diff --git a/libraries/AP_CRSF/AP_CRSF_Protocol.cpp b/libraries/AP_CRSF/AP_CRSF_Protocol.cpp
new file mode 100644
index 0000000000..47c41b946f
--- /dev/null
+++ b/libraries/AP_CRSF/AP_CRSF_Protocol.cpp
@@ -0,0 +1,77 @@
+/*
+ * This file is free software: you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License as published by the
+ * Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This file is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
+ * See the GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License along
+ * with this program. If not, see .
+ */
+
+#include "AP_CRSF_Protocol.h"
+
+#if AP_CRSF_ENABLED
+
+// get printable name for frame type (for debug)
+const char* AP_CRSF_Protocol::get_frame_type(uint8_t byte, uint8_t subtype)
+{
+ switch (byte) {
+ case CRSF_FRAMETYPE_GPS:
+ return "GPS";
+ case CRSF_FRAMETYPE_BATTERY_SENSOR:
+ return "BATTERY";
+ case CRSF_FRAMETYPE_HEARTBEAT:
+ return "HEARTBEAT";
+ case CRSF_FRAMETYPE_VTX:
+ return "VTX";
+ case CRSF_FRAMETYPE_VTX_TELEM:
+ return "VTX_TELEM";
+ case CRSF_FRAMETYPE_PARAM_DEVICE_PING:
+ return "PING";
+ case CRSF_FRAMETYPE_COMMAND:
+ return "COMMAND";
+ case CRSF_FRAMETYPE_ATTITUDE:
+ return "ATTITUDE";
+ case CRSF_FRAMETYPE_FLIGHT_MODE:
+ return "FLIGHT_MODE";
+ case CRSF_FRAMETYPE_PARAM_DEVICE_INFO:
+ return "DEVICE_INFO";
+ case CRSF_FRAMETYPE_PARAMETER_READ:
+ return "PARAM_READ";
+ case CRSF_FRAMETYPE_PARAMETER_SETTINGS_ENTRY:
+ return "SETTINGS_ENTRY";
+ case CRSF_FRAMETYPE_LINK_STATISTICS:
+ return "LINK_STATS";
+ case CRSF_FRAMETYPE_RC_CHANNELS_PACKED:
+ return "RC";
+ case CRSF_FRAMETYPE_SUBSET_RC_CHANNELS_PACKED:
+ return "RCv3";
+ case CRSF_FRAMETYPE_RC_CHANNELS_PACKED_11BIT:
+ return "RCv3_11BIT";
+ case CRSF_FRAMETYPE_LINK_STATISTICS_RX:
+ return "LINK_STATSv3_RX";
+ case CRSF_FRAMETYPE_LINK_STATISTICS_TX:
+ return "LINK_STATSv3_TX";
+ case CRSF_FRAMETYPE_PARAMETER_WRITE:
+ return "PARAM_WRITE";
+ case CRSF_FRAMETYPE_AP_CUSTOM_TELEM_LEGACY:
+ case CRSF_FRAMETYPE_AP_CUSTOM_TELEM:
+ switch (subtype) {
+ case CRSF_AP_CUSTOM_TELEM_SINGLE_PACKET_PASSTHROUGH:
+ return "AP_CUSTOM_SINGLE";
+ case CRSF_AP_CUSTOM_TELEM_STATUS_TEXT:
+ return "AP_CUSTOM_TEXT";
+ case CRSF_AP_CUSTOM_TELEM_MULTI_PACKET_PASSTHROUGH:
+ return "AP_CUSTOM_MULTI";
+ }
+ return "AP_CUSTOM";
+ }
+ return "UNKNOWN";
+}
+
+#endif // AP_CRSF_ENABLED
diff --git a/libraries/AP_CRSF/AP_CRSF_Protocol.h b/libraries/AP_CRSF/AP_CRSF_Protocol.h
new file mode 100644
index 0000000000..f9b4828c11
--- /dev/null
+++ b/libraries/AP_CRSF/AP_CRSF_Protocol.h
@@ -0,0 +1,196 @@
+/*
+ * This file is free software: you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License as published by the
+ * Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This file is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
+ * See the GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License along
+ * with this program. If not, see .
+ */
+
+/*
+ * Crossfire protocol definitions - shared between AP_RCProtocol_CRSF and AP_CRSF_Telem
+ * Crossfire constants provided by Team Black Sheep under terms of the 2-Clause BSD License
+ */
+#pragma once
+
+#include "AP_CRSF_config.h"
+
+#if AP_CRSF_ENABLED
+
+#include
+#include
+
+#define CRSF_MAX_CHANNELS 24U // Maximum number of channels from crsf datastream
+#define CRSF_FRAMELEN_MAX 64U // maximum possible framelength
+#define CRSF_HEADER_LEN 2U // header length
+#define CRSF_FRAME_PAYLOAD_MAX (CRSF_FRAMELEN_MAX - CRSF_HEADER_LEN) // maximum size of the frame length field in a packet
+
+class AP_CRSF_Protocol {
+public:
+
+ enum FrameType {
+ CRSF_FRAMETYPE_GPS = 0x02,
+ CRSF_FRAMETYPE_VARIO = 0x07,
+ CRSF_FRAMETYPE_BATTERY_SENSOR = 0x08,
+ CRSF_FRAMETYPE_BARO_VARIO = 0x09,
+ CRSF_FRAMETYPE_HEARTBEAT = 0x0B,
+ CRSF_FRAMETYPE_VTX = 0x0F,
+ CRSF_FRAMETYPE_VTX_TELEM = 0x10,
+ CRSF_FRAMETYPE_LINK_STATISTICS = 0x14,
+ CRSF_FRAMETYPE_RC_CHANNELS_PACKED = 0x16,
+ CRSF_FRAMETYPE_SUBSET_RC_CHANNELS_PACKED = 0x17,
+ CRSF_FRAMETYPE_RC_CHANNELS_PACKED_11BIT = 0x18,
+ CRSF_FRAMETYPE_LINK_STATISTICS_RX = 0x1C,
+ CRSF_FRAMETYPE_LINK_STATISTICS_TX = 0x1D,
+ CRSF_FRAMETYPE_ATTITUDE = 0x1E,
+ CRSF_FRAMETYPE_FLIGHT_MODE = 0x21,
+ // Extended Header Frames, range: 0x28 to 0x96
+ CRSF_FRAMETYPE_PARAM_DEVICE_PING = 0x28,
+ CRSF_FRAMETYPE_PARAM_DEVICE_INFO = 0x29,
+ CRSF_FRAMETYPE_PARAMETER_SETTINGS_ENTRY = 0x2B,
+ CRSF_FRAMETYPE_PARAMETER_READ = 0x2C,
+ CRSF_FRAMETYPE_PARAMETER_WRITE = 0x2D,
+ CRSF_FRAMETYPE_COMMAND = 0x32,
+ // Custom Telemetry Frames 0x7F,0x80
+ CRSF_FRAMETYPE_AP_CUSTOM_TELEM_LEGACY = 0x7F, // as suggested by Remo Masina for fw < 4.06
+ CRSF_FRAMETYPE_AP_CUSTOM_TELEM = 0x80, // reserved for ArduPilot by TBS, requires fw >= 4.06
+ };
+
+ // Command IDs for CRSF_FRAMETYPE_COMMAND
+ enum CommandID {
+ CRSF_COMMAND_FC = 0x01,
+ CRSF_COMMAND_BLUETOOTH = 0x03,
+ CRSF_COMMAND_OSD = 0x05,
+ CRSF_COMMAND_VTX = 0x08,
+ CRSF_COMMAND_LED = 0x09,
+ CRSF_COMMAND_GENERAL = 0x0A,
+ CRSF_COMMAND_RX = 0x10,
+ CRSF_COMMAND_ACK = 0xFF,
+ };
+
+ enum DeviceAddress {
+ CRSF_ADDRESS_BROADCAST = 0x00,
+ CRSF_ADDRESS_USB = 0x10,
+ CRSF_ADDRESS_TBS_CORE_PNP_PRO = 0x80,
+ CRSF_ADDRESS_RESERVED1 = 0x8A,
+ CRSF_ADDRESS_PNP_PRO_CURRENT_SENSOR = 0xC0,
+ CRSF_ADDRESS_PNP_PRO_GPS = 0xC2,
+ CRSF_ADDRESS_TBS_BLACKBOX = 0xC4,
+ CRSF_ADDRESS_FLIGHT_CONTROLLER = 0xC8,
+ CRSF_ADDRESS_RESERVED2 = 0xCA,
+ CRSF_ADDRESS_RACE_TAG = 0xCC,
+ CRSF_ADDRESS_VTX = 0xCE,
+ CRSF_ADDRESS_RADIO_TRANSMITTER = 0xEA,
+ CRSF_ADDRESS_CRSF_RECEIVER = 0xEC,
+ CRSF_ADDRESS_CRSF_TRANSMITTER = 0xEE
+ };
+
+ // Commands for CRSF_COMMAND_GENERAL
+ enum CommandGeneral {
+ CRSF_COMMAND_GENERAL_CHILD_DEVICE_REQUEST = 0x04,
+ CRSF_COMMAND_GENERAL_CHILD_DEVICE_FRAME = 0x05,
+ CRSF_COMMAND_GENERAL_FIRMWARE_UPDATE_BOOTLOADER = 0x0A,
+ CRSF_COMMAND_GENERAL_FIRMWARE_UPDATE_ERASE = 0x0B,
+ CRSF_COMMAND_GENERAL_WRITE_SERIAL_NUMBER = 0x13,
+ CRSF_COMMAND_GENERAL_USER_ID = 0x15,
+ CRSF_COMMAND_GENERAL_SOFTWARE_PRODUCT_KEY = 0x60,
+ CRSF_COMMAND_GENERAL_CRSF_SPEED_PROPOSAL = 0x70, // proposed new CRSF port speed
+ CRSF_COMMAND_GENERAL_CRSF_SPEED_RESPONSE = 0x71, // response to the proposed CRSF port speed
+ };
+
+ // Commands for CRSF_COMMAND_VTX
+ enum CommandVTX {
+ CRSF_COMMAND_VTX_CHANNEL = 0x01,
+ CRSF_COMMAND_VTX_FREQ = 0x02,
+ CRSF_COMMAND_VTX_POWER = 0x03,
+ CRSF_COMMAND_VTX_PITMODE = 0x04,
+ CRSF_COMMAND_VTX_PITMODE_POWERUP = 0x05,
+ CRSF_COMMAND_VTX_POWER_DBM = 0x08,
+ };
+
+ // Commands for CRSF_COMMAND_RX
+ enum CommandRX {
+ CRSF_COMMAND_RX_BIND = 0x01,
+ CRSF_COMMAND_RX_CANCEL_BIND = 0x02,
+ CRSF_COMMAND_RX_SET_BIND_ID = 0x03,
+ };
+
+ // SubType IDs for CRSF_FRAMETYPE_CUSTOM_TELEM
+ enum CustomTelemSubTypeID : uint8_t {
+ CRSF_AP_CUSTOM_TELEM_SINGLE_PACKET_PASSTHROUGH = 0xF0,
+ CRSF_AP_CUSTOM_TELEM_STATUS_TEXT = 0xF1,
+ CRSF_AP_CUSTOM_TELEM_MULTI_PACKET_PASSTHROUGH = 0xF2,
+ };
+
+ enum class ProtocolType {
+ PROTOCOL_CRSF,
+ PROTOCOL_TRACER,
+ PROTOCOL_ELRS
+ };
+
+ struct Frame {
+ uint8_t device_address;
+ uint8_t length;
+ uint8_t type;
+ uint8_t payload[CRSF_FRAME_PAYLOAD_MAX - 1]; // type is already accounted for
+ } PACKED;
+
+ struct SubsetChannelsFrame {
+#if __BYTE_ORDER__ != __ORDER_LITTLE_ENDIAN__
+#error "Only supported on little-endian architectures"
+#endif
+ uint8_t starting_channel:5; // which channel number is the first one in the frame
+ uint8_t res_configuration:2; // configuration for the RC data resolution (10 - 13 bits)
+ uint8_t digital_switch_flag:1; // configuration bit for digital channel
+ uint8_t channels[CRSF_FRAME_PAYLOAD_MAX - 2]; // payload less byte above
+ // uint16_t channel[]:res; // variable amount of channels (with variable resolution based
+ // on the res_configuration) based on the frame size
+ // uint16_t digital_switch_channel[]:10; // digital switch channel
+ } PACKED;
+
+ struct LinkStatisticsTXFrame {
+ uint8_t rssi_db; // RSSI(dBm*-1)
+ uint8_t rssi_percent; // RSSI in percent
+ uint8_t link_quality; // Package success rate / Link quality ( % )
+ int8_t snr; // SNR(dB)
+ uint8_t rf_power_db; // rf power in dBm
+ uint8_t fps; // rf frames per second (fps / 10)
+ } PACKED;
+
+ // CRSF_FRAMETYPE_HEARTBEAT
+ struct HeartbeatFrame {
+ uint8_t origin; // Device address
+ };
+
+ // CRSF_FRAMETYPE_COMMAND
+ struct PACKED CommandFrame {
+ uint8_t destination;
+ uint8_t origin;
+ uint8_t command_id;
+ uint8_t payload[9]; // 8 maximum for LED command + crc8
+ };
+
+ // CRSF_FRAMETYPE_PARAM_DEVICE_PING
+ struct PACKED ParameterPingFrame {
+ uint8_t destination;
+ uint8_t origin;
+ };
+
+ // CRSF_FRAMETYPE_PARAM_DEVICE_INFO
+ struct PACKED ParameterDeviceInfoFrame {
+ uint8_t destination;
+ uint8_t origin;
+ uint8_t payload[58]; // largest possible frame is 60
+ };
+
+ // get printable name for frame type (for debug)
+ static const char* get_frame_type(uint8_t byte, uint8_t subtype = 0);
+};
+
+#endif // AP_CRSF_ENABLED
diff --git a/libraries/AP_CRSF/AP_CRSF_config.h b/libraries/AP_CRSF/AP_CRSF_config.h
new file mode 100644
index 0000000000..5daa2daf14
--- /dev/null
+++ b/libraries/AP_CRSF/AP_CRSF_config.h
@@ -0,0 +1,22 @@
+/*
+ * This file is free software: you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License as published by the
+ * Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This file is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
+ * See the GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License along
+ * with this program. If not, see .
+ */
+
+#pragma once
+
+#include
+
+#ifndef AP_CRSF_ENABLED
+#define AP_CRSF_ENABLED AP_RCPROTOCOL_CRSF_ENABLED
+#endif