FBUS/S.Port Sensors¶
The FBUS/S.Port Sensors tab is a diagnostic and forwarding-control page for
boards acting as an FBUS or S.Port master -- reading telemetry directly
from third-party FrSky-ecosystem sensors (GPS, current sensors, RPM sensors,
smart servos, and more) wired to a spare UART, rather than talking to a
receiver on it. The tab only appears once a serial port is assigned the
FBUS_OUT or SPORT_MASTER function on the Configuration
tab.
Reading sensors: direct use vs. forwarding¶
Sensors observed on the bus can be put to work two different (non-exclusive) ways:
- Direct use -- the firmware reads certain sensor types itself and feeds
them straight into existing systems. A FrSky current/voltage sensor can
become a battery voltage/current source -- set Battery Voltage/Current
Source to FrSky Sensor on the Power tab. A FrSky ESC
sensor can become an ESC telemetry source (voltage, current, RPM,
temperature, consumption); this one is currently CLI-only --
set esc_sensor_protocol = FBUS. Nothing needs enabling on this page for direct use -- it happens automatically as soon as the sensor is observed. - Forwarding -- relays a sensor's raw telemetry frames back out over the receiver link, so your transmitter/radio displays them directly. This matters most for sensor types the firmware doesn't consume itself (a vario or airspeed sensor, for example) -- forwarding is the only way to see those values on the radio. The Forwarded toggle on this page controls it.
The sensor table¶
Each row is a sensor physical ID actually observed talking on the bus, refreshed roughly once a second:
| Column | Meaning |
|---|---|
| Physical ID | The sensor's hardware-defined identity (e.g. GPS, FLVSS, ESC) -- see the Sensor ID Reference for the full list |
| Source | Which physical bus it was seen on -- FBUS or S.Port |
| Sensor Name | Resolved sensor name, or ID_<n> if the physical ID isn't recognized |
| App IDs | The specific data types seen from this sensor (e.g. altitude, speed) -- see the reference page for what the numbers mean |
| Packets | Running packet count since the last connect or Clear |
| Forwarded | Whether this sensor is currently relayed back to the receiver -- see Forwarding below |
Clear resets the observed-sensor table and packet counts -- useful after rewiring, to confirm what's actually present now rather than what was seen earlier in the session. It doesn't affect Forwarding configuration.
Forwarding¶
Toggling Forwarded takes effect immediately -- no reboot needed -- and persists across power cycles. Up to 8 sensors can be forwarded at once; toggling a 9th while all 8 slots are in use is refused, so turn one off first.
The Forwarded toggle is only enabled when the receiver protocol itself is FrSky-family -- F.Port, F.Port2, or FBUS, set on the Receiver tab; otherwise it shows dimmed, and hovering it explains why. It works by relaying frames over that protocol's own telemetry return channel, which other protocols (CRSF, Ghost, and the rest) don't have. Reading sensors as a bus master, and using them directly, both work regardless of receiver protocol -- only forwarding to the radio needs FrSky-family.
Note
FBUS/S.Port master mode and the receiver's own RX protocol are independent: the master feature listens on its own dedicated UART, so it works alongside CRSF, ELRS, or any other receiver protocol. Only forwarding ties back to what the receiver link speaks.