diff --git a/DShotRMT.cpp b/DShotRMT.cpp index 0d00a66..4fcaa1f 100644 --- a/DShotRMT.cpp +++ b/DShotRMT.cpp @@ -12,8 +12,18 @@ // This class provides an abstraction for sending and optionally receiving DShot frames. // It uses ESP32's RMT peripheral for precise timing control, including BiDirectional RX. -DShotRMT::DShotRMT(gpio_num_t gpio, dshot_mode_t mode, bool isBidirectional, uint8_t pauseDuration) - : _gpio(gpio), _mode(mode), _isBidirectional(isBidirectional), _pauseDuration(pauseDuration) {} +DShotRMT::DShotRMT(gpio_num_t gpio, dshot_mode_t mode, bool isBidirectional) + : _gpio(gpio), _mode(mode), _isBidirectional(isBidirectional) +{ + // Fixed Timings for compatibility + _frame_time = dshot_times.frameLength + DSHOT_SWITCH_TIME; + + // DShot Frame answer padding + if (_isBidirectional) + { + _frame_time += _frame_time; + } +} // Initializes RMT TX and RX channels and encoder configuration void DShotRMT::begin() @@ -25,7 +35,7 @@ void DShotRMT::begin() .gpio_num = _gpio, .clk_src = DSHOT_CLOCK_SRC_DEFAULT, .resolution_hz = DSHOT_RMT_RESOLUTION, - .mem_block_symbols = 64, + .mem_block_symbols = DSHOT_SYMBOLS_SIZE, }; if (rmt_new_rx_channel(&_rmt_rx_channel_config, &_rmt_rx_channel) != 0) @@ -33,6 +43,7 @@ void DShotRMT::begin() Serial.println("Failed to create RX channel"); return; } + if (rmt_enable(_rmt_rx_channel) != 0) { Serial.println("Failed to enable RX channel"); @@ -48,12 +59,11 @@ void DShotRMT::begin() .gpio_num = _gpio, .clk_src = DSHOT_CLOCK_SRC_DEFAULT, .resolution_hz = DSHOT_RMT_RESOLUTION, - .mem_block_symbols = 64, - .trans_queue_depth = 10, - }; + .mem_block_symbols = DSHOT_SYMBOLS_SIZE, + .trans_queue_depth = TX_BUFFER_SIZE}; // Transmission configuration - _transmit_config.loop_count = 0; + _transmit_config.loop_count = NULL; _transmit_config.flags.eot_level = _isBidirectional; if (rmt_new_tx_channel(&_rmt_tx_channel_config, &_rmt_tx_channel) != 0) @@ -61,6 +71,7 @@ void DShotRMT::begin() Serial.println("Failed to create TX channel"); return; } + if (rmt_enable(_rmt_tx_channel) != 0) { Serial.println("Failed to enable TX channel"); @@ -82,27 +93,33 @@ void DShotRMT::begin() // Encodes and transmits a valid DShot throttle value (48 - 2047) void DShotRMT::setThrottle(uint16_t throttle) { - // Clamp input range and mask to 11 bits - throttle = constrain(throttle, DSHOT_THROTTLE_MIN, DSHOT_THROTTLE_MAX) & 0x7FF; + // Simple timer + static unsigned long last_time = NULL; - _lastThrottle = throttle; + // + dshot_packet_t packet = {}; - // Convert throttle value to DShot packet format - _tx_packet = assambleDShotPaket(_lastThrottle); + packet.throttle_value = (constrain(throttle, DSHOT_THROTTLE_MIN, DSHOT_THROTTLE_MAX) & 0b0000011111111111); + packet.telemetric_request = _isBidirectional; + packet.checksum = calculateCRC(packet); - // Encode RMT symbols - size_t count = 0; - encodeDShotTX(_tx_packet, _tx_symbols, count); + // DShot transcoding + rmt_symbol_word_t tx_symbols[DSHOT_BITS_PER_FRAME] = {}; + encodeDShotTX(packet, tx_symbols); - // Transmit the packet - if (rmt_transmit(_rmt_tx_channel, _dshot_encoder, _tx_symbols, count * sizeof(rmt_symbol_word_t), &_transmit_config) != 0) + // Ensure frame lenght for compatibility + if (micros() - last_time >= _frame_time) { - Serial.println("Failed to transmit DShot packet"); - return; - } + // Transmit the packet + if (rmt_transmit(_rmt_tx_channel, _dshot_encoder, tx_symbols, DSHOT_SYMBOLS_SIZE, &_transmit_config) != 0) + { + Serial.println("Failed to transmit DShot packet"); + return; + } - // Pause between frames - esp_rom_delay_us(_pauseDuration); + // Timestamp + last_time = micros(); + } } // Receives and decodes a response frame from ESC containing eRPM info @@ -111,13 +128,17 @@ uint32_t DShotRMT::getERPM() if (_isBidirectional) { if (_rmt_rx_channel == nullptr) + { Serial.println("No bidirectional DShot support."); return _last_erpm; + } // Try to receive a new frame - if (!rmt_receive(_rmt_rx_channel, _rx_symbols, sizeof(_rx_symbols), &_receive_config)) + if (!rmt_receive(_rmt_rx_channel, _rx_symbols, DSHOT_SYMBOLS_SIZE, &_receive_config)) + { Serial.println("No valid DShot frame received"); return _last_erpm; + } _last_erpm = decodeDShotRX(_rx_symbols, DSHOT_BITS_PER_FRAME); return _last_erpm; @@ -138,100 +159,53 @@ uint32_t DShotRMT::getMotorRPM(uint8_t magnet_count) } // Calculates CRC for DShot packet -uint16_t DShotRMT::calculateCRC(uint16_t dshot_packet) +uint16_t DShotRMT::calculateCRC(dshot_packet_t dshot_packet) { - uint16_t packet = (dshot_packet << 1) | (_isBidirectional ? 1 : 0); - - // Reset CRC container - _packet_crc = DSHOT_NULL_PACKET; + uint16_t crc = (dshot_packet.throttle_value << 1) | (dshot_packet.telemetric_request); // CRC calculation for DShot (4 bits) - _packet_crc = ((packet ^ (packet >> 4) ^ (packet >> 8)) & 0xF); + dshot_packet.checksum = ((crc ^ (crc >> 4) ^ (crc >> 8)) & 0b0000000000001111); // CRC is inverted for bidirectional DShot - if (_isBidirectional) - _packet_crc = (~_packet_crc) & 0xF; + if (dshot_packet.telemetric_request) + dshot_packet.checksum = (~dshot_packet.checksum) & 0b0000000000001111; - return _packet_crc; + return dshot_packet.checksum; } // Assembles DShot packet (11 bit throttle + 1 bit telemetry request + 4 bit CRC) -uint16_t DShotRMT::assambleDShotPaket(uint16_t value) +uint16_t DShotRMT::parseDShotPacket(const dshot_packet_t dshot_packet) { - uint16_t throttle = value & 0x7FF; - - // Reset packet container - _tx_packet = DSHOT_NULL_PACKET; - - // Assemble raw DShot packet and add checksum - _packet_crc = calculateCRC(throttle); - - _tx_packet = (throttle << 1) | (_isBidirectional ? 1 : 0); - _tx_packet = (_tx_packet << 4) | _packet_crc; - - return _tx_packet; + uint16_t raw = (((dshot_packet.throttle_value << 1) | (dshot_packet.telemetric_request)) & 0b0000111111111111); + return (((raw << 4) | (dshot_packet.checksum)) & 0b1111111111111111); } // Converts a 16-bit packet into a valid DShot frame for RMT -void DShotRMT::encodeDShotTX(uint16_t dshot_packet, rmt_symbol_word_t *symbols, size_t &count) +void DShotRMT::encodeDShotTX(dshot_packet_t dshot_packet, rmt_symbol_word_t *symbols) { - count = 0; + // Encoding to "raw" DShot Packet + uint16_t frame_bits = parseDShotPacket(dshot_packet); - uint32_t ticks_per_bit = 0; - uint32_t ticks_zero_high = 0; - uint32_t ticks_one_high = 0; + // Always start with the "first" bit + size_t count = NULL; - // Select timing based on DShot mode - switch (_mode) + // Convert the parsed dshot frame to rmt_tx data + for (int i = DSHOT_BITS_PER_FRAME - 1; i >= 0; i--) { - case DSHOT150: - ticks_per_bit = 64; - ticks_zero_high = 24; - ticks_one_high = 48; - break; - case DSHOT300: - ticks_per_bit = 32; - ticks_zero_high = 12; - ticks_one_high = 24; - break; - case DSHOT600: - ticks_per_bit = 16; - ticks_zero_high = 6; - ticks_one_high = 12; - break; - case DSHOT1200: - ticks_per_bit = 8; - ticks_zero_high = 3; - ticks_one_high = 6; - break; - case DSHOT_OFF: - default: - ticks_per_bit = 0; - ticks_zero_high = 0; - ticks_one_high = 0; - break; - } - - uint32_t ticks_zero_low = ticks_per_bit - ticks_zero_high; - uint32_t ticks_one_low = ticks_per_bit - ticks_one_high; - - // Fill the 16 DShot bits array with selected timings - for (int i = 15; i >= 0; i--) - { - bool bit = (dshot_packet >> i) & 0x1; + bool bit = (frame_bits >> i) & 0b0000000000000001; if (_isBidirectional) { symbols[count].level0 = 0; - symbols[count].duration0 = bit ? ticks_one_high : ticks_zero_high; + symbols[count].duration0 = bit ? dshot_times.ticks_one_high : dshot_times.ticks_zero_high; symbols[count].level1 = 1; - symbols[count].duration1 = bit ? ticks_one_low : ticks_zero_low; + symbols[count].duration1 = bit ? dshot_times.ticks_one_low : dshot_times.ticks_zero_low; } else { symbols[count].level0 = 1; - symbols[count].duration0 = bit ? ticks_one_high : ticks_zero_high; + symbols[count].duration0 = bit ? dshot_times.ticks_one_high : dshot_times.ticks_zero_high; symbols[count].level1 = 0; - symbols[count].duration1 = bit ? ticks_one_low : ticks_zero_low; + symbols[count].duration1 = bit ? dshot_times.ticks_one_low : dshot_times.ticks_zero_low; } count++; } @@ -251,12 +225,12 @@ uint16_t DShotRMT::decodeDShotRX(const rmt_symbol_word_t *symbols, uint32_t coun // Extract CRC and payload uint16_t payload = received_frame >> 4; - uint8_t crc_received = received_frame & 0xF; + uint8_t crc_received = received_frame & 0b0000000000001111; // Calculate CRC for received frame - uint8_t crc_calculated = (payload ^ (payload >> 4) ^ (payload >> 8)) & 0xF; + uint8_t crc_calculated = (payload ^ (payload >> 4) ^ (payload >> 8)) & 0b0000000000001111; if (_isBidirectional) - crc_calculated = (~crc_calculated) & 0xF; + crc_calculated = (~crc_calculated) & 0b0000000000001111; // Check CRC if (crc_received != crc_calculated) @@ -265,8 +239,6 @@ uint16_t DShotRMT::decodeDShotRX(const rmt_symbol_word_t *symbols, uint32_t coun return _last_erpm; } - // Remove telemetry bit, keep raw value - uint16_t raw = payload >> 1; - - return _last_erpm = raw; + // Remove telemetry bit + return _last_erpm = payload >> 1; } diff --git a/DShotRMT.h b/DShotRMT.h index a512525..6cc0ece 100644 --- a/DShotRMT.h +++ b/DShotRMT.h @@ -14,25 +14,16 @@ #include #include +static constexpr bool DSHOT_OK = 0; +static constexpr bool DSHOT_FAILED = 1; + // --- DShot Protocol Constants --- static constexpr uint16_t DSHOT_THROTTLE_FAILSAVE = 0; static constexpr uint16_t DSHOT_THROTTLE_MIN = 48; static constexpr uint16_t DSHOT_THROTTLE_MAX = 2047; -static constexpr uint8_t DSHOT_BITS_PER_FRAME = 16; - -static constexpr uint16_t DSHOT_NULL_PACKET = 0x0000; -static constexpr uint16_t DSHOT_FULL_PACKET = 0xFFFF; -static constexpr uint16_t NO_ERPM_SIGNAL = 0; - -// RMT configuration parameters -static constexpr rmt_clock_source_t DSHOT_CLOCK_SRC_DEFAULT = RMT_CLK_SRC_DEFAULT; -static constexpr uint32_t DSHOT_RMT_RESOLUTION = 10 * 1000 * 1000; // 10 MHz Clock - -static constexpr size_t TX_BUFFER_SIZE = DSHOT_BITS_PER_FRAME; -static constexpr size_t RX_BUFFER_SIZE = 32; // Padding for RX decoding // DShot Packet structure -typedef struct +typedef struct dshot_packet_s { uint16_t throttle_value : 11; bool telemetric_request : 1; @@ -40,7 +31,7 @@ typedef struct } dshot_packet_t; // --- DShot Mode Selection --- -typedef enum +typedef enum dshot_mode_s { DSHOT_OFF, DSHOT150, @@ -49,12 +40,33 @@ typedef enum DSHOT1200 } dshot_mode_t; +// --- DShot Timings --- +typedef struct dshot_timing_s +{ + uint16_t frameLength; + uint16_t ticks_per_bit; + uint16_t ticks_one_high; + uint16_t ticks_zero_high; + uint16_t ticks_zero_low; + uint16_t ticks_one_low; +} dshot_timing_t; + +// DShot Pulse Length Settings +const dshot_timing_t dshot_timings[] = { + {0, 0, 0, 0, 0, 0}, // DSHOT_OFF + {128, 64, 48, 24, 40, 16}, // DSHOT150 + {64, 32, 24, 12, 20, 8}, // DSHOT300 + {32, 16, 12, 6, 10, 4}, // DSHOT600 + {16, 8, 6, 3, 5, 2} // DSHOT1200 +}; + +// // --- DShotRMT Class --- class DShotRMT { public: // Constructor: initializes configuration state - DShotRMT(gpio_num_t gpio, dshot_mode_t mode = DSHOT300, bool isBidirectional = false, uint8_t pauseDuration = 120); + DShotRMT(gpio_num_t gpio, dshot_mode_t mode = DSHOT300, bool isBidirectional = false); // Initializes the RMT TX and RX channels void begin(); @@ -69,33 +81,44 @@ public: // Accessors for GPIO and DShot settings gpio_num_t getGPIO() const { return _gpio; } dshot_mode_t getDShotMode() const { return _mode; } - uint8_t getPauseDuration() const { return _pauseDuration; } - void setPauseDuration(uint8_t pauseDuration) { _pauseDuration = pauseDuration; } + + // --- Configuration Parameters --- + gpio_num_t _gpio = GPIO_NUM_NC; + dshot_mode_t _mode = DSHOT_OFF; + bool _isBidirectional = false; + uint16_t _frame_time; + const dshot_timing_t &dshot_times = dshot_timings[_mode]; private: - // Calculates the checksum for a DShot packet - uint16_t calculateCRC(uint16_t dshot_packet); + static constexpr uint8_t DSHOT_BITS_PER_FRAME = 16; + static constexpr uint8_t DSHOT_SWITCH_TIME = 42; - // Assembles DShot packet (11 bit throttle + 1 bit telemetry request + 4 bit CRC) - uint16_t assambleDShotPaket(uint16_t value); + static constexpr uint16_t DSHOT_NULL_PACKET = 0b000000000000000; + static constexpr uint16_t DSHOT_FULL_PACKET = 0b111111111111111; + static constexpr uint16_t NO_ERPM_SIGNAL = 0; + + // RMT configuration parameters + static constexpr rmt_clock_source_t DSHOT_CLOCK_SRC_DEFAULT = RMT_CLK_SRC_DEFAULT; + static constexpr uint32_t DSHOT_RMT_RESOLUTION = 10 * 1000 * 1000; // 10 MHz Clock + + static constexpr size_t TX_BUFFER_SIZE = DSHOT_BITS_PER_FRAME; + static constexpr size_t RX_BUFFER_SIZE = 32; + static constexpr size_t DSHOT_SYMBOLS_SIZE = 64; + + // Calculates the checksum for a DShot packet + uint16_t calculateCRC(dshot_packet_t dshot_packet); + + // Parses the DShot packet (11 bit throttle + 1 bit telemetry request + 4 bit CRC) + uint16_t parseDShotPacket(const dshot_packet_t dshot_packet); // Converts a 16-bit DShot packet into RMT symbols - void encodeDShotTX(uint16_t dshot_packet, rmt_symbol_word_t *symbols, size_t &count); + void encodeDShotTX(dshot_packet_t dshot_packet, rmt_symbol_word_t *symbols); // Decodes the ESC answer uint16_t decodeDShotRX(const rmt_symbol_word_t *symbols, uint32_t count); - // --- Configuration Parameters --- - gpio_num_t _gpio; - dshot_mode_t _mode; - bool _isBidirectional; - uint8_t _pauseDuration; - // --- DShot Packets Container --- - uint16_t _lastThrottle = DSHOT_NULL_PACKET; uint16_t _rx_packet = DSHOT_NULL_PACKET; - uint16_t _tx_packet = DSHOT_NULL_PACKET; - uint8_t _packet_crc = 0; // --- RMT Channel Handles --- rmt_channel_handle_t _rmt_rx_channel = nullptr; @@ -112,8 +135,7 @@ private: // --- RMT Symbol Buffers --- rmt_symbol_word_t _rx_symbols[RX_BUFFER_SIZE] = {}; - rmt_symbol_word_t _tx_symbols[TX_BUFFER_SIZE] = {}; // Stores the last valid eRPM received from the ESC - uint16_t _last_erpm = 0; + uint16_t _last_erpm = NULL; }; diff --git a/README.md b/README.md index a35443c..1fd1186 100644 --- a/README.md +++ b/README.md @@ -114,7 +114,7 @@ Perfect for DShot: ## 📝 API Reference -- `DShotRMT(gpio_num_t gpio, dshot_mode_t mode, bool isBidirectional, uint8_t pauseDuration = 120)` +- `DShotRMT(gpio_num_t gpio, dshot_mode_t mode, bool isBidirectional)` - `void begin()` - `void setThrottle(uint16_t throttle)` - `uint32_t getERPM()` diff --git a/examples/dshot300/dshot300.ino b/examples/dshot300/dshot300.ino index 368ca62..1753da0 100644 --- a/examples/dshot300/dshot300.ino +++ b/examples/dshot300/dshot300.ino @@ -32,6 +32,7 @@ void printRPMPeriodically(uint16_t throttle); // Reads throttle value from serial input uint16_t readSerialThrottle(); +// void setup() { // Start the USB Serial Port @@ -45,9 +46,10 @@ void setup() USB_SERIAL.println("**********************"); USB_SERIAL.println("DShotRMT Demo started."); - USB_SERIAL.println("Enter a throttle value (48–2047):"); + USB_SERIAL.println("Enter a throttle value (48 – 2047):"); } +// void loop() { // Read value input from Serial @@ -73,12 +75,10 @@ uint16_t readSerialThrottle() String input = USB_SERIAL.readStringUntil('\n'); int throttle_input = input.toInt(); - // Clamp the value to the DShot range - throttle_input = constrain(throttle_input, DSHOT_THROTTLE_MIN, DSHOT_THROTTLE_MAX); - if (throttle_input < DSHOT_THROTTLE_MIN || throttle_input > DSHOT_THROTTLE_MAX) { USB_SERIAL.println("Invalid input. Please enter a value between 48 and 2047."); + return last_throttle; } else { @@ -88,7 +88,7 @@ uint16_t readSerialThrottle() } USB_SERIAL.println("*********************************"); - USB_SERIAL.println("Enter a throttle value (48–2047):"); + USB_SERIAL.println("Enter a throttle value (48 – 2047):"); } return last_throttle; @@ -98,17 +98,16 @@ uint16_t readSerialThrottle() void printRPMPeriodically(uint16_t throttle) { static unsigned long last_print_time = 0; - unsigned long now = millis(); - if (now - last_print_time >= 2000) + if (millis() - last_print_time >= 2000) { - last_print_time = now; - uint32_t rpm = motor01.getMotorRPM(MOTOR01_MAGNET_COUNT); USB_SERIAL.print("Throttle: "); USB_SERIAL.print(throttle); USB_SERIAL.print(" | RPM: "); USB_SERIAL.println(rpm); + + last_print_time = millis(); } }