Plane 4.0 release

[kd0aij (Mark Whitehorn)]

Some F4 boards have external inverters; the PixRacer has one for UART8, but the MatekF405 has none. But the F7 processor has built-in support for inversion of all uarts.

I use an inverter cable with my F405-Wing:

E-flite Convergence Using Matek F405 Wing

Thanks @davidabevan, I can’t see those LEDs with the hatch cover on anyway I just re-maidened my Convergence after swapping the Pixracer for an F405-Wing. QSTABILIZE, QHOVER and QLOITER looked OK. (this is with the pr-man-fwd-thr binary I posted on Gdrive) I had a lot of difficulty in getting the parameter values straightened out… After finally getting the compass working and the servos trimmed, I found on the first hover that I had the yaw oscillation noted by @hwurzburg. Tu…