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517 lines
21 KiB
517 lines
21 KiB
/* |
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Copyright (C) 2021 Kraus Hamdani Aerospace Inc. All rights reserved. |
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This program is free software: you can redistribute it and/or modify |
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it under the terms of the GNU General Public License as published by |
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the Free Software Foundation, either version 3 of the License, or |
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(at your option) any later version. |
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This program is distributed in the hope that it will be useful, |
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but WITHOUT ANY WARRANTY; without even the implied warranty of |
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
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GNU General Public License for more details. |
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You should have received a copy of the GNU General Public License |
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along with this program. If not, see <http://www.gnu.org/licenses/>. |
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Author: Tom Pittenger |
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*/ |
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#include "AP_ADSB_uAvionix_UCP.h" |
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// This driver implements the UCP protocol from uAvionix which is a variant of the GDL90 protocol by Garmin |
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// https://uavionix.com/downloads/ping200X/uAvionix-UCP-Transponder-ICD-Rev-Q.pdf |
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#if HAL_ADSB_UCP_ENABLED |
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#include <AP_SerialManager/AP_SerialManager.h> |
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#include <GCS_MAVLink/GCS.h> |
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#include <AP_HAL/AP_HAL.h> |
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#include <AP_Math/AP_Math.h> |
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#include <AP_Math/crc.h> |
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#include <ctype.h> |
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#include <AP_Notify/AP_Notify.h> |
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extern const AP_HAL::HAL &hal; |
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#define AP_ADSB_UAVIONIX_HEALTH_TIMEOUT_MS (5000UL) |
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#define AP_ADSB_UAVIONIX_GCS_LOST_COMMS_LONG_TIMEOUT_MINUTES (15UL) |
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#define AP_ADSB_UAVIONIX_GCS_LOST_COMMS_LONG_TIMEOUT_MS (1000UL * 60UL * AP_ADSB_UAVIONIX_GCS_LOST_COMMS_LONG_TIMEOUT_MINUTES) |
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#define AP_ADSB_UAVIONIX_DETECT_GROUNDSTATE 0 |
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#define AP_ADSB_UAVIONIX_EMERGENCY_STATUS_ON_LOST_LINK 0 |
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// detect if any port is configured as uAvionix_UCP |
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bool AP_ADSB_uAvionix_UCP::detect() |
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{ |
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return AP::serialmanager().have_serial(AP_SerialManager::SerialProtocol_ADSB, 0); |
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} |
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// Init, called once after class is constructed |
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bool AP_ADSB_uAvionix_UCP::init() |
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{ |
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_port = AP::serialmanager().find_serial(AP_SerialManager::SerialProtocol_ADSB, 0); |
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if (_port == nullptr) { |
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return false; |
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} |
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request_msg(GDL90_ID_IDENTIFICATION); |
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request_msg(GDL90_ID_TRANSPONDER_CONFIG); |
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return true; |
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} |
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void AP_ADSB_uAvionix_UCP::update() |
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{ |
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if (_port == nullptr) { |
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return; |
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} |
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const uint32_t now_ms = AP_HAL::millis(); |
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// ----------------------------- |
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// read any available data on serial port |
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// ----------------------------- |
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uint32_t nbytes = MIN(_port->available(), 10UL * GDL90_RX_MAX_PACKET_LENGTH); |
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while (nbytes-- > 0) { |
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const int16_t data = (uint8_t)_port->read(); |
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if (data < 0) { |
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break; |
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} |
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if (parseByte((uint8_t)data, rx.msg, rx.status)) { |
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rx.last_msg_ms = now_ms; |
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handle_msg(rx.msg); |
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} |
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} // while nbytes |
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if (now_ms - run_state.last_packet_Transponder_Control_ms >= 1000) { |
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run_state.last_packet_Transponder_Control_ms = now_ms; |
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send_Transponder_Control(); |
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} |
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if ((now_ms - run_state.last_packet_GPS_ms >= 200) && (_frontend._options & uint32_t(AP_ADSB::AdsbOption::Ping200X_Send_GPS)) != 0) { |
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run_state.last_packet_GPS_ms = now_ms; |
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send_GPS_Data(); |
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} |
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// if the transponder has stopped giving us the data needed to |
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// fill the transponder status mavlink message, reset that data. |
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if ((now_ms - run_state.last_packet_Transponder_Status_ms >= 10000 && run_state.last_packet_Transponder_Status_ms != 0) |
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&& (now_ms - run_state.last_packet_Transponder_Heartbeat_ms >= 10000 && run_state.last_packet_Transponder_Heartbeat_ms != 0) |
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&& (now_ms - run_state.last_packet_Transponder_Ownship_ms >= 10000 && run_state.last_packet_Transponder_Ownship_ms != 0)) |
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{ |
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_frontend.out_state.tx_status.fault |= UAVIONIX_ADSB_OUT_STATUS_FAULT_STATUS_MESSAGE_UNAVAIL; |
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} |
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} |
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void AP_ADSB_uAvionix_UCP::handle_msg(const GDL90_RX_MESSAGE &msg) |
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{ |
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switch(msg.messageId) { |
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case GDL90_ID_HEARTBEAT: { |
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// The Heartbeat message provides real-time indications of the status and operation of the |
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// transponder. The message will be transmitted with a period of one second for the UCP |
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// protocol. |
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memcpy(&rx.decoded.heartbeat, msg.raw, sizeof(rx.decoded.heartbeat)); |
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run_state.last_packet_Transponder_Heartbeat_ms = AP_HAL::millis(); |
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// this is always true. The "ground/air bit place" is set meaning we're always in the air |
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_frontend.out_state.tx_status.state |= UAVIONIX_ADSB_OUT_STATUS_STATE_ON_GROUND; |
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if (rx.decoded.heartbeat.status.one.maintenanceRequired) { |
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_frontend.out_state.tx_status.fault |= UAVIONIX_ADSB_OUT_STATUS_FAULT_MAINT_REQ; |
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} else { |
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_frontend.out_state.tx_status.fault &= ~UAVIONIX_ADSB_OUT_STATUS_FAULT_MAINT_REQ; |
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} |
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if (rx.decoded.heartbeat.status.two.functionFailureGnssUnavailable) { |
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_frontend.out_state.tx_status.fault |= UAVIONIX_ADSB_OUT_STATUS_FAULT_GPS_UNAVAIL; |
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} else { |
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_frontend.out_state.tx_status.fault &= ~UAVIONIX_ADSB_OUT_STATUS_FAULT_GPS_UNAVAIL; |
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} |
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if (rx.decoded.heartbeat.status.two.functionFailureGnssNo3dFix) { |
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_frontend.out_state.tx_status.fault |= UAVIONIX_ADSB_OUT_STATUS_FAULT_GPS_NO_POS; |
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} else { |
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_frontend.out_state.tx_status.fault &= ~UAVIONIX_ADSB_OUT_STATUS_FAULT_GPS_NO_POS; |
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} |
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if (rx.decoded.heartbeat.status.two.functionFailureTransmitSystem) { |
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_frontend.out_state.tx_status.fault |= UAVIONIX_ADSB_OUT_STATUS_FAULT_TX_SYSTEM_FAIL; |
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} else { |
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_frontend.out_state.tx_status.fault &= ~UAVIONIX_ADSB_OUT_STATUS_FAULT_TX_SYSTEM_FAIL; |
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} |
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_frontend.out_state.tx_status.fault &= ~UAVIONIX_ADSB_OUT_STATUS_FAULT_STATUS_MESSAGE_UNAVAIL; |
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} |
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break; |
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case GDL90_ID_IDENTIFICATION: |
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// The Identification message contains information used to identify the connected device. The |
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// Identification message will be transmitted with a period of one second regardless of data status |
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// or update for the UCP protocol and will be transmitted upon request for the UCP-HD protocol. |
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if (memcmp(&rx.decoded.identification, msg.raw, sizeof(rx.decoded.identification)) != 0) { |
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memcpy(&rx.decoded.identification, msg.raw, sizeof(rx.decoded.identification)); |
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// Firmware Part Number (not null terminated, but null padded if part number is less than 15 characters). |
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// Copy into a temporary string that is 1 char longer so we ensure it's null terminated |
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const uint8_t str_len = sizeof(rx.decoded.identification.primaryFwPartNumber); |
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char primaryFwPartNumber[str_len+1]; |
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memcpy(&primaryFwPartNumber, rx.decoded.identification.primaryFwPartNumber, str_len); |
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primaryFwPartNumber[str_len] = 0; |
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GCS_SEND_TEXT(MAV_SEVERITY_DEBUG,"ADSB:Detected %s v%u.%u.%u SN:%u %s", |
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get_hardware_name(rx.decoded.identification.primary.hwId), |
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(unsigned)rx.decoded.identification.primary.fwMajorVersion, |
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(unsigned)rx.decoded.identification.primary.fwMinorVersion, |
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(unsigned)rx.decoded.identification.primary.fwBuildVersion, |
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(unsigned)rx.decoded.identification.primary.serialNumber, |
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primaryFwPartNumber); |
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} |
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break; |
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case GDL90_ID_TRANSPONDER_CONFIG: |
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memcpy(&rx.decoded.transponder_config, msg.raw, sizeof(rx.decoded.transponder_config)); |
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break; |
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#if AP_ADSB_UAVIONIX_UCP_CAPTURE_ALL_RX_PACKETS |
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case GDL90_ID_OWNSHIP_REPORT: |
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// The Ownship message contains information on the GNSS position. If the Ownship GNSS |
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// position fix is invalid, the Latitude, Longitude, and NIC fields will all have the ZERO value. The |
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// Ownship message will be transmitted with a period of one second regardless of data status or |
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// update for the UCP protocol. All fields in the ownship message are transmitted MSB first |
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memcpy(&rx.decoded.ownship_report, msg.raw, sizeof(rx.decoded.ownship_report)); |
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run_state.last_packet_Transponder_Ownship_ms = AP_HAL::millis(); |
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_frontend.out_state.tx_status.NIC_NACp = rx.decoded.ownship_report.report.NIC | (rx.decoded.ownship_report.report.NACp << 4); |
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memcpy(_frontend.out_state.tx_status.flight_id, rx.decoded.ownship_report.report.callsign, sizeof(_frontend.out_state.tx_status.flight_id)); |
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//_frontend.out_state.tx_status.temperature = rx.decoded.ownship_report.report.temperature; // there is no message in the vocabulary of the 200x that has board temperature |
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break; |
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case GDL90_ID_OWNSHIP_GEOMETRIC_ALTITUDE: |
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// An Ownship Geometric Altitude message will be transmitted with a period of one second when |
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// the GNSS fix is valid for the UCP protocol. All fields in the Geometric Ownship Altitude |
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// message are transmitted MSB first. |
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memcpy(&rx.decoded.ownship_geometric_altitude, msg.raw, sizeof(rx.decoded.ownship_geometric_altitude)); |
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break; |
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case GDL90_ID_SENSOR_MESSAGE: |
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memcpy(&rx.decoded.sensor_message, msg.raw, sizeof(rx.decoded.sensor_message)); |
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break; |
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case GDL90_ID_TRANSPONDER_STATUS: |
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memcpy(&rx.decoded.transponder_status, msg.raw, sizeof(rx.decoded.transponder_status)); |
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if (rx.decoded.transponder_status.identActive) { |
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_frontend.out_state.tx_status.state |= UAVIONIX_ADSB_OUT_STATUS_STATE_IDENT_ACTIVE; |
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} else { |
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_frontend.out_state.tx_status.state &= ~UAVIONIX_ADSB_OUT_STATUS_STATE_IDENT_ACTIVE; |
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} |
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if (rx.decoded.transponder_status.modeAEnabled) { |
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_frontend.out_state.tx_status.state |= UAVIONIX_ADSB_OUT_STATUS_STATE_MODE_A_ENABLED; |
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} else { |
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_frontend.out_state.tx_status.state &= ~UAVIONIX_ADSB_OUT_STATUS_STATE_MODE_A_ENABLED; |
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} |
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if (rx.decoded.transponder_status.modeCEnabled) { |
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_frontend.out_state.tx_status.state |= UAVIONIX_ADSB_OUT_STATUS_STATE_MODE_C_ENABLED; |
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} else { |
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_frontend.out_state.tx_status.state &= ~UAVIONIX_ADSB_OUT_STATUS_STATE_MODE_C_ENABLED; |
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} |
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if (rx.decoded.transponder_status.modeSEnabled) { |
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_frontend.out_state.tx_status.state |= UAVIONIX_ADSB_OUT_STATUS_STATE_MODE_S_ENABLED; |
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} else { |
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_frontend.out_state.tx_status.state &= ~UAVIONIX_ADSB_OUT_STATUS_STATE_MODE_S_ENABLED; |
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} |
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if (rx.decoded.transponder_status.es1090TxEnabled) { |
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_frontend.out_state.tx_status.state |= UAVIONIX_ADSB_OUT_STATUS_STATE_1090ES_TX_ENABLED; |
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} else { |
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_frontend.out_state.tx_status.state &= ~UAVIONIX_ADSB_OUT_STATUS_STATE_1090ES_TX_ENABLED; |
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} |
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if (rx.decoded.transponder_status.x_bit) { |
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_frontend.out_state.tx_status.state |= UAVIONIX_ADSB_OUT_STATUS_STATE_XBIT_ENABLED; |
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} else { |
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_frontend.out_state.tx_status.state &= ~UAVIONIX_ADSB_OUT_STATUS_STATE_XBIT_ENABLED; |
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} |
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_frontend.out_state.tx_status.squawk = rx.decoded.transponder_status.squawkCode; |
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_frontend.out_state.tx_status.fault &= ~UAVIONIX_ADSB_OUT_STATUS_FAULT_STATUS_MESSAGE_UNAVAIL; |
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if (run_state.last_packet_Transponder_Status_ms == 0) { |
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// set initial control message contents to transponder defaults |
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_frontend.out_state.ctrl.modeAEnabled = rx.decoded.transponder_status.modeAEnabled; |
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_frontend.out_state.ctrl.modeCEnabled = rx.decoded.transponder_status.modeCEnabled; |
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_frontend.out_state.ctrl.modeSEnabled = rx.decoded.transponder_status.modeSEnabled; |
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_frontend.out_state.ctrl.es1090TxEnabled = rx.decoded.transponder_status.es1090TxEnabled; |
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_frontend.out_state.ctrl.squawkCode = rx.decoded.transponder_status.squawkCode; |
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_frontend.out_state.ctrl.x_bit = rx.decoded.transponder_status.x_bit; |
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} |
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run_state.last_packet_Transponder_Status_ms = AP_HAL::millis(); |
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gcs().send_message(MSG_UAVIONIX_ADSB_OUT_STATUS); |
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break; |
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#endif // AP_ADSB_UAVIONIX_UCP_CAPTURE_ALL_RX_PACKETS |
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case GDL90_ID_TRANSPONDER_CONTROL: |
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case GDL90_ID_GPS_DATA: |
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case GDL90_ID_MESSAGE_REQUEST: |
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// not handled, outbound only |
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break; |
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default: |
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//GCS_SEND_TEXT(MAV_SEVERITY_DEBUG,"ADSB:Unknown msg %d", (int)msg.messageId); |
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break; |
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} |
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} |
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const char* AP_ADSB_uAvionix_UCP::get_hardware_name(const uint8_t hwId) |
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{ |
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switch(hwId) { |
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case 0x09: return "Ping200s"; |
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case 0x0A: return "Ping20s"; |
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case 0x18: return "Ping200C"; |
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case 0x27: return "Ping20Z"; |
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case 0x2D: return "SkyBeaconX"; // (certified) |
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case 0x26: //return "Ping200Z/Ping200X"; // (uncertified). Let's fallthrough and use Ping200X |
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case 0x2F: return "Ping200X"; // (certified) |
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case 0x30: return "TailBeaconX"; // (certified) |
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} // switch hwId |
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return "Unknown HW"; |
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} |
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void AP_ADSB_uAvionix_UCP::send_Transponder_Control() |
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{ |
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GDL90_TRANSPONDER_CONTROL_MSG msg {}; |
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msg.messageId = GDL90_ID_TRANSPONDER_CONTROL; |
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msg.version = GDL90_TRANSPONDER_CONTROL_VERSION; |
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#if CONFIG_HAL_BOARD == HAL_BOARD_SITL |
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// when using the simulator, always declare we're on the ground to help |
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// inhibit chaos if this ias actually being broadcasted on real hardware |
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msg.airGroundState = ADSB_ON_GROUND; |
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#elif AP_ADSB_UAVIONIX_DETECT_GROUNDSTATE |
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msg.airGroundState = _frontend.out_state.is_flying ? ADSB_AIRBORNE_SUBSONIC : ADSB_ON_GROUND; |
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#else |
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msg.airGroundState = ADSB_AIRBORNE_SUBSONIC; |
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#endif |
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msg.baroCrossChecked = ADSB_NIC_BARO_UNVERIFIED; |
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msg.identActive = _frontend.out_state.ctrl.identActive; |
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_frontend.out_state.ctrl.identActive = false; // only send identButtonActive once per request |
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msg.modeAEnabled = _frontend.out_state.ctrl.modeAEnabled; |
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msg.modeCEnabled = _frontend.out_state.ctrl.modeCEnabled; |
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msg.modeSEnabled = _frontend.out_state.ctrl.modeSEnabled; |
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msg.es1090TxEnabled = _frontend.out_state.ctrl.es1090TxEnabled; |
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// if enabled via param ADSB_OPTIONS, use squawk 7400 while in any Loss-Comms related failsafe |
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// https://www.faa.gov/documentLibrary/media/Notice/N_JO_7110.724_5-2-9_UAS_Lost_Link_2.pdf |
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const AP_Notify& notify = AP::notify(); |
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if (((_frontend._options & uint32_t(AP_ADSB::AdsbOption::Squawk_7400_FS_RC)) && notify.flags.failsafe_radio) || |
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((_frontend._options & uint32_t(AP_ADSB::AdsbOption::Squawk_7400_FS_GCS)) && notify.flags.failsafe_gcs)) { |
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msg.squawkCode = 7400; |
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} else { |
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msg.squawkCode = _frontend.out_state.ctrl.squawkCode; |
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} |
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#if AP_ADSB_UAVIONIX_EMERGENCY_STATUS_ON_LOST_LINK |
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const uint32_t last_gcs_ms = gcs().sysid_myggcs_last_seen_time_ms(); |
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const bool gcs_lost_comms = (last_gcs_ms != 0) && (AP_HAL::millis() - last_gcs_ms > AP_ADSB_UAVIONIX_GCS_LOST_COMMS_LONG_TIMEOUT_MS); |
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msg.emergencyState = gcs_lost_comms ? ADSB_EMERGENCY_STATUS::ADSB_EMERGENCY_UAS_LOST_LINK : ADSB_EMERGENCY_STATUS::ADSB_EMERGENCY_NONE; |
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#else |
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msg.emergencyState = ADSB_EMERGENCY_STATUS::ADSB_EMERGENCY_NONE; |
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#endif |
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#if GDL90_TRANSPONDER_CONTROL_VERSION == 2 |
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msg.x_bit = 0; |
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#endif |
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memcpy(msg.callsign, _frontend.out_state.ctrl.callsign, sizeof(msg.callsign)); |
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gdl90Transmit((GDL90_TX_MESSAGE&)msg, sizeof(msg)); |
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} |
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void AP_ADSB_uAvionix_UCP::send_GPS_Data() |
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{ |
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GDL90_GPS_DATA_V2 msg {}; |
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msg.messageId = GDL90_ID_GPS_DATA; |
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msg.version = 2; |
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const AP_GPS &gps = AP::gps(); |
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const GPS_FIX fix = (GPS_FIX)gps.status(); |
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const bool fix_is_good = (fix >= GPS_FIX_3D); |
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const Vector3f velocity = fix_is_good ? gps.velocity() : Vector3f(); |
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msg.utcTime_s = gps.time_epoch_usec() * 1E-6; |
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msg.latitude_ddE7 = fix_is_good ? _frontend._my_loc.lat : INT32_MAX; |
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msg.longitude_ddE7 = fix_is_good ? _frontend._my_loc.lng : INT32_MAX; |
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msg.altitudeGnss_mm = fix_is_good ? (_frontend._my_loc.alt * 10): INT32_MAX; |
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// Protection Limits. FD or SBAS-based depending on state bits |
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msg.HPL_mm = UINT32_MAX; |
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msg.VPL_cm = UINT32_MAX; |
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// Figure of Merits |
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float accHoriz; |
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msg.horizontalFOM_mm = gps.horizontal_accuracy(accHoriz) ? accHoriz * 1E3 : UINT32_MAX; |
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float accVert; |
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msg.verticalFOM_cm = gps.vertical_accuracy(accVert) ? accVert * 1E2 : UINT16_MAX; |
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float accVel; |
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msg.horizontalVelocityFOM_mmps = gps.speed_accuracy(accVel) ? accVel * 1E3 : UINT16_MAX; |
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msg.verticalVelocityFOM_mmps = msg.horizontalVelocityFOM_mmps; |
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// Velocities |
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msg.verticalVelocity_cmps = fix_is_good ? -1.0f * velocity.z * 1E2 : INT16_MAX; |
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msg.northVelocity_mmps = fix_is_good ? velocity.x * 1E3 : INT32_MAX; |
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msg.eastVelocity_mmps = fix_is_good ? velocity.y * 1E3 : INT32_MAX; |
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// State |
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msg.fixType = fix; |
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GDL90_GPS_NAV_STATE nav_state {}; |
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nav_state.HPLfdeActive = 1; |
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nav_state.fault = 0; |
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nav_state.HrdMagNorth = 0; // 1 means "north" is magnetic north |
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msg.navState = nav_state; |
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msg.satsUsed = AP::gps().num_sats(); |
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gdl90Transmit((GDL90_TX_MESSAGE&)msg, sizeof(msg)); |
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} |
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bool AP_ADSB_uAvionix_UCP::hostTransmit(uint8_t *buffer, uint16_t length) |
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{ |
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if (_port == nullptr || _port->txspace() < length) { |
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return false; |
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} |
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_port->write(buffer, length); |
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return true; |
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} |
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bool AP_ADSB_uAvionix_UCP::request_msg(const GDL90_MESSAGE_ID msg_id) |
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{ |
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const GDL90_TRANSPONDER_MESSAGE_REQUEST_V2 msg = { |
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messageId : GDL90_ID_MESSAGE_REQUEST, |
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version : 2, |
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reqMsgId : msg_id |
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}; |
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return gdl90Transmit((GDL90_TX_MESSAGE&)msg, sizeof(msg)) != 0; |
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} |
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uint16_t AP_ADSB_uAvionix_UCP::gdl90Transmit(GDL90_TX_MESSAGE &message, const uint16_t length) |
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{ |
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uint8_t gdl90FrameBuffer[GDL90_TX_MAX_FRAME_LENGTH] {}; |
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|
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const uint16_t frameCrc = crc16_ccitt_GDL90((uint8_t*)&message.raw, length, 0); |
|
|
|
// Set flag byte in frame buffer |
|
gdl90FrameBuffer[0] = GDL90_FLAG_BYTE; |
|
uint16_t frameIndex = 1; |
|
|
|
// Copy and stuff all payload bytes into frame buffer |
|
for (uint16_t i = 0; i < length+2; i++) { |
|
// Check for overflow of frame buffer |
|
if (frameIndex >= GDL90_TX_MAX_FRAME_LENGTH) { |
|
return 0; |
|
} |
|
|
|
uint8_t data; |
|
// Append CRC to payload |
|
if (i == length) { |
|
data = LOWBYTE(frameCrc); |
|
} else if (i == length+1) { |
|
data = HIGHBYTE(frameCrc); |
|
} else { |
|
data = message.raw[i]; |
|
} |
|
|
|
if (data == GDL90_FLAG_BYTE || data == GDL90_CONTROL_ESCAPE_BYTE) { |
|
// Check for frame buffer overflow on stuffed byte |
|
if (frameIndex + 2 > GDL90_TX_MAX_FRAME_LENGTH) { |
|
return 0; |
|
} |
|
|
|
// Set control break and stuff this byte |
|
gdl90FrameBuffer[frameIndex++] = GDL90_CONTROL_ESCAPE_BYTE; |
|
gdl90FrameBuffer[frameIndex++] = data ^ GDL90_STUFF_BYTE; |
|
} else { |
|
gdl90FrameBuffer[frameIndex++] = data; |
|
} |
|
} |
|
|
|
// Add end of frame indication |
|
gdl90FrameBuffer[frameIndex++] = GDL90_FLAG_BYTE; |
|
|
|
// Push packet to UART |
|
if (hostTransmit(gdl90FrameBuffer, frameIndex)) { |
|
return frameIndex; |
|
} |
|
|
|
return 0; |
|
} |
|
|
|
|
|
bool AP_ADSB_uAvionix_UCP::parseByte(const uint8_t data, GDL90_RX_MESSAGE &msg, GDL90_RX_STATUS &status) |
|
{ |
|
switch (status.state) |
|
{ |
|
case GDL90_RX_IDLE: |
|
if (data == GDL90_FLAG_BYTE && status.prev_data == GDL90_FLAG_BYTE) { |
|
status.length = 0; |
|
status.state = GDL90_RX_IN_PACKET; |
|
} |
|
break; |
|
|
|
case GDL90_RX_IN_PACKET: |
|
if (data == GDL90_CONTROL_ESCAPE_BYTE) { |
|
status.state = GDL90_RX_UNSTUFF; |
|
|
|
} else if (data == GDL90_FLAG_BYTE) { |
|
// packet complete! Check CRC and restart packet cycle on all pass or fail scenarios |
|
status.state = GDL90_RX_IDLE; |
|
|
|
if (status.length < GDL90_OVERHEAD_LENGTH) { |
|
// something is wrong, there's no actual data |
|
return false; |
|
} |
|
|
|
const uint8_t crc_LSB = msg.raw[status.length - 2]; |
|
const uint8_t crc_MSB = msg.raw[status.length - 1]; |
|
|
|
// NOTE: status.length contains messageId, payload and CRC16. So status.length-3 is effective payload length |
|
msg.crc = (uint16_t)crc_LSB | ((uint16_t)crc_MSB << 8); |
|
const uint16_t crc = crc16_ccitt_GDL90((uint8_t*)&msg.raw, status.length-2, 0); |
|
if (crc == msg.crc) { |
|
status.prev_data = data; |
|
// NOTE: this is the only path that returns true |
|
return true; |
|
} |
|
|
|
} else if (status.length < GDL90_RX_MAX_PACKET_LENGTH) { |
|
msg.raw[status.length++] = data; |
|
|
|
} else { |
|
status.state = GDL90_RX_IDLE; |
|
} |
|
break; |
|
|
|
case GDL90_RX_UNSTUFF: |
|
msg.raw[status.length++] = data ^ GDL90_STUFF_BYTE; |
|
status.state = GDL90_RX_IN_PACKET; |
|
break; |
|
} |
|
status.prev_data = data; |
|
return false; |
|
} |
|
|
|
#endif // HAL_ADSB_UCP_ENABLED |
|
|
|
|