Thanks @modaltb , that worked! I had to set it to run as a background function using the &. It's running perfectly now.

I probably want to rewrite it as a task, but that example code looked tough to follow. I wish the PX4 developer manual included more step by step tutorials, like the ROS tutorials.

When doing firmware development or basic Flight Core setup with QGroundControl such as loading custom firmware I prefer to not need the Power Module. Unfortunately the USB connector on the Flight Core does not pass through the +5V so the board can't be powered by USB alone.

To fix this issue I hack into the provided USB cable and attach a second 4-pin connector to the +5V and Gnd wires that then can provide USB power to the CAN connector J8. See photos.

This is not ideal, but it gets the job done. I've asked Modal AI to consider making this cable themselves to sell or provide with the Flight Core kit.

I'm sure the concern is browning out the +5V from the USB.

When doing firmware development or basic Flight Core setup with QGroundControl such as loading custom firmware I prefer to not need the Power Module. Unfortunately the USB connector on the Flight Core does not pass through the +5V so the board can't be powered by USB alone.

To fix this issue I hack into the provided USB cable and attach a second 4-pin connector to the +5V and Gnd wires that then can provide USB power to the CAN connector J8. See photos.

This is not ideal, but it gets the job done. I've asked Modal AI to consider making this cable themselves to sell or provide with the Flight Core kit.

I'm sure the concern is browning out the +5V from the USB.

Ah, when I run the PWM program there is no chatter on the PWM signals, so I'm going to review that code again and compare it to mine.

I don't have a pwm_out driver. I do have a pwm_servo, and it's being called from PX4FMU, such as from update_pwm_out_state.

What I need to do, I think, is disable the mixer values for PWM so that I can set them manually. I'm not sure if my

ret = px4_ioctl(fd, PWM_SERVO_SET(PORT_FIN), pwm_value);

command goes to the mixer, or if I can bypass the mixer in mixer_module.cpp.

I'm basically commenting out things one at a time to see what happens since I'm not set up to step through the code.

@modaltb Can you help point me to where PWM is being enabled once EKF2 is initialized? I can't seem to get rid of this chatter.

That worked, and now I'm getting pitch from vehicle_attitude.
With the filter enabled though, PWM is also being enabled by the system, which is interfering with the code I wrote to manually control them. I'm getting chattering.

I branched off of version 1.0.

Just the flight controller, and honestly not really even that. Just the sensors. There is no vision. I will connect my compass and calibrate it and see if that does the trick. I'm on the bench so rotating the compass isn't always easy.

Is there a parameter I need, or a minimum number of sensors, to produce a vehicle_attitude message? I'm looking for a clean pitch/roll/yaw but it's not being published. I don't have a GPS/compass plugged in at the moment, but my gyros and IMU are calibrated.

Good question. These servos don't specify the logic power so I'll have to measure it.
I'm not seeing 5V at all though on the PWM breakout board. It should be the middle set of pins, correct?

Do you know why the 5V on the J7 PWM connector is for "reference only"? If I need to provide 5V to my PWM logic on the center rail of the 8-channel breakout, then I need to cut into the cable? Or I suppose I can provide 5V power on one of the other channels since I'm currently only using 4 of them, but now I need to find 5V from somewhere.

Has anyone been able to program the board via RF? It's generally not advisable, I know. I was just hoping to expedite hardware testing with the board inside a pressure vessel. I tried with the PX4 build tools, Mission Planner, and QGroundControl and none of them seemed to find the board through the radio after the power cycle.