115 lines
3.7 KiB
C++
115 lines
3.7 KiB
C++
/**
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* @file DShotRMT.h
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* @brief DShot signal generation using ESP32 RMT with continuous repeat and pause between frames, including BiDirectional support
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* @author Wastl Kraus
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* @date 2025-06-11
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* @license MIT
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*/
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#pragma once
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#include <Arduino.h>
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#include <dshot_commands.h>
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#include <driver/gpio.h>
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#include <driver/rmt_tx.h>
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#include <driver/rmt_rx.h>
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// --- DShot Protocol Constants ---
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// Constants to define timing and encoding rules for DShot Protocol
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static constexpr auto DSHOT_THROTTLE_FAILSAVE = 0;
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static constexpr auto DSHOT_THROTTLE_MIN = 48;
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static constexpr auto DSHOT_THROTTLE_MAX = 2047;
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static constexpr auto DSHOT_BITS_PER_FRAME = 16;
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static constexpr auto PAUSE_BITS = 21;
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static constexpr auto SWITCH_PAUSE = 4;
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static constexpr auto DSHOT_NULL_PACKET = 0b0000000000000000;
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static constexpr auto DSHOT_FULL_PACKET = 0b1111111111111111;
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static constexpr auto NO_ERPM_SIGNAL = 0;
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// RMT configuration parameters
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static constexpr auto DSHOT_CLOCK_SRC_DEFAULT = RMT_CLK_SRC_DEFAULT;
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static constexpr auto DSHOT_RMT_RESOLUTION = 10 * 1000 * 1000; // 10 MHz Clock
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static constexpr auto TX_BUFFER_SIZE = DSHOT_BITS_PER_FRAME;
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static constexpr auto RX_BUFFER_SIZE = 32; // Padding for RX decoding
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// --- DShot Mode Selection ---
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// Select the appropriate bit timing for the protocol
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typedef enum dshot_mode_e
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{
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DSHOT_OFF,
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DSHOT150,
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DSHOT300,
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DSHOT600,
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DSHOT1200
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} dshot_mode_t;
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// --- DShotRMT Class ---
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// This class provides an abstraction for sending and optionally receiving DShot frames.
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// It uses ESP32's RMT peripheral for precise timing control, including BiDirectional RX.
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class DShotRMT
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{
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public:
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// Constructor: initializes configuration state
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DShotRMT(gpio_num_t gpio, dshot_mode_t mode = DSHOT300, bool isBidirectional = false);
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// Initializes the RMT TX and RX channels
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void begin();
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// Sets a new throttle value (48-2047) and sends it repeatedly
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void setThrottle(uint16_t throttle);
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// Receives and decodes the latest value from ESC, if available
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uint32_t getERPM();
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uint32_t getMotorRPM(uint8_t magnet_count);
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// Accessors for GPIO and DShot mode
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gpio_num_t getGPIO() const { return _gpio; }
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dshot_mode_t getDShotMode() const { return _mode; }
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private:
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// Calculate the checksum for throttle value
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uint16_t calculateCRC(uint16_t dshot_packet);
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// Assamble DShot Paket (10 bit throttle + 1 bit telemetry request + 4 bit crc)
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uint16_t assambleDShotPaket(uint16_t value);
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// Converts a 16-bit DShot packet into RMT symbols and appends pause
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void encodeDShotTX(uint16_t dshot_packet, rmt_symbol_word_t *symbols, size_t &count);
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// Decodes the ESC answer
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uint16_t decodeDShotRX(const rmt_symbol_word_t *symbols, uint32_t count);
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// --- Configuration Parameter ---
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gpio_num_t _gpio;
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dshot_mode_t _mode;
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bool _isBidirectional;
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// --- DShot Packets Container ---
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uint16_t _lastThrottle = DSHOT_FULL_PACKET;
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uint16_t _received_packet = DSHOT_NULL_PACKET;
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uint16_t _tx_packet = DSHOT_NULL_PACKET;
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uint16_t _packet_crc = 0;
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// --- RMT Channel ---
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rmt_channel_handle_t _rmt_rx_channel = nullptr;
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rmt_channel_handle_t _rmt_tx_channel = nullptr;
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rmt_rx_channel_config_t _rmt_rx_channel_config = {};
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rmt_tx_channel_config_t _rmt_tx_channel_config = {};
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// --- DShot RMT Encoder ---
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rmt_encoder_handle_t _dshot_encoder = nullptr;
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// --- RMT Configuration ---
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rmt_receive_config_t _receive_config = {};
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rmt_transmit_config_t _transmit_config = {};
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// --- RMT Symbol Buffer ---
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rmt_symbol_word_t _rx_symbols[RX_BUFFER_SIZE] = {};
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rmt_symbol_word_t _tx_symbols[TX_BUFFER_SIZE] = {};
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// Stores the last valid eRPM received from the ESC
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uint16_t _last_erpm = 0;
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};
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