Pixhawk 4 PMB Servo Output

I’m working on getting the landing gear to work on the UAS team’s Tarot X6 and I think my problem is that I cannot figure out how to map the Landing Gear function to the first pin of FMU-PWM-out on the Power Management Board. My goal is to set the Landing Gear function up to any FMU-PWM-out pin that will let me control it via the Landing Gear channel.

I have Channel 8 (2-position switch) on the Spektrum DX8 set to landing gear under the Servo Output tab in Mission Planner’s Setup>Mandatory Hardware>Servo Output. Toggling Ch8 highlights and unhighlights the landing gear option.

I initially tried setting all ServoX options to 29 in hopes that it would cause some response with the landing gear, but that did nothing for me. If needed I have access to multi meter, oscilloscopes, power supplies. Does anyone here have their landing gear setup on their Pixhawk 4 PMB FMU-PWM Out that could please share how they’ve done it?


from what I remember helping someone else with the Pixhawk 4 / PM07, Ardupilot outputs 1-8 (IO PWM) are broken out through the solder pads M1-M8. FMU PWM pins on the PM-07 are Ardupilot outputs 9-16. So the first FMU PWM pin should be output 9, not 8. Also note that there is no power on the FMU PWM pins, you need to connect a BEC to power a servo.

Thanks a bunch. Servo9 function was just what I needed for that FMU PWM Out pin 1.