Hello everyone,
I am new to PX4 development but a part time contributor to other firmwares; in my learning of PX4 and applying PX4 to FPV-style architectures i saw that the built-in atxxxx driver had barely anything in it and had baked-in configurations that required a firmware build to change. I decided to tackle this on v1.17 on my MicoAir H743V2 board. After some struggling with issues due to bad SPI assignment; i managed to significantly improve and enrich it, adding a wide variety of elements that we expect from FPV-world firmwares; and making it fully QGC-configurable in bitmask activation and X/Y position.
Power
OSD_BAT_VOLT: main battery voltageOSD_CELL_V: average cell voltageOSD_MAH: consumed battery capacity in mAhOSD_CURRENT: current draw in A; andOSD_POWER: electrical power in W.
Radio link
OSD_RSSI: RSSI in dBm when available, otherwise the normalized RC or telemetry-radio RSSI value; andOSD_LQ: RC link quality.
GNSS and navigation
OSD_GPS_SAT: satellite countOSD_GPS_SPD: ground speed in km/hOSD_GPS_INFO: fix type, PDOP, and estimated horizontal position errorOSD_GPS_LAT: latitudeOSD_GPS_LON: longitudeOSD_ALT: local altitudeOSD_VARIO: numerical vertical speedOSD_HOME_DST: distance to homeOSD_HEAD: heading in degreesOSD_MISSION: mission state, including no mission, failure, warning, completion, and current/total sequence progress.
Vehicle and flight state
OSD_SYSID: system IDOSD_MAV_STATE: MAV state derived from initialization, standby, calibration, active, critical/failsafe, and termination stateOSD_MODE: flight modeOSD_ARM: armed/disarmed stateOSD_FTIME: elapsed armed flight timeOSD_THROT: throttle percentageOSD_PITCH: numerical pitchOSD_ROLL: numerical roll.
Warnings and status
OSD_STATUS: scrolling PX4 log messages and fallback vehicle status textOSD_LOG_LEVEL: minimum PX4 log-message severity displayedOSD_SCROLL_RATE: long-message scroll periodOSD_DWELL_TIME: pause at the beginning of a scrolling message.
The fallback status text covers missing vehicle status, failsafe, failure detector events, battery warning, RC loss, invalid attitude, invalid local position, invalid global position, missing home position, armed, ready, and not ready states.
Graphical overlays
OSD_AH: artificial horizon projected from vehicle pitch and rollOSD_CAM_HFOV: horizontal camera FOV used by the artificial-horizon projectionOSD_CAM_VFOV: vertical camera FOV used by the artificial-horizon projectionOSD_CAM_UPT: camera uptilt compensation used by the artificial-horizon projectionOSD_CROSS: separately positionable center crosshair.
VTX, when CONFIG_DRIVERS_VTX is enabled
OSD_VTX_INFO: band, channel, and power-level indexOSD_VTX_FREQ: frequency in MHzOSD_VTX_POWER: configured power label in mW
Some elements i haven’t had the chance to fully test and refine in detail, particularly the intended scrolling status and messages. It could still use some finer aesthetic/UI ajustments. Also, the default at7456 font lacks some glyphs usually found on other firmwares and is generally less refined. But it is working and usable.
It leverages some already existing code from MSP OSD and adapts some of it’s code as a common layer. I’ve verified it works with the OSD chip, but i do not have a video system that uses MSP OSD (ie: DJI) so testing would be appreciated from those who use it.
Master-based: GitHub - xznhj8129/PX4-Autopilot at improve-analog-osd · GitHub
Specific MicoAir H743V2 build: GitHub - xznhj8129/PX4-Autopilot at v1.17-micoair-h743v2-analog · GitHub
My specific 1.17 build backports the analog vtxtables module and changes some non-OSD things that were needed for compatibility with ELRS-Mavlink and the JHEMCU VTX; so it’s not universally applicable. Thisis the branch i’ve tested in flight.
I haven’t yet submitted a PR pending testing the master build and figuring out the procedure with regards to development; but i’m posting this here for everyone’s benefit.
