PixHawk4 mini - RC in or PPM

Mauro_Gatti · July 1, 2020, 11:13am

Hi guys, i need a clarification about how to right connect receiver to Pixhawk4 mini. I have an Holybro QAV250 development kit and R-XSR (access protocol) in sbus. I have connected it to RC IN port (via sbus) but sems that QAV not respond in the right way to trasmitter input (roll, yaw, …) . I read in

github.com

ArduPilot/ardupilot/blob/master/libraries/AP_HAL_ChibiOS/hwdef/PH4-mini/README.md

# Pixhawk4-Mini Flight Controller

The Pixhawk4-Mini flight controller is sold by [Holybro](http://www.holybro.com/product/64)

## Features

 - STM32F765 microcontroller
 - Two IMUs: ICM20689 and BMI055
 - MS5611 SPI barometer
 - builtin I2C IST8310 magnetometer
 - microSD card slot
 - 5 UARTs plus USB
 - 8 PWM outputs
 - Two I2C and one CAN ports
 - External Buzzer
 - external safety Switch
 - dedicated power input port for external power bricks

## Pinout

This file has been truncated. show original

that RC IN should not be used to connect receiver but only PPM port that should support also SBUS.

I load ardupilot stack 4.03 latest.

Which is the correct reciver installation? Because there are some conflicting info !

manavgandhi17 · July 1, 2020, 8:38pm

I use PPM on my Pixhawk 4 Mini without any problems.

pjtpdx · June 8, 2021, 5:33pm

@Mauro_Gatti,
Did you solve the problem? I have the same issue. I’ve tried the supplied XSR cable, and the PPM cable and still get “0 radio channels” from both ArduPilot and QGC.
-P

EDIT: Turns out the R-XSR to PPM cable I was using had the yellow wire connected to S.Port (since it is used to connect to the Transmitter for firmware updating), rather than SBUS-OUT. I moved the yellow wire over one pin (there’s only one way to go, since the other way is VCC) and now it works.

Mauro_Gatti · June 9, 2021, 6:31am

Hi Peter, i have solved the receiver issue on my Pix4min FC. The issue was related to PPM that is not correctly supported and it is better use S-Bus. So i will send soon some picture in order to show my wiring.

dazonic · April 7, 2022, 11:27am

Any chance you have a pic or diagram of the wiring? I’ve got a PH4 mini and R-XSR but can’t get Mission Planner to see transmitter inputs. I’m following the docs to use SBUS but I think my wiring is wrong

Mauro_Gatti · April 7, 2022, 1:08pm

Dear Darren. For sure. Keep in touch. I’m far from my home now ;).

dazonic · April 8, 2022, 3:05am

No worries. I’m also interested in your SERIAL4 params. I’d ultimately like telemetry as well and I’m not sure if I need more hardware to achieve this. Thanks.

xfacta · April 8, 2022, 4:26am

You have a wiring error.
The yellow wire needs to be connected to the SBUS OUT/CPPM pin of the receiver.
The blue S.Port wire at the Pixhawk end needs to be either disconnected entirely, or go to a serial port (possibly via a converter) for sending telemetry data from the Pixhawk to the reciever and on to the transmitter for use in Yaapu telemetry script.

Mauro_Gatti · April 8, 2022, 6:16pm

Dear @dazonic ,
i confirm the suggestion of @xfacta .
You have to reverse fisically the cable and connect SBUS OUT/CPPM pin of the receiver.
Below the picture of my wire installation.

dazonic · April 9, 2022, 11:39am

Awesome. Thanks legends. Works now with:

SERIAL4_OPTIONS 8
SERIAL4_PROTOCOL 23

@Mauro_Gatti do you have telemetry set up?