/** * @file DShotRMT.h * @brief Optimized DShot signal generation using ESP32 RMT with bidirectional support * @author Wastl Kraus * @date 2025-09-18 * @license MIT */ #pragma once #include #include #include #include #include #include // DShot Protocol Constants & Types static constexpr auto DSHOT_THROTTLE_FAILSAFE = 0; static constexpr auto DSHOT_THROTTLE_MIN = 48; static constexpr auto DSHOT_THROTTLE_MAX = 2047; static constexpr auto DSHOT_BITS_PER_FRAME = 16; static constexpr auto DEFAULT_MOTOR_MAGNET_COUNT = 14; // Custom status codes static constexpr auto DSHOT_OK = 0; static constexpr auto DSHOT_ERROR = 1; // DShot Modes typedef enum dshot_mode { DSHOT_OFF, DSHOT150, DSHOT300, DSHOT600, DSHOT1200 } dshot_mode_t; // DShot Packet Structure typedef struct dshot_packet { uint16_t throttle_value : 11; bool telemetric_request : 1; uint16_t checksum : 4; } dshot_packet_t; // DShot Timing Configuration typedef struct dshot_timing { double bit_length_us; double t1h_lenght_us; } dshot_timing_us_t; // RMT Timing Configuration typedef struct rmt_ticks { uint16_t bit_length_ticks; uint16_t t1h_ticks; uint16_t t1l_ticks; uint16_t t0h_ticks; uint16_t t0l_ticks; } rmt_ticks_t; // Unified DShot Result Structure typedef struct dshot_result { bool success; const char *msg; uint16_t erpm; uint16_t motor_rpm; } dshot_result_t; // Command Type Alias typedef dshotCommands_e dshot_commands_t; // Helper Functions void printDShotResult(dshot_result_t &result, Stream &output = Serial); // // DShotRMT Main Class class DShotRMT { public: // Constructors & Destructor explicit DShotRMT(gpio_num_t gpio = GPIO_NUM_16, dshot_mode_t mode = DSHOT300, bool is_bidirectional = false); DShotRMT(uint16_t pin_nr, dshot_mode_t mode, bool is_bidirectional); ~DShotRMT(); // Public Core Functions dshot_result_t begin(); dshot_result_t sendThrottle(uint16_t throttle); dshot_result_t sendCommand(uint16_t command); dshot_result_t sendCommand(dshot_commands_t dshot_command, uint16_t repeat_count = DEFAULT_CMD_REPEAT_COUNT, uint16_t delay_us = DEFAULT_CMD_DELAY_US); dshot_result_t getTelemetry(uint16_t magnet_count = DEFAULT_MOTOR_MAGNET_COUNT); dshot_result_t getESCInfo(); dshot_result_t setMotorSpinDirection(bool reversed); dshot_result_t saveESCSettings(); // Public Utility & Info Functions void printDShotInfo(Stream &output = Serial) const; void printCpuInfo(Stream &output = Serial) const; // Deprecated Methods [[deprecated("Use sendThrottle() instead")]] bool setThrottle(uint16_t throttle) { auto result = sendThrottle(throttle); return result.success; } [[deprecated("Use sendCommand() instead")]] bool sendDShotCommand(uint16_t command) { auto result = sendCommand(command); return result.success; } [[deprecated("Use getTelemetry() instead")]] uint32_t getMotorRPM(uint8_t magnet_count) { auto result = getTelemetry(magnet_count); return result.motor_rpm; } private: // Configuration Constants static constexpr auto const DSHOT_NULL_PACKET = 0b0000000000000000; static constexpr auto const DSHOT_FULL_PACKET = 0b1111111111111111; static constexpr auto const DSHOT_CRC_MASK = 0b0000000000001111; static constexpr auto const DSHOT_CLOCK_SRC_DEFAULT = RMT_CLK_SRC_DEFAULT; static constexpr auto const DSHOT_RMT_RESOLUTION = 8 * 1000 * 1000; // 8 MHz resolution static constexpr auto const RMT_TICKS_PER_US = DSHOT_RMT_RESOLUTION / (1 * 1000 * 1000); // RMT Ticks per microsecond static constexpr auto const DSHOT_RX_TIMEOUT_MS = 2; static constexpr auto const DSHOT_PADDING_US = 20; // Add to pause between frames for compatibility static constexpr auto const RMT_BUFFER_SYMBOLS = 128; static constexpr auto const RMT_QUEUE_DEPTH = 1; static constexpr auto const GCR_BITS_PER_FRAME = 21; // Number of GCR bits in a DShot answer frame static constexpr auto const POLE_PAIRS_MIN = 1; static constexpr auto const MAGNETS_PER_POLE_PAIR = 2; static constexpr auto const NO_DSHOT_TELEMETRY = 0; static constexpr auto const DSHOT_PULSE_MIN = 800; // 0.8us minimum pulse static constexpr auto const DSHOT_PULSE_MAX = 8000; // 8.0us maximum pulse static constexpr auto const DSHOT_TELEMETRY_INVALID = DSHOT_THROTTLE_MAX; // Error Messages static constexpr char const *NONE = ""; static constexpr char const *UNKNOWN_ERROR = "Unknown Error!"; static constexpr char const *INIT_SUCCESS = "SignalGeneratorRMT initialized successfully"; static constexpr char const *INIT_FAILED = "SignalGeneratorRMT init failed!"; static constexpr char const *TX_INIT_SUCCESS = "TX RMT channel initialized successfully"; static constexpr char const *TX_INIT_FAILED = "TX RMT channel init failed!"; static constexpr char const *RX_INIT_SUCCESS = "RX RMT channel initialized successfully"; static constexpr char const *RX_INIT_FAILED = "RX RMT channel init failed!"; static constexpr char const *ENCODER_INIT_SUCCESS = "RMT encoder initialized successfully"; static constexpr char const *ENCODER_INIT_FAILED = "RMT encoder init failed!"; static constexpr char const *ENCODING_SUCCESS = "Packet encoded successfully"; static constexpr char const *TRANSMISSION_SUCCESS = "Transmission successfully"; static constexpr char const *TRANSMISSION_FAILED = "Transmission failed!"; static constexpr char const *RECEIVER_FAILED = "RMT receiver failed!"; static constexpr char const *THROTTLE_NOT_IN_RANGE = "Throttle not in range! (48 - 2047)"; static constexpr char const *COMMAND_NOT_VALID = "Command not valid! (0 - 47)"; static constexpr char const *BIDIR_NOT_ENABLED = "Bidirectional DShot not enabled!"; static constexpr char const *TELEMETRY_SUCCESS = "Valid Telemetric Frame received!"; static constexpr char const *TELEMETRY_FAILED = "No valid Telemetric Frame received!"; static constexpr char const *INVALID_MAGNET_COUNT = "Invalid motor magnet count!"; static constexpr char const *TIMING_CORRECTION = "Timing correction!"; static constexpr char const *CALLBACK_REGISTERING_FAILED = "RMT RX Callback registering failed!"; static constexpr char const *INVALID_COMMAND = "Invalid command!"; static constexpr char const *COMMAND_SUCCESS = "DShot command sent successfully"; // --- UTILITY METHODS --- bool _isValidCommand(dshot_commands_t command); dshot_result_t _executeCommand(dshot_commands_t command); // Core Configuration Variables gpio_num_t _gpio; dshot_mode_t _mode; bool _is_bidirectional; const dshot_timing_us_t &_dshot_timing; uint64_t _frame_timer_us; // Timing & Packet Variables rmt_ticks_t _rmt_ticks; uint16_t _last_throttle; uint64_t _last_transmission_time_us; uint64_t _last_command_timestamp; uint16_t _parsed_packet; dshot_packet_t _packet; uint8_t _bitPositions[DSHOT_BITS_PER_FRAME]; uint16_t _level0; // Signal level for the first part of a pulse (always HIGH for DShot) uint16_t _level1; // Signal level for the second part of a pulse (always LOW for DShot) // RMT Hardware Handles rmt_channel_handle_t _rmt_tx_channel; rmt_channel_handle_t _rmt_rx_channel; rmt_encoder_handle_t _dshot_encoder; // RMT Configuration Structures rmt_tx_channel_config_t _tx_channel_config; rmt_rx_channel_config_t _rx_channel_config; rmt_transmit_config_t _rmt_tx_config; rmt_receive_config_t _rmt_rx_config; // Bidirectional / Telemetry Variables rmt_rx_event_callbacks_t _rx_event_callbacks; std::atomic _last_erpm_atomic; std::atomic _telemetry_ready_flag_atomic; // Private Initialization Functions dshot_result_t _initTXChannel(); dshot_result_t _initRXChannel(); dshot_result_t _initDShotEncoder(); // Private Packet Management Functions dshot_packet_t _buildDShotPacket(const uint16_t &value); uint16_t _parseDShotPacket(const dshot_packet_t &packet); uint16_t _calculateCRC(const uint16_t &data); void _preCalculateRMTTicks(); void _preCalculateBitPositions(); // Private Frame Processing Functions dshot_result_t _sendDShotFrame(const dshot_packet_t &packet); dshot_result_t _encodeDShotFrame(const dshot_packet_t &packet, rmt_symbol_word_t *symbols); uint16_t _decodeDShotFrame(const rmt_symbol_word_t *symbols); // Private Timing Control Functions bool _timer_signal(); bool _timer_reset(); // Static Callback Functions static bool _on_rx_done(rmt_channel_handle_t rmt_rx_channel, const rmt_rx_done_event_data_t *edata, void *user_data); // Command Constants static constexpr auto DEFAULT_CMD_DELAY_US = 10; static constexpr auto DEFAULT_CMD_REPEAT_COUNT = 1; static constexpr auto SETTINGS_COMMAND_REPEATS = 10; // Settings commands need 10 repeats static constexpr auto SETTINGS_COMMAND_DELAY_US = 5; };