TBS Crossfire Manual
CRSf
CRSF is a protocol designed by Team BlackSheep and championed through the TBS Crossfire remote
control system. It has been integrated into most popular remote controls, is an incredibly high bandwidth
(low latency) full duplex, serial data transmission protocol. It comes with native functionality such as OTA
(over the air) firmware upgrades, localized configuration menus and a smart routing protocol.
CRSF can be selected on multiple outputs at the same time to connect several devices at once
Serial
The bridge feature gives you the ability to pass any kind of serial uart data from any device connected to
the receiver to any device connected to the transmitter. If you selected “Bridge TX” on a capable pin the
following pin will be set to “Bridge Rx” and the following to “Bridge RTS” (if not used by any other Serial
protocol). Please connect your device according to this information. The baud rate is set to 57600 8N1 and
the voltage level is 3.3V only. The RTS pin will change to logical high when the internal FIFO is almost full
and low if the FIFO is almost empty. There is no hardware flow control for the uplink as the wireless close
range telemetry module does not support it.
SBUS
SBus is the signal that is used by FrSky and other brands. The signal is inverted, which means on a F4 FC
you need to use a pad with a built-in signal inverter. Those pads are mostly label with “SBus” on your FC
N.i. SBUS
Not inverted SBUS is the same as SBUS except that the signal is not inverted. This can be used for FCs that
have no signal inverter built in and require SBus as input signal.
Receiver pin
Output type Micro V2/ Nano rx
Default value
1
PWM Ch1 to 12, PPM, RSSI, LQ, RSSI/LQ, SBUS, n.i. SBUS,
CRSF TX, MAVLink TX, SmartAudio, DSMX
CRSF TX
2
PWM Ch1 to 12, PPM, RSSI, LQ, RSSI/LQ, CRSF RX,
MAVLink RX
CRSF RX
3
PWM Ch1 to 12, PPM, RSSI, LQ, RSSI/LQ, CRSF RX,
MAVLink RX
PWM Ch. 3
4
PWM Ch1 to 12, PPM, RSSI, LQ, RSSI/LQ, SBUS, n.i. SBUS,
CRSF TX, MAVLink TX, SmartAudio, DSMX
Smart Audio
5 (BST)
PWM Ch1 to 12, RSSI, LQ, RSSI/LQ, BST SDA
BST SDA
6 (BST)
PWM Ch1 to 12, RSSI, LQ, RSSI/LQ, BST SCL
BST SCL
41