENSOR_LIST(F, sep)",
+            cg.RawExpression(" sep ".join(text_sensors)),
+        )

esphome/components/esp32/__init__.py

@@ -1287,6 +1287,18 @@ async def to_code(config):
     # Increase freertos tick speed from 100Hz to 1kHz so that delay() resolution is 1ms
     add_idf_sdkconfig_option("CONFIG_FREERTOS_HZ", 1000)
 
+    # Reduce FreeRTOS max priorities from 25 to 16 to save RAM
+    # pxReadyTasksLists uses 20 bytes per priority level, so this saves 180 bytes
+    # All ESPHome tasks use relative priorities (configMAX_PRIORITIES - X) to scale automatically
+    # See https://github.com/espressif/esp-idf/issues/13041 for context
+    add_idf_sdkconfig_option("CONFIG_FREERTOS_MAX_PRIORITIES", 16)
+
+    # Set LWIP TCP/IP task priority to fit within reduced priority range (0-15)
+    # Default is 18, which would be invalid with MAX_PRIORITIES=16
+    # Priority 8 maintains the original hierarchy: I2S speaker (10) > LWIP (8) > mixer (6)
+    # This ensures audio I/O tasks aren't blocked by network, while network isn't starved by mixing
+    add_idf_sdkconfig_option("CONFIG_LWIP_TCPIP_TASK_PRIO", 8)
+
     # Place non-ISR FreeRTOS functions into flash instead of IRAM
     # This saves up to 8KB of IRAM. ISR-safe functions (FromISR variants) stay in IRAM.
     # In ESP-IDF 6.0 this becomes the default and CONFIG_FREERTOS_PLACE_FUNCTIONS_INTO_FLASH
@@ -1329,6 +1341,10 @@ async def to_code(config):
     # Disable dynamic log level control to save memory
     add_idf_sdkconfig_option("CONFIG_LOG_DYNAMIC_LEVEL_CONTROL", False)
 
+    # Disable per-tag log level filtering since dynamic level control is disabled above
+    # This saves ~250 bytes of RAM (tag cache) and associated code
+    add_idf_sdkconfig_option("CONFIG_LOG_TAG_LEVEL_IMPL_NONE", True)
+
     # Reduce PHY TX power in the event of a brownout
     add_idf_sdkconfig_option("CONFIG_ESP_PHY_REDUCE_TX_POWER", True)
 

esphome/components/esp32/core.cpp

@@ -3,6 +3,7 @@
 #include "esphome/core/defines.h"
 #include "esphome/core/hal.h"
 #include "esphome/core/helpers.h"
+#include "esphome/core/task_priorities.h"
 #include "preferences.h"
 #include <esp_clk_tree.h>
 #include <esp_cpu.h>
@@ -66,10 +67,14 @@ void loop_task(void *pv_params) {
 extern "C" void app_main() {
   initArduino();
   esp32::setup_preferences();
+  // TASK_PRIORITY_APPLICATION: baseline priority for main loop - all component loops
+  // run here. Higher priority tasks (audio, network) preempt this when needed.
 #if CONFIG_FREERTOS_UNICORE
-  xTaskCreate(loop_task, "loopTask", ESPHOME_LOOP_TASK_STACK_SIZE, nullptr, 1, &loop_task_handle);
+  xTaskCreate(loop_task, "loopTask", ESPHOME_LOOP_TASK_STACK_SIZE, nullptr, TASK_PRIORITY_APPLICATION,
+              &loop_task_handle);
 #else
-  xTaskCreatePinnedToCore(loop_task, "loopTask", ESPHOME_LOOP_TASK_STACK_SIZE, nullptr, 1, &loop_task_handle, 1);
+  xTaskCreatePinnedToCore(loop_task, "loopTask", ESPHOME_LOOP_TASK_STACK_SIZE, nullptr, TASK_PRIORITY_APPLICATION,
+                          &loop_task_handle, 1);
 #endif
 }
 

esphome/components/esp32_camera/esp32_camera.cpp

@@ -4,6 +4,7 @@
 #include "esphome/core/application.h"
 #include "esphome/core/hal.h"
 #include "esphome/core/log.h"
+#include "esphome/core/task_priorities.h"
 
 #include <freertos/task.h>
 
@@ -42,11 +43,13 @@ void ESP32Camera::setup() {
   /* initialize RTOS */
   this->framebuffer_get_queue_ = xQueueCreate(1, sizeof(camera_fb_t *));
   this->framebuffer_return_queue_ = xQueueCreate(1, sizeof(camera_fb_t *));
+  // TASK_PRIORITY_APPLICATION: same as main loop - camera capture is buffered,
+  // not real-time critical like audio
   xTaskCreatePinnedToCore(&ESP32Camera::framebuffer_task,
                           "framebuffer_task",           // name
                           FRAMEBUFFER_TASK_STACK_SIZE,  // stack size
                           this,                         // task pv params
-                          1,                            // priority
+                          TASK_PRIORITY_APPLICATION,    // priority
                           nullptr,                      // handle
                           1                             // core
   );

esphome/components/esp32_hosted/update/esp32_hosted_update.cpp

@@ -34,29 +34,14 @@ static const char *const ESP_HOSTED_VERSION_STR = STRINGIFY(ESP_HOSTED_VERSION_M
     ESP_HOSTED_VERSION_MINOR_1) "." STRINGIFY(ESP_HOSTED_VERSION_PATCH_1);
 
 #ifdef USE_ESP32_HOSTED_HTTP_UPDATE
-// Parse an integer from str, advancing ptr past the number
-// Returns false if no digits were parsed
-static bool parse_int(const char *&ptr, int &value) {
-  char *end;
-  value = static_cast<int>(strtol(ptr, &end, 10));
-  if (end == ptr)
-    return false;
-  ptr = end;
-  return true;
-}
-
 // Parse version string "major.minor.patch" into components
-// Returns true if at least major.minor was parsed
+// Returns true if parsing succeeded
 static bool parse_version(const std::string &version_str, int &major, int &minor, int &patch) {
   major = minor = patch = 0;
-  const char *ptr = version_str.c_str();
-
-  if (!parse_int(ptr, major) || *ptr++ != '.' || !parse_int(ptr, minor))
-    return false;
-  if (*ptr == '.')
-    parse_int(++ptr, patch);
-
-  return true;
+  if (sscanf(version_str.c_str(), "%d.%d.%d", &major, &minor, &patch) >= 2) {
+    return true;
+  }
+  return false;
 }
 
 // Compare two versions, returns:

esphome/components/http_request/update/http_request_update.cpp

@@ -2,6 +2,9 @@
 
 #include "esphome/core/application.h"
 #include "esphome/core/version.h"
+#ifdef USE_ESP32
+#include "esphome/core/task_priorities.h"
+#endif
 
 #include "esphome/components/json/json_util.h"
 #include "esphome/components/network/util.h"
@@ -46,7 +49,9 @@ void HttpRequestUpdate::update() {
     return;
   }
 #ifdef USE_ESP32
-  xTaskCreate(HttpRequestUpdate::update_task, "update_task", 8192, (void *) this, 1, &this->update_task_handle_);
+  // TASK_PRIORITY_APPLICATION: same as main loop - update check is background work
+  xTaskCreate(HttpRequestUpdate::update_task, "update_task", 8192, (void *) this, TASK_PRIORITY_APPLICATION,
+              &this->update_task_handle_);
 #else
   this->update_task(this);
 #endif

esphome/components/i2c/i2c.cpp

@@ -11,12 +11,6 @@ namespace i2c {
 static const char *const TAG = "i2c";
 
 void I2CBus::i2c_scan_() {
-  // suppress logs from the IDF I2C library during the scan
-#if defined(USE_ESP32) && defined(USE_LOGGER)
-  auto previous = esp_log_level_get("*");
-  esp_log_level_set("*", ESP_LOG_NONE);
-#endif
-
   for (uint8_t address = 8; address != 120; address++) {
     auto err = write_readv(address, nullptr, 0, nullptr, 0);
     if (err == ERROR_OK) {
@@ -27,9 +21,6 @@ void I2CBus::i2c_scan_() {
     // it takes 16sec to scan on nrf52. It prevents board reset.
     arch_feed_wdt();
   }
-#if defined(USE_ESP32) && defined(USE_LOGGER)
-  esp_log_level_set("*", previous);
-#endif
 }
 
 ErrorCode I2CDevice::read_register(uint8_t a_register, uint8_t *data, size_t len) {

esphome/components/i2s_audio/microphone/i2s_audio_microphone.cpp

@@ -11,6 +11,7 @@
 
 #include "esphome/core/hal.h"
 #include "esphome/core/log.h"
+#include "esphome/core/task_priorities.h"
 
 #include "esphome/components/audio/audio.h"
 
@@ -22,7 +23,6 @@ static const UBaseType_t MAX_LISTENERS = 16;
 static const uint32_t READ_DURATION_MS = 16;
 
 static const size_t TASK_STACK_SIZE = 4096;
-static const ssize_t TASK_PRIORITY = 23;
 
 static const char *const TAG = "i2s_audio.microphone";
 
@@ -520,8 +520,10 @@ void I2SAudioMicrophone::loop() {
       }
 
       if (this->task_handle_ == nullptr) {
-        xTaskCreate(I2SAudioMicrophone::mic_task, "mic_task", TASK_STACK_SIZE, (void *) this, TASK_PRIORITY,
-                    &this->task_handle_);
+        // TASK_PRIORITY_AUDIO_CAPTURE: highest application priority - real-time audio
+        // input cannot tolerate delays without dropping samples
+        xTaskCreate(I2SAudioMicrophone::mic_task, "mic_task", TASK_STACK_SIZE, (void *) this,
+                    TASK_PRIORITY_AUDIO_CAPTURE, &this->task_handle_);
 
         if (this->task_handle_ == nullptr) {
           ESP_LOGE(TAG, "Task failed to start, retrying in 1 second");

esphome/components/i2s_audio/speaker/i2s_audio_speaker.cpp

@@ -14,6 +14,7 @@
 #include "esphome/core/application.h"
 #include "esphome/core/hal.h"
 #include "esphome/core/log.h"
+#include "esphome/core/task_priorities.h"
 
 #include "esp_timer.h"
 
@@ -24,7 +25,6 @@ static const uint32_t DMA_BUFFER_DURATION_MS = 15;
 static const size_t DMA_BUFFERS_COUNT = 4;
 
 static const size_t TASK_STACK_SIZE = 4096;
-static const ssize_t TASK_PRIORITY = 19;
 
 static const size_t I2S_EVENT_QUEUE_COUNT = DMA_BUFFERS_COUNT + 1;
 
@@ -151,8 +151,10 @@ void I2SAudioSpeaker::loop() {
       }
 
       if (this->speaker_task_handle_ == nullptr) {
-        xTaskCreate(I2SAudioSpeaker::speaker_task, "speaker_task", TASK_STACK_SIZE, (void *) this, TASK_PRIORITY,
-                    &this->speaker_task_handle_);
+        // TASK_PRIORITY_AUDIO_OUTPUT: high priority for real-time audio output,
+        // below capture (TASK_PRIORITY_AUDIO_CAPTURE) but above network tasks
+        xTaskCreate(I2SAudioSpeaker::speaker_task, "speaker_task", TASK_STACK_SIZE, (void *) this,
+                    TASK_PRIORITY_AUDIO_OUTPUT, &this->speaker_task_handle_);
 
         if (this->speaker_task_handle_ == nullptr) {
           ESP_LOGE(TAG, "Task failed to start, retrying in 1 second");

esphome/components/logger/logger_esp32.cpp

@@ -114,9 +114,6 @@ void Logger::pre_setup() {
 
   global_logger = this;
   esp_log_set_vprintf(esp_idf_log_vprintf_);
-  if (ESPHOME_LOG_LEVEL >= ESPHOME_LOG_LEVEL_VERBOSE) {
-    esp_log_level_set("*", ESP_LOG_VERBOSE);
-  }
 
   ESP_LOGI(TAG, "Log initialized");
 }

esphome/components/max7219/display.py

@@ -28,11 +28,10 @@ CONFIG_SCHEMA = (
 
 
 async def to_code(config):
-    var = cg.new_Pvariable(config[CONF_ID])
+    var = cg.new_Pvariable(config[CONF_ID], config[CONF_NUM_CHIPS])
     await spi.register_spi_device(var, config, write_only=True)
     await display.register_display(var, config)
 
-    cg.add(var.set_num_chips(config[CONF_NUM_CHIPS]))
     cg.add(var.set_intensity(config[CONF_INTENSITY]))
     cg.add(var.set_reverse(config[CONF_REVERSE_ENABLE]))
 

esphome/components/max7219/max7219.cpp

@@ -3,8 +3,7 @@
 #include "esphome/core/helpers.h"
 #include "esphome/core/log.h"
 
-namespace esphome {
-namespace max7219 {
+namespace esphome::max7219 {
 
 static const char *const TAG = "max7219";
 
@@ -115,12 +114,14 @@ const uint8_t MAX7219_ASCII_TO_RAW[95] PROGMEM = {
 };
 
 float MAX7219Component::get_setup_priority() const { return setup_priority::PROCESSOR; }
+
+MAX7219Component::MAX7219Component(uint8_t num_chips) : num_chips_(num_chips) {
+  this->buffer_ = new uint8_t[this->num_chips_ * 8];  // NOLINT
+  memset(this->buffer_, 0, this->num_chips_ * 8);
+}
+
 void MAX7219Component::setup() {
   this->spi_setup();
-  this->buffer_ = new uint8_t[this->num_chips_ * 8];  // NOLINT
-  for (uint8_t i = 0; i < this->num_chips_ * 8; i++)
-    this->buffer_[i] = 0;
-
   // let's assume the user has all 8 digits connected, only important in daisy chained setups anyway
   this->send_to_all_(MAX7219_REGISTER_SCAN_LIMIT, 7);
   // let's use our own ASCII -> led pattern encoding
@@ -229,7 +230,6 @@ void MAX7219Component::set_intensity(uint8_t intensity) {
     this->intensity_ = intensity;
   }
 }
-void MAX7219Component::set_num_chips(uint8_t num_chips) { this->num_chips_ = num_chips; }
 
 uint8_t MAX7219Component::strftime(uint8_t pos, const char *format, ESPTime time) {
   char buffer[64];
@@ -240,5 +240,4 @@ uint8_t MAX7219Component::strftime(uint8_t pos, const char *format, ESPTime time
 }
 uint8_t MAX7219Component::strftime(const char *format, ESPTime time) { return this->strftime(0, format, time); }
 
-}  // namespace max7219
-}  // namespace esphome
+}  // namespace esphome::max7219

esphome/components/max7219/max7219.h

@@ -6,8 +6,7 @@
 #include "esphome/components/spi/spi.h"
 #include "esphome/components/display/display.h"
 
-namespace esphome {
-namespace max7219 {
+namespace esphome::max7219 {
 
 class MAX7219Component;
 
@@ -17,6 +16,8 @@ class MAX7219Component : public PollingComponent,
                          public spi::SPIDevice<spi::BIT_ORDER_MSB_FIRST, spi::CLOCK_POLARITY_LOW,
                                                spi::CLOCK_PHASE_LEADING, spi::DATA_RATE_1MHZ> {
  public:
+  explicit MAX7219Component(uint8_t num_chips);
+
   void set_writer(max7219_writer_t &&writer);
 
   void setup() override;
@@ -30,7 +31,6 @@ class MAX7219Component : public PollingComponent,
   void display();
 
   void set_intensity(uint8_t intensity);
-  void set_num_chips(uint8_t num_chips);
   void set_reverse(bool reverse) { this->reverse_ = reverse; };
 
   /// Evaluate the printf-format and print the result at the given position.
@@ -56,10 +56,9 @@ class MAX7219Component : public PollingComponent,
   uint8_t intensity_{15};     // Intensity of the display from 0 to 15 (most)
   bool intensity_changed_{};  // True if we need to re-send the intensity
   uint8_t num_chips_{1};
-  uint8_t *buffer_;
+  uint8_t *buffer_{nullptr};
   bool reverse_{false};
   max7219_writer_t writer_{};
 };
 
-}  // namespace max7219
-}  // namespace esphome
+}  // namespace esphome::max7219

esphome/components/micro_wake_word/micro_wake_word.cpp

@@ -6,6 +6,7 @@
 #include "esphome/core/hal.h"
 #include "esphome/core/helpers.h"
 #include "esphome/core/log.h"
+#include "esphome/core/task_priorities.h"
 
 #include "esphome/components/audio/audio_transfer_buffer.h"
 
@@ -25,7 +26,6 @@ static const size_t DATA_TIMEOUT_MS = 50;
 static const uint32_t RING_BUFFER_DURATION_MS = 120;
 
 static const uint32_t INFERENCE_TASK_STACK_SIZE = 3072;
-static const UBaseType_t INFERENCE_TASK_PRIORITY = 3;
 
 enum EventGroupBits : uint32_t {
   COMMAND_STOP = (1 << 0),  // Signals the inference task should stop
@@ -305,8 +305,10 @@ void MicroWakeWord::loop() {
           return;
         }
 
+        // TASK_PRIORITY_INFERENCE: above main loop (TASK_PRIORITY_APPLICATION) but below
+        // protocol tasks (TASK_PRIORITY_PROTOCOL) - ML inference is background work
         xTaskCreate(MicroWakeWord::inference_task, "mww", INFERENCE_TASK_STACK_SIZE, (void *) this,
-                    INFERENCE_TASK_PRIORITY, &this->inference_task_handle_);
+                    TASK_PRIORITY_INFERENCE, &this->inference_task_handle_);
 
         if (this->inference_task_handle_ == nullptr) {
           FrontendFreeStateContents(&this->frontend_state_);  // Deallocate frontend state

esphome/components/mixer/speaker/mixer_speaker.cpp

@@ -5,6 +5,7 @@
 #include "esphome/core/hal.h"
 #include "esphome/core/helpers.h"
 #include "esphome/core/log.h"
+#include "esphome/core/task_priorities.h"
 
 #include <algorithm>
 #include <cstring>
@@ -12,8 +13,6 @@
 namespace esphome {
 namespace mixer_speaker {
 
-static const UBaseType_t MIXER_TASK_PRIORITY = 10;
-
 static const uint32_t TRANSFER_BUFFER_DURATION_MS = 50;
 static const uint32_t TASK_DELAY_MS = 25;
 
@@ -385,8 +384,10 @@ esp_err_t MixerSpeaker::start_task_() {
   }
 
   if (this->task_handle_ == nullptr) {
+    // TASK_PRIORITY_AUDIO_MIXER: below I2S tasks (TASK_PRIORITY_AUDIO_OUTPUT) but
+    // above protocol tasks - mixing is buffered but feeds real-time output
     this->task_handle_ = xTaskCreateStatic(audio_mixer_task, "mixer", TASK_STACK_SIZE, (void *) this,
-                                           MIXER_TASK_PRIORITY, this->task_stack_buffer_, &this->task_stack_);
+                                           TASK_PRIORITY_AUDIO_MIXER, this->task_stack_buffer_, &this->task_stack_);
   }
 
   if (this->task_handle_ == nullptr) {

esphome/components/mqtt/mqtt_backend_esp32.cpp

@@ -61,7 +61,10 @@ bool MQTTBackendESP32::initialize_() {
     // Create the task only after MQTT client is initialized successfully
     // Use larger stack size when TLS is enabled
     size_t stack_size = this->ca_certificate_.has_value() ? TASK_STACK_SIZE_TLS : TASK_STACK_SIZE;
-    xTaskCreate(esphome_mqtt_task, "esphome_mqtt", stack_size, (void *) this, TASK_PRIORITY, &this->task_handle_);
+    // TASK_PRIORITY_PROTOCOL: above main loop (TASK_PRIORITY_APPLICATION) but below
+    // audio tasks - MQTT needs responsive scheduling for message handling
+    xTaskCreate(esphome_mqtt_task, "esphome_mqtt", stack_size, (void *) this, TASK_PRIORITY_PROTOCOL,
+                &this->task_handle_);
     if (this->task_handle_ == nullptr) {
       ESP_LOGE(TAG, "Failed to create MQTT task");
       // Clean up MQTT client since we can't start the async task

esphome/components/mqtt/mqtt_backend_esp32.h

@@ -14,6 +14,7 @@
 #include "esphome/core/helpers.h"
 #include "esphome/core/lock_free_queue.h"
 #include "esphome/core/event_pool.h"
+#include "esphome/core/task_priorities.h"
 
 namespace esphome::mqtt {
 
@@ -117,8 +118,7 @@ class MQTTBackendESP32 final : public MQTTBackend {
   static const size_t MQTT_BUFFER_SIZE = 4096;
   static const size_t TASK_STACK_SIZE = 3072;
   static const size_t TASK_STACK_SIZE_TLS = 4096;  // Larger stack for TLS operations
-  static const ssize_t TASK_PRIORITY = 5;
-  static const uint8_t MQTT_QUEUE_LENGTH = 30;  // 30*12 bytes = 360
+  static const uint8_t MQTT_QUEUE_LENGTH = 30;     // 30*12 bytes = 360
 
   void set_keep_alive(uint16_t keep_alive) final { this->keep_alive_ = keep_alive; }
   void set_client_id(const char *client_id) final { this->client_id_ = client_id; }

esphome/components/openthread/openthread_esp.cpp

@@ -10,6 +10,7 @@
 #include "esp_task_wdt.h"
 #include "esphome/core/helpers.h"
 #include "esphome/core/log.h"
+#include "esphome/core/task_priorities.h"
 
 #include "esp_err.h"
 #include "esp_event.h"
@@ -39,12 +40,14 @@ void OpenThreadComponent::setup() {
   ESP_ERROR_CHECK(esp_netif_init());
   ESP_ERROR_CHECK(esp_vfs_eventfd_register(&eventfd_config));
 
+  // TASK_PRIORITY_PROTOCOL: same as USB host/MQTT - network protocol tasks need
+  // responsive scheduling but below audio tasks
   xTaskCreate(
       [](void *arg) {
         static_cast<OpenThreadComponent *>(arg)->ot_main();
         vTaskDelete(nullptr);
       },
-      "ot_main", 10240, this, 5, nullptr);
+      "ot_main", 10240, this, TASK_PRIORITY_PROTOCOL, nullptr);
 }
 
 static esp_netif_t *init_openthread_netif(const esp_openthread_platform_config_t *config) {

esphome/components/resampler/speaker/resampler_speaker.cpp

@@ -6,6 +6,7 @@
 
 #include "esphome/core/helpers.h"
 #include "esphome/core/log.h"
+#include "esphome/core/task_priorities.h"
 
 #include <algorithm>
 #include <cstring>
@@ -13,8 +14,6 @@
 namespace esphome {
 namespace resampler {
 
-static const UBaseType_t RESAMPLER_TASK_PRIORITY = 1;
-
 static const uint32_t TRANSFER_BUFFER_DURATION_MS = 50;
 
 static const uint32_t TASK_DELAY_MS = 20;
@@ -185,8 +184,10 @@ esp_err_t ResamplerSpeaker::start_task_() {
   }
 
   if (this->task_handle_ == nullptr) {
+    // TASK_PRIORITY_APPLICATION: same as main loop - resampling is buffered audio
+    // processing, not real-time I/O
     this->task_handle_ = xTaskCreateStatic(resample_task, "sample", TASK_STACK_SIZE, (void *) this,
-                                           RESAMPLER_TASK_PRIORITY, this->task_stack_buffer_, &this->task_stack_);
+                                           TASK_PRIORITY_APPLICATION, this->task_stack_buffer_, &this->task_stack_);
   }
 
   if (this->task_handle_ == nullptr) {

esphome/components/speaker/media_player/speaker_media_player.cpp

@@ -3,6 +3,7 @@
 #ifdef USE_ESP32
 
 #include "esphome/core/log.h"
+#include "esphome/core/task_priorities.h"
 
 #include "esphome/components/audio/audio.h"
 #ifdef USE_OTA
@@ -45,9 +46,6 @@ namespace speaker {
 
 static const uint32_t MEDIA_CONTROLS_QUEUE_LENGTH = 20;
 
-static const UBaseType_t MEDIA_PIPELINE_TASK_PRIORITY = 1;
-static const UBaseType_t ANNOUNCEMENT_PIPELINE_TASK_PRIORITY = 1;
-
 static const char *const TAG = "speaker_media_player";
 
 void SpeakerMediaPlayer::setup() {
@@ -70,9 +68,10 @@ void SpeakerMediaPlayer::setup() {
   ota::get_global_ota_callback()->add_global_state_listener(this);
 #endif
 
-  this->announcement_pipeline_ =
-      make_unique<AudioPipeline>(this->announcement_speaker_, this->buffer_size_, this->task_stack_in_psram_, "ann",
-                                 ANNOUNCEMENT_PIPELINE_TASK_PRIORITY);
+  // TASK_PRIORITY_APPLICATION: same as main loop - media pipelines handle buffered
+  // audio streaming, not real-time I/O, so they don't need elevated priority
+  this->announcement_pipeline_ = make_unique<AudioPipeline>(
+      this->announcement_speaker_, this->buffer_size_, this->task_stack_in_psram_, "ann", TASK_PRIORITY_APPLICATION);
 
   if (this->announcement_pipeline_ == nullptr) {
     ESP_LOGE(TAG, "Failed to create announcement pipeline");
@@ -81,7 +80,7 @@ void SpeakerMediaPlayer::setup() {
 
   if (!this->single_pipeline_()) {
     this->media_pipeline_ = make_unique<AudioPipeline>(this->media_speaker_, this->buffer_size_,
-                                                       this->task_stack_in_psram_, "med", MEDIA_PIPELINE_TASK_PRIORITY);
+                                                       this->task_stack_in_psram_, "med", TASK_PRIORITY_APPLICATION);
 
     if (this->media_pipeline_ == nullptr) {
       ESP_LOGE(TAG, "Failed to create media pipeline");

esphome/components/uart/uart_component_esp_idf.cpp

@@ -7,6 +7,7 @@
 #include "esphome/core/helpers.h"
 #include "esphome/core/log.h"
 #include "esphome/core/gpio.h"
+#include "esphome/core/task_priorities.h"
 #include "driver/gpio.h"
 #include "soc/gpio_num.h"
 #include "soc/uart_pins.h"
@@ -367,12 +368,13 @@ void IDFUARTComponent::check_logger_conflict() {}
 
 #ifdef USE_UART_WAKE_LOOP_ON_RX
 void IDFUARTComponent::start_rx_event_task_() {
-  // Create FreeRTOS task to monitor UART events
-  BaseType_t result = xTaskCreate(rx_event_task_func,    // Task function
-                                  "uart_rx_evt",         // Task name (max 16 chars)
-                                  2240,                  // Stack size in bytes (~2.2KB); increase if needed for logging
-                                  this,                  // Task parameter (this pointer)
-                                  tskIDLE_PRIORITY + 1,  // Priority (low, just above idle)
+  // TASK_PRIORITY_APPLICATION: same as main loop - UART RX monitoring is lightweight,
+  // just wakes main loop when data arrives
+  BaseType_t result = xTaskCreate(rx_event_task_func,  // Task function
+                                  "uart_rx_evt",       // Task name (max 16 chars)
+                                  2240,                // Stack size in bytes (~2.2KB)
+                                  this,                // Task parameter (this pointer)
+                                  TASK_PRIORITY_APPLICATION,
                                   &this->rx_event_task_handle_  // Task handle
   );
 

esphome/components/udp/__init__.py

@@ -12,8 +12,8 @@ from esphome.components.packet_transport import (
 )
 import esphome.config_validation as cv
 from esphome.const import CONF_DATA, CONF_ID, CONF_PORT, CONF_TRIGGER_ID
-from esphome.core import ID, Lambda
-from esphome.cpp_generator import ExpressionStatement, MockObj
+from esphome.core import ID
+from esphome.cpp_generator import literal
 
 CODEOWNERS = ["@clydebarrow"]
 DEPENDENCIES = ["network"]
@@ -24,6 +24,8 @@ udp_ns = cg.esphome_ns.namespace("udp")
 UDPComponent = udp_ns.class_("UDPComponent", cg.Component)
 UDPWriteAction = udp_ns.class_("UDPWriteAction", automation.Action)
 trigger_args = cg.std_vector.template(cg.uint8)
+trigger_argname = "data"
+trigger_argtype = [(trigger_args, trigger_argname)]
 
 CONF_ADDRESSES = "addresses"
 CONF_LISTEN_ADDRESS = "listen_address"
@@ -111,13 +113,14 @@ async def to_code(config):
     cg.add(var.set_addresses([str(addr) for addr in config[CONF_ADDRESSES]]))
     if on_receive := config.get(CONF_ON_RECEIVE):
         on_receive = on_receive[0]
-        trigger = cg.new_Pvariable(on_receive[CONF_TRIGGER_ID])
+        trigger_id = cg.new_Pvariable(on_receive[CONF_TRIGGER_ID])
         trigger = await automation.build_automation(
-            trigger, [(trigger_args, "data")], on_receive
+            trigger_id, trigger_argtype, on_receive
         )
-        trigger = Lambda(str(ExpressionStatement(trigger.trigger(MockObj("data")))))
-        trigger = await cg.process_lambda(trigger, [(trigger_args, "data")])
-        cg.add(var.add_listener(trigger))
+        trigger_lambda = await cg.process_lambda(
+            trigger.trigger(literal(trigger_argname)), trigger_argtype
+        )
+        cg.add(var.add_listener(trigger_lambda))
         cg.add(var.set_should_listen())
 
 

esphome/components/usb_cdc_acm/usb_cdc_acm_esp32.cpp

@@ -2,6 +2,7 @@
 #include "usb_cdc_acm.h"
 #include "esphome/core/application.h"
 #include "esphome/core/log.h"
+#include "esphome/core/task_priorities.h"
 
 #include <cstring>
 #include <sys/param.h>
@@ -155,13 +156,16 @@ void USBCDCACMInstance::setup() {
     return;
   }
 
-  // Use a larger stack size for (very) verbose logging
-  const size_t stack_size = esp_log_level_get(TAG) > ESP_LOG_DEBUG ? USB_TX_TASK_STACK_SIZE_VV : USB_TX_TASK_STACK_SIZE;
+  // Use a larger stack size for very verbose logging
+  constexpr size_t stack_size =
+      ESPHOME_LOG_LEVEL >= ESPHOME_LOG_LEVEL_VERY_VERBOSE ? USB_TX_TASK_STACK_SIZE_VV : USB_TX_TASK_STACK_SIZE;
 
   // Create a simple, unique task name per interface
   char task_name[] = "usb_tx_0";
   task_name[sizeof(task_name) - 1] = format_hex_char(static_cast<char>(this->itf_));
-  xTaskCreate(usb_tx_task_fn, task_name, stack_size, this, 4, &this->usb_tx_task_handle_);
+  // TASK_PRIORITY_USB_SERIAL: above main loop (TASK_PRIORITY_APPLICATION) and
+  // wake word (TASK_PRIORITY_INFERENCE), below protocol tasks (TASK_PRIORITY_PROTOCOL)
+  xTaskCreate(usb_tx_task_fn, task_name, stack_size, this, TASK_PRIORITY_USB_SERIAL, &this->usb_tx_task_handle_);
 
   if (this->usb_tx_task_handle_ == nullptr) {
     ESP_LOGE(TAG, "Failed to create USB TX task for itf %d", this->itf_);

esphome/components/usb_host/usb_host.h

@@ -4,6 +4,7 @@
 #if defined(USE_ESP32_VARIANT_ESP32P4) || defined(USE_ESP32_VARIANT_ESP32S2) || defined(USE_ESP32_VARIANT_ESP32S3)
 #include "esphome/core/defines.h"
 #include "esphome/core/component.h"
+#include "esphome/core/task_priorities.h"
 #include <vector>
 #include "usb/usb_host.h"
 #include <freertos/FreeRTOS.h>
@@ -69,7 +70,6 @@ static constexpr trq_bitmask_t ALL_REQUESTS_IN_USE = MAX_REQUESTS == 32 ? ~0 : (
 
 static constexpr size_t USB_EVENT_QUEUE_SIZE = 32;   // Size of event queue between USB task and main loop
 static constexpr size_t USB_TASK_STACK_SIZE = 4096;  // Stack size for USB task (same as ESP-IDF USB examples)
-static constexpr UBaseType_t USB_TASK_PRIORITY = 5;  // Higher priority than main loop (tskIDLE_PRIORITY + 5)
 
 // used to report a transfer status
 struct TransferStatus {

esphome/components/usb_host/usb_host_client.cpp

@@ -215,11 +215,12 @@ void USBClient::setup() {
   }
 
   // Create and start USB task
+  // TASK_PRIORITY_PROTOCOL: above main loop (TASK_PRIORITY_APPLICATION) but below
+  // audio tasks - USB host needs responsive scheduling for device communication
   xTaskCreate(usb_task_fn, "usb_task",
               USB_TASK_STACK_SIZE,  // Stack size
               this,                 // Task parameter
-              USB_TASK_PRIORITY,    // Priority (higher than main loop)
-              &this->usb_task_handle_);
+              TASK_PRIORITY_PROTOCOL, &this->usb_task_handle_);
 
   if (this->usb_task_handle_ == nullptr) {
     ESP_LOGE(TAG, "Failed to create USB task");

esphome/core/__init__.py

@@ -278,9 +278,13 @@ LAMBDA_PROG = re.compile(r"\bid\(\s*([a-zA-Z_][a-zA-Z0-9_]*)\s*\)(\.?)")
 
 class Lambda:
     def __init__(self, value):
+        from esphome.cpp_generator import Expression, statement
+
         # pylint: disable=protected-access
         if isinstance(value, Lambda):
             self._value = value._value
+        elif isinstance(value, Expression):
+            self._value = str(statement(value))
         else:
             self._value = value
         self._parts = None

esphome/core/task_priorities.h

@@ -0,0 +1,61 @@
+#pragma once
+
+#ifdef USE_ESP32
+
+#include <freertos/FreeRTOS.h>
+
+namespace esphome {
+
+/// @brief FreeRTOS task priority definitions for ESPHome
+///
+/// All priorities use relative values based on configMAX_PRIORITIES so they
+/// scale automatically if CONFIG_FREERTOS_MAX_PRIORITIES changes.
+///
+/// Priority hierarchy (with CONFIG_FREERTOS_MAX_PRIORITIES = 16):
+///
+///   14: Audio capture (I2S microphone) - highest, real-time audio input
+///   10: Audio output (I2S speaker) - real-time audio output
+///    8: Network stack (LWIP TCP/IP) - set via CONFIG_LWIP_TCPIP_TASK_PRIO
+///    6: Audio mixing - buffered audio processing
+///    5: Protocol tasks (MQTT, USB host, OpenThread) - communication
+///    4: USB serial TX - serial communication
+///    3: ML inference (wake word) - background ML processing
+///    1: Application (main loop, media pipelines, camera, UART RX) - baseline
+///    0: Idle task (FreeRTOS system)
+///
+/// Guidelines:
+/// - Real-time audio I/O tasks need highest priorities to prevent glitches
+/// - Network/protocol tasks should be above application but below audio
+/// - Background processing (ML, media decoding) can run at low priority
+
+/// Audio capture task priority (I2S microphone)
+/// Highest application priority - audio input cannot tolerate delays
+static constexpr UBaseType_t TASK_PRIORITY_AUDIO_CAPTURE = configMAX_PRIORITIES - 2;
+
+/// Audio output task priority (I2S speaker)
+/// High priority - audio output needs consistent timing
+static constexpr UBaseType_t TASK_PRIORITY_AUDIO_OUTPUT = configMAX_PRIORITIES - 6;
+
+/// Audio mixer task priority
+/// Medium-high - mixing is buffered but feeds real-time output
+static constexpr UBaseType_t TASK_PRIORITY_AUDIO_MIXER = configMAX_PRIORITIES - 10;
+
+/// Protocol/communication task priority (MQTT, USB host, OpenThread)
+/// Above application tasks for responsive network handling
+static constexpr UBaseType_t TASK_PRIORITY_PROTOCOL = configMAX_PRIORITIES - 11;
+
+/// USB serial TX task priority
+/// Slightly below protocol tasks
+static constexpr UBaseType_t TASK_PRIORITY_USB_SERIAL = configMAX_PRIORITIES - 12;
+
+/// ML inference task priority (wake word detection)
+/// Background processing - can yield to communication tasks
+static constexpr UBaseType_t TASK_PRIORITY_INFERENCE = configMAX_PRIORITIES - 13;
+
+/// Application task priority (main loop, media pipelines, camera, etc.)
+/// Baseline priority - just above idle task
+static constexpr UBaseType_t TASK_PRIORITY_APPLICATION = tskIDLE_PRIORITY + 1;
+
+}  // namespace esphome
+
+#endif  // USE_ESP32

esphome/cpp_generator.py

@@ -462,6 +462,16 @@ def statement(expression: Expression | Statement) -> Statement:
     return ExpressionStatement(expression)
 
 
+def literal(name: str) -> "MockObj":
+    """Create a literal name that will appear in the generated code
+    not surrounded by quotes.
+
+    :param name: The name of the literal.
+    :return: The literal as a MockObj.
+    """
+    return MockObj(name, "")
+
+
 def variable(
     id_: ID, rhs: SafeExpType, type_: "MockObj" = None, register=True
 ) -> "MockObj":
@@ -665,7 +675,7 @@ async def get_variable_with_full_id(id_: ID) -> tuple[ID, "MockObj"]:
 
 
 async def process_lambda(
-    value: Lambda,
+    value: Lambda | Expression,
     parameters: TemplateArgsType,
     capture: str = "",
     return_type: SafeExpType = None,
@@ -689,6 +699,14 @@ async def process_lambda(
 
     if value is None:
         return None
+    # Inadvertently passing a malformed parameters value will lead to the build process mysteriously hanging at the
+    # "Generating C++ source..." stage, so check here to save the developer's hair.
+    assert isinstance(parameters, list) and all(
+        isinstance(p, tuple) and len(p) == 2 for p in parameters
+    )
+    if isinstance(value, Expression):
+        value = Lambda(value)
+
     parts = value.parts[:]
     for i, id in enumerate(value.requires_ids):
         full_id, var = await get_variable_with_full_id(id)

tests/components/dlms_meter/common-generic.yaml

@@ -0,0 +1,11 @@
+dlms_meter:
+  decryption_key: "36C66639E48A8CA4D6BC8B282A793BBB"   # change this to your decryption key!
+
+sensor:
+  - platform: dlms_meter
+    reactive_energy_plus:
+      name: "Reactive energy taken from grid"
+    reactive_energy_minus:
+      name: "Reactive energy put into grid"
+
+<<: !include common.yaml

tests/components/dlms_meter/common-netznoe.yaml

@@ -0,0 +1,17 @@
+dlms_meter:
+  decryption_key: "36C66639E48A8CA4D6BC8B282A793BBB"  # change this to your decryption key!
+  provider: netznoe                                   # (optional) key - only set if using evn
+
+sensor:
+  - platform: dlms_meter
+    # EVN
+    power_factor:
+      name: "Power Factor"
+
+text_sensor:
+  - platform: dlms_meter
+    # EVN
+    meternumber:
+      name: "meterNumber"
+
+<<: !include common.yaml

tests/components/dlms_meter/common.yaml

@@ -0,0 +1,27 @@
+sensor:
+  - platform: dlms_meter
+    voltage_l1:
+      name: "Voltage L1"
+    voltage_l2:
+      name: "Voltage L2"
+    voltage_l3:
+      name: "Voltage L3"
+    current_l1:
+      name: "Current L1"
+    current_l2:
+      name: "Current L2"
+    current_l3:
+      name: "Current L3"
+    active_power_plus:
+      name: "Active power taken from grid"
+    active_power_minus:
+      name: "Active power put into grid"
+    active_energy_plus:
+      name: "Active energy taken from grid"
+    active_energy_minus:
+      name: "Active energy put into grid"
+
+text_sensor:
+  - platform: dlms_meter
+    timestamp:
+      name: "timestamp"

tests/components/dlms_meter/test.esp32-ard.yaml

@@ -0,0 +1,4 @@
+packages:
+  uart: !include ../../test_build_components/common/uart_2400/esp32-ard.yaml
+
+<<: !include common-generic.yaml

tests/components/dlms_meter/test.esp32-idf.yaml

@@ -0,0 +1,4 @@
+packages:
+  uart: !include ../../test_build_components/common/uart_2400/esp32-idf.yaml
+
+<<: !include common-netznoe.yaml

tests/components/dlms_meter/test.esp8266-ard.yaml

@@ -0,0 +1,4 @@
+packages:
+  uart: !include ../../test_build_components/common/uart_2400/esp8266-ard.yaml
+
+<<: !include common-generic.yaml

tests/test_build_components/common/uart_2400/esp32-ard.yaml

@@ -0,0 +1,11 @@
+# Common UART configuration for ESP32 Arduino tests - 2400 baud
+
+substitutions:
+  tx_pin: GPIO17
+  rx_pin: GPIO16
+
+uart:
+  - id: uart_bus
+    tx_pin: ${tx_pin}
+    rx_pin: ${rx_pin}
+    baud_rate: 2400

tests/test_build_components/common/uart_2400/esp32-idf.yaml

@@ -0,0 +1,11 @@
+# Common UART configuration for ESP32 IDF tests - 2400 baud
+
+substitutions:
+  tx_pin: GPIO17
+  rx_pin: GPIO16
+
+uart:
+  - id: uart_bus
+    tx_pin: ${tx_pin}
+    rx_pin: ${rx_pin}
+    baud_rate: 2400

tests/test_build_components/common/uart_2400/esp8266-ard.yaml

@@ -0,0 +1,11 @@
+# Common UART configuration for ESP8266 Arduino tests - 2400 baud
+
+substitutions:
+  tx_pin: GPIO4
+  rx_pin: GPIO5
+
+uart:
+  - id: uart_bus
+    tx_pin: ${tx_pin}
+    rx_pin: ${rx_pin}
+    baud_rate: 2400

tests/unit_tests/test_cpp_generator.py

@@ -347,3 +347,280 @@ class TestMockObj:
         assert isinstance(actual, cg.MockObj)
         assert actual.base == "foo.eek"
         assert actual.op == "."
+
+
+class TestStatementFunction:
+    """Tests for the statement() function."""
+
+    def test_statement__expression_converted_to_statement(self):
+        """Test that expressions are converted to ExpressionStatement."""
+        expr = cg.RawExpression("foo()")
+        result = cg.statement(expr)
+
+        assert isinstance(result, cg.ExpressionStatement)
+        assert str(result) == "foo();"
+
+    def test_statement__statement_unchanged(self):
+        """Test that statements are returned unchanged."""
+        stmt = cg.RawStatement("foo()")
+        result = cg.statement(stmt)
+
+        assert result is stmt
+        assert str(result) == "foo()"
+
+    def test_statement__expression_statement_unchanged(self):
+        """Test that ExpressionStatement is returned unchanged."""
+        stmt = cg.ExpressionStatement(42)
+        result = cg.statement(stmt)
+
+        assert result is stmt
+        assert str(result) == "42;"
+
+    def test_statement__line_comment_unchanged(self):
+        """Test that LineComment is returned unchanged."""
+        stmt = cg.LineComment("This is a comment")
+        result = cg.statement(stmt)
+
+        assert result is stmt
+        assert str(result) == "// This is a comment"
+
+
+class TestLiteralFunction:
+    """Tests for the literal() function."""
+
+    def test_literal__creates_mockobj(self):
+        """Test that literal() creates a MockObj."""
+        result = cg.literal("MY_CONSTANT")
+
+        assert isinstance(result, cg.MockObj)
+        assert result.base == "MY_CONSTANT"
+        assert result.op == ""
+
+    def test_literal__string_representation(self):
+        """Test that literal names appear unquoted in generated code."""
+        result = cg.literal("nullptr")
+
+        assert str(result) == "nullptr"
+
+    def test_literal__can_be_used_in_expressions(self):
+        """Test that literals can be used as part of larger expressions."""
+        null_lit = cg.literal("nullptr")
+        expr = cg.CallExpression(cg.RawExpression("my_func"), null_lit)
+
+        assert str(expr) == "my_func(nullptr)"
+
+    def test_literal__common_cpp_literals(self):
+        """Test common C++ literal values."""
+        test_cases = [
+            ("nullptr", "nullptr"),
+            ("true", "true"),
+            ("false", "false"),
+            ("NULL", "NULL"),
+            ("NAN", "NAN"),
+        ]
+
+        for name, expected in test_cases:
+            result = cg.literal(name)
+            assert str(result) == expected
+
+
+class TestLambdaConstructor:
+    """Tests for the Lambda class constructor in core/__init__.py."""
+
+    def test_lambda__from_string(self):
+        """Test Lambda constructor with string argument."""
+        from esphome.core import Lambda
+
+        lambda_obj = Lambda("return x + 1;")
+
+        assert lambda_obj.value == "return x + 1;"
+        assert str(lambda_obj) == "return x + 1;"
+
+    def test_lambda__from_expression(self):
+        """Test Lambda constructor with Expression argument."""
+        from esphome.core import Lambda
+
+        expr = cg.RawExpression("x + 1")
+        lambda_obj = Lambda(expr)
+
+        # Expression should be converted to statement (with semicolon)
+        assert lambda_obj.value == "x + 1;"
+
+    def test_lambda__from_lambda(self):
+        """Test Lambda constructor with another Lambda argument."""
+        from esphome.core import Lambda
+
+        original = Lambda("return x + 1;")
+        copy = Lambda(original)
+
+        assert copy.value == original.value
+        assert copy.value == "return x + 1;"
+
+    def test_lambda__parts_parsing(self):
+        """Test that Lambda correctly parses parts with id() references."""
+        from esphome.core import Lambda
+
+        lambda_obj = Lambda("return id(my_sensor).state;")
+        parts = lambda_obj.parts
+
+        # Parts should be split by LAMBDA_PROG regex: text, id, op, text
+        assert len(parts) == 4
+        assert parts[0] == "return "
+        assert parts[1] == "my_sensor"
+        assert parts[2] == "."
+        assert parts[3] == "state;"
+
+    def test_lambda__requires_ids(self):
+        """Test that Lambda correctly extracts required IDs."""
+        from esphome.core import ID, Lambda
+
+        lambda_obj = Lambda("return id(sensor1).state + id(sensor2).value;")
+        ids = lambda_obj.requires_ids
+
+        assert len(ids) == 2
+        assert all(isinstance(id_obj, ID) for id_obj in ids)
+        assert ids[0].id == "sensor1"
+        assert ids[1].id == "sensor2"
+
+    def test_lambda__no_ids(self):
+        """Test Lambda with no id() references."""
+        from esphome.core import Lambda
+
+        lambda_obj = Lambda("return 42;")
+        ids = lambda_obj.requires_ids
+
+        assert len(ids) == 0
+
+    def test_lambda__comment_removal(self):
+        """Test that comments are removed when parsing parts."""
+        from esphome.core import Lambda
+
+        lambda_obj = Lambda("return id(sensor).state; // Get sensor state")
+        parts = lambda_obj.parts
+
+        # Comment should be replaced with space, not affect parsing
+        assert "my_sensor" not in str(parts)
+
+    def test_lambda__multiline_string(self):
+        """Test Lambda with multiline string."""
+        from esphome.core import Lambda
+
+        code = """if (id(sensor).state > 0) {
+  return true;
+}
+return false;"""
+        lambda_obj = Lambda(code)
+
+        assert lambda_obj.value == code
+        assert "sensor" in [id_obj.id for id_obj in lambda_obj.requires_ids]
+
+
+@pytest.mark.asyncio
+class TestProcessLambda:
+    """Tests for the process_lambda() async function."""
+
+    async def test_process_lambda__none_value(self):
+        """Test that None returns None."""
+        result = await cg.process_lambda(None, [])
+
+        assert result is None
+
+    async def test_process_lambda__with_expression(self):
+        """Test process_lambda with Expression argument."""
+
+        expr = cg.RawExpression("return x + 1")
+        result = await cg.process_lambda(expr, [(int, "x")])
+
+        assert isinstance(result, cg.LambdaExpression)
+        assert "x + 1" in str(result)
+
+    async def test_process_lambda__simple_lambda_no_ids(self):
+        """Test process_lambda with simple Lambda without id() references."""
+        from esphome.core import Lambda
+
+        lambda_obj = Lambda("return x + 1;")
+        result = await cg.process_lambda(lambda_obj, [(int, "x")])
+
+        assert isinstance(result, cg.LambdaExpression)
+        # Should have parameter
+        lambda_str = str(result)
+        assert "int32_t x" in lambda_str
+        assert "return x + 1;" in lambda_str
+
+    async def test_process_lambda__with_return_type(self):
+        """Test process_lambda with return type specified."""
+        from esphome.core import Lambda
+
+        lambda_obj = Lambda("return x > 0;")
+        result = await cg.process_lambda(lambda_obj, [(int, "x")], return_type=bool)
+
+        assert isinstance(result, cg.LambdaExpression)
+        lambda_str = str(result)
+        assert "-> bool" in lambda_str
+
+    async def test_process_lambda__with_capture(self):
+        """Test process_lambda with capture specified."""
+        from esphome.core import Lambda
+
+        lambda_obj = Lambda("return captured + x;")
+        result = await cg.process_lambda(lambda_obj, [(int, "x")], capture="captured")
+
+        assert isinstance(result, cg.LambdaExpression)
+        lambda_str = str(result)
+        assert "[captured]" in lambda_str
+
+    async def test_process_lambda__empty_capture(self):
+        """Test process_lambda with empty capture (stateless lambda)."""
+        from esphome.core import Lambda
+
+        lambda_obj = Lambda("return x + 1;")
+        result = await cg.process_lambda(lambda_obj, [(int, "x")], capture="")
+
+        assert isinstance(result, cg.LambdaExpression)
+        lambda_str = str(result)
+        assert "[]" in lambda_str
+
+    async def test_process_lambda__no_parameters(self):
+        """Test process_lambda with no parameters."""
+        from esphome.core import Lambda
+
+        lambda_obj = Lambda("return 42;")
+        result = await cg.process_lambda(lambda_obj, [])
+
+        assert isinstance(result, cg.LambdaExpression)
+        lambda_str = str(result)
+        # Should have empty parameter list
+        assert "()" in lambda_str
+
+    async def test_process_lambda__multiple_parameters(self):
+        """Test process_lambda with multiple parameters."""
+        from esphome.core import Lambda
+
+        lambda_obj = Lambda("return x + y + z;")
+        result = await cg.process_lambda(
+            lambda_obj, [(int, "x"), (float, "y"), (bool, "z")]
+        )
+
+        assert isinstance(result, cg.LambdaExpression)
+        lambda_str = str(result)
+        assert "int32_t x" in lambda_str
+        assert "float y" in lambda_str
+        assert "bool z" in lambda_str
+
+    async def test_process_lambda__parameter_validation(self):
+        """Test that malformed parameters raise assertion error."""
+        from esphome.core import Lambda
+
+        lambda_obj = Lambda("return x;")
+
+        # Test invalid parameter format (not list of tuples)
+        with pytest.raises(AssertionError):
+            await cg.process_lambda(lambda_obj, "invalid")
+
+        # Test invalid tuple format (not 2-element tuples)
+        with pytest.raises(AssertionError):
+            await cg.process_lambda(lambda_obj, [(int, "x", "extra")])
+
+        # Test invalid tuple format (single element)
+        with pytest.raises(AssertionError):
+            await cg.process_lambda(lambda_obj, [(int,)])