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

esphome/core/task_priorities.h

@@ -0,0 +1,57 @@
+#pragma once
+
+#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