SerialRX like SpekSat, Futaba SBUS, Graupner SUMD

Cesco1 edited this page Jan 31, 2015 · 17 revisions


SerialRX is a purely digital lossless protocol that uses 3 wires, signal, power, ground. Serialrx does use a serial port on the Naze32, means no other devices like GPS can be connected unless you use feature softserial. SerialRX is not like PPMSUM which is still analog in time domain.

To enable SerialRX use CLI and type:

feature SERIALRX

and then choose the type of receiver by typing one of the following lines

"set serialrx_type=0" for Spektrum 10bit (1024)
"set serialrx_type=1" for Spektrum 11bit (2048)
"set serialrx_type=2" for Futaba SBUS mode
"set serialrx_type=3" for Graupner SUMD
"set serialrx_type=4" for msp
"set serialrx_type=5" for Flysky IBUS


SpektSat connections are ground, input pin 4, 3.3V power (NOT 5V, use the 3.3V pin) See here where the 3.3V pin is Rev5 pdf

Or you use a 3.3V adapter cable 3.3V adapter cable

How to bind spektrum satellite to Tx without main Rx

  • Make sure that satellite has been connected correctly.
  • Connect Naze32 to USB
  • Open baseflight and connect to Naze32 (baseflight app in Chrome)
  • From Configuration tab make sure that you have selected "Enable Serial-based receiver" and Serial receiver is correct (e.g. SPEKTRM2048 for DSMX)
  • From CLI tab type: "set spektrum_sat_bind = 9" for DSMX or "set spektrum_sat_bind = 5" from DSM2
  • type "save" and after Naze32 reboot remove USB cable (=Power off the Naze32)
  • Wait a sec and reconnect the USB cable. After cold start satellite led should start blinking and transmitter should be turned on while pressing the bind button.
  • After binding satellite led should be solid. Connect baseflight and use receiver tab to test that satellite is working correctly.
  • Final step is to go to CLI tab and type "set spektrum_sat_bind = 0" and then type "save". This must be done so that satellite doesn't go back to binding mode when Naze32 is repowered again.


For SBUS you need a hardware signal inverter. Signal goes to input pin 4, power is 5V. Cheap SBUS inverter


SumD is the simplest, ground, input pin 4, 5V power. Set the receiver to SUMD with the transmitter.

Serial MSP

Multwii serial protocol rc commande. It will listen on the main serial port


IBUS is simple, ground, input pin 4, 5V power. Use the ibus "out" or ibus "servo" connector.

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