119 lines
3.6 KiB
C++
119 lines
3.6 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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static constexpr uint16_t DSHOT_THROTTLE_FAILSAVE = 0;
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static constexpr uint16_t DSHOT_THROTTLE_MIN = 48;
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static constexpr uint16_t DSHOT_THROTTLE_MAX = 2047;
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static constexpr uint8_t DSHOT_BITS_PER_FRAME = 16;
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static constexpr uint8_t DSHOT_SWITCH_TIME = 21;
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static constexpr uint16_t DSHOT_NULL_PACKET = 0x0000;
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static constexpr uint16_t DSHOT_FULL_PACKET = 0xFFFF;
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static constexpr uint16_t NO_ERPM_SIGNAL = 0;
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// RMT configuration parameters
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static constexpr rmt_clock_source_t DSHOT_CLOCK_SRC_DEFAULT = RMT_CLK_SRC_DEFAULT;
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static constexpr uint32_t DSHOT_RMT_RESOLUTION = 10 * 1000 * 1000; // 10 MHz Clock
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static constexpr size_t TX_BUFFER_SIZE = DSHOT_BITS_PER_FRAME;
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static constexpr size_t RX_BUFFER_SIZE = 32; // Padding for RX decoding
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// DShot Packet structure
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typedef struct dshot_packet_s
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{
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uint16_t throttle_value : 11;
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bool telemetric_request : 1;
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uint8_t checksum : 4;
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} dshot_packet_t;
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// --- DShot Mode Selection ---
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typedef enum dshot_mode_s
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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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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
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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 settings
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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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uint8_t getFrameLenght() const { return _frameLength; }
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protected:
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// Calculates the checksum for a DShot packet
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void calculateCRC(dshot_packet_t *dshot_packet);
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// Parses the DShot packet (11 bit throttle + 1 bit telemetry request + 4 bit CRC)
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uint16_t parseDShotPacket(const dshot_packet_t *dshot_packet) const;
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// Converts a 16-bit DShot packet into RMT symbols
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void encodeDShotTX(dshot_packet_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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private:
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// --- Configuration Parameters ---
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gpio_num_t _gpio = GPIO_NUM_NC;
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dshot_mode_t _mode = DSHOT_OFF;
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bool _isBidirectional = false;
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uint16_t _frameLength = NULL;
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// --- DShot Packets Container ---
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uint16_t _rx_packet = DSHOT_NULL_PACKET;
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dshot_packet_t _dshot_packet = {};
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// --- RMT Channel Handles ---
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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 Buffers ---
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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 = NULL;
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};
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