/** * @file DShotRMT.h * @brief DShot signal generation using ESP32 RMT with bidirectional support * @author Wastl Kraus * @date 2025-06-11 * @license MIT */ #pragma once #include #include #include #include #include // DShot Protocol Constants constexpr auto DSHOT_THROTTLE_FAILSAFE = 0; constexpr auto DSHOT_THROTTLE_MIN = 48; constexpr auto DSHOT_THROTTLE_MAX = 2047; constexpr auto DSHOT_BITS_PER_FRAME = 16; constexpr auto DSHOT_SWITCH_TIME = 30; // Time in us between TX and RX constexpr auto DSHOT_NULL_PACKET = 0b0000000000000000; constexpr auto DSHOT_RX_TIMEOUT_MS = 2; // RMT Configuration Constants constexpr auto DSHOT_CLOCK_SRC_DEFAULT = RMT_CLK_SRC_DEFAULT; constexpr auto DSHOT_RMT_RESOLUTION = 10 * 1000 * 1000; // 10 MHz resolution constexpr auto RMT_BUFFER_SIZE = DSHOT_BITS_PER_FRAME; constexpr auto GCR_BITS_PER_FRAME = 21; // Number of GCR bits in a DShot answer frame (1 start + 16 data + 4 CRC) constexpr auto RMT_BUFFER_SYMBOLS = 64; constexpr auto RMT_QUEUE_DEPTH = 1; // Smallest pulse for DShot1200 is 2us. Largest for DShot150 is 40us. // The range is set from 3us (3000ns) to 60us (60000ns) to be safe across all modes. constexpr uint32_t DSHOT_PULSE_MIN = 3000; constexpr uint32_t DSHOT_PULSE_MAX = 60000; // DShot Mode Enumeration typedef enum { DSHOT_OFF, DSHOT150, DSHOT300, DSHOT600, DSHOT1200 } dshot_mode_t; // DShot Packet Structure typedef struct { uint16_t throttle_value : 11; bool telemetric_request : 1; uint16_t checksum : 4; } dshot_packet_t; // DShot Timing Configuration Structure typedef struct { uint32_t frame_length_us; uint16_t ticks_per_bit; uint16_t ticks_one_high; uint16_t ticks_one_low; uint16_t ticks_zero_high; uint16_t ticks_zero_low; } dshot_timing_t; // Command execution result structure typedef struct { bool success; const char *error_message; } dshot_result_t; // DShot telemetry result structure typedef struct { bool success; uint16_t erpm; uint32_t motor_rpm; const char *error_message; } dshot_telemetry_result_t; // Naming convention typedef dshotCommands_e dshot_commands_t; // class DShotRMT { public: // Constructor with GPIO enum explicit DShotRMT(gpio_num_t gpio = GPIO_NUM_16, dshot_mode_t mode = DSHOT300, bool is_bidirectional = false); // Constructor with pin number DShotRMT(uint16_t pin_nr, dshot_mode_t mode, bool is_bidirectional); // Destructor for "better" code ~DShotRMT(); // Initialize the RMT module and DShot config dshot_result_t begin(); // Send throttle value (48-2047) dshot_result_t sendThrottle(uint16_t throttle); // Send DShot command (0-47) dshot_result_t sendCommand(uint16_t command); // Get telemetry data (bidirectional mode only) dshot_telemetry_result_t getTelemetry(uint8_t magnet_count = 14); // Get eRPM only (bidirectional mode only) uint16_t getERPM(); // --- GETTERS --- gpio_num_t getGPIO() const { return _gpio; } uint16_t getDShotPacket() const { return _parsed_packet; } bool is_bidirectional() const { return _is_bidirectional; } dshot_mode_t getMode() const { return _mode; } // Get execution statistics uint32_t getTotalTransmissions() const { return _total_transmissions; } uint32_t getFailedTransmissions() const { return _failed_transmissions; } // --- INFO --- 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.success; } private: // --- CONFIG --- gpio_num_t _gpio; dshot_mode_t _mode; bool _is_bidirectional; uint32_t _frame_timer_us; const dshot_timing_t &_timing_config; // --- TIMING & STATE VARIABLES --- uint64_t _last_transmission_time; uint16_t _last_erpm; uint16_t _parsed_packet; dshot_packet_t _packet; // --- STATISTICS --- uint32_t _total_transmissions; uint32_t _failed_transmissions; // --- RMT HARDWARE HANDLES --- rmt_channel_handle_t _rmt_tx_channel; rmt_channel_handle_t _rmt_rx_channel; rmt_encoder_handle_t _dshot_encoder; // --- RMT CONFIG STRUCTURES --- rmt_tx_channel_config_t _tx_channel_config; rmt_rx_channel_config_t _rx_channel_config; rmt_transmit_config_t _transmit_config; rmt_receive_config_t _receive_config; // --- INITS --- bool _initTXChannel(); bool _initRXChannel(); bool _initDShotEncoder(); // --- PACKET MANAGEMENT --- dshot_packet_t _buildDShotPacket(const uint16_t value); uint16_t _parseDShotPacket(const dshot_packet_t &packet); uint16_t _calculateCRC(const uint16_t data); // --- FRAME PROCESSING --- dshot_result_t _sendDShotFrame(const dshot_packet_t &packet); bool IRAM_ATTR _encodeDShotFrame(const dshot_packet_t &packet, rmt_symbol_word_t *symbols); uint16_t _decodeDShotFrame(const rmt_symbol_word_t *symbols); // --- TIMING CONTROL --- bool IRAM_ATTR _timer_signal(); bool _timer_reset(); // -- CALLBACKS --- QueueHandle_t _rx_queue; rmt_rx_event_callbacks_t _rx_event_callbacks; static bool IRAM_ATTR _rmt_rx_done_callback(rmt_channel_handle_t rmt_rx_channel, const rmt_rx_done_event_data_t *edata, void *user_data); // --- DSHOT DEFAULTS --- static constexpr auto DSHOT_TELEMETRY_INVALID = (0xffff); // --- ERROR HANDLING & LOGGING --- void _dshot_log(const char *msg, Stream &output = Serial) const { output.println(msg); } // --- CONSTANTS & ERROR MESSAGES --- static constexpr bool DSHOT_OK = 0; static constexpr bool DSHOT_ERROR = 1; static constexpr char *NEW_LINE = " "; static constexpr char *UNKNOWN_ERROR = "Unknown Error!"; static constexpr char *TX_INIT_FAILED = "Failed to initialize TX channel!"; static constexpr char *RX_INIT_FAILED = "Failed to initialize RX channel!"; static constexpr char *ENCODER_INIT_FAILED = "Failed to initialize DShot encoder!"; static constexpr char *CRC_CHECK_FAILED = "RX CRC Check failed!"; static constexpr char *THROTTLE_NOT_IN_RANGE = "Throttle value not in range (48 - 2047)!"; static constexpr char *COMMAND_NOT_VALID = "Not a valid DShot Command (0 - 47)!"; static constexpr char *BIDIR_NOT_ENABLED = "Bidirectional DShot support not enabled!"; static constexpr char *RX_RMT_RECEIVER_ERROR = "RX RMT receiver error!"; static constexpr char *PACKET_BUILD_ERROR = "Value too big for DShot Packet!"; static constexpr char *TRANSMITTER_ERROR = "RMT TX Transmitter Error!"; static constexpr char *INIT_SUCCESS = "DShotRMT initialized successfully"; static constexpr char *TELEMETRY_SUCCESS = "Telemetry read successfully"; static constexpr char *TELEMETRY_TIMEOUT = "Telemetry read timeout"; static constexpr char *TRANSMISSION_SUCCESS = "Transmission successful"; };