What are the four CAP pins on the PixHawk 4 Mini?

#1

Recently bought a QAV250 kit with a PixHawk 4 Mini as my first step into quad and autopilot. Expected to recycle an older Spektrum DX5e with an AR6110e reciever, at least until I learned enough to make a different RC purchase. As I looked to connect the AR6110e to the PX4, I see the error of my ways.

The AR6110e RCVR appears to have only PWM outputs (THRO, AILE, ELEV, RUDD, etc.) and the PicHawk 4 normally wants a single channel, (PPM?), from the RC.

I suspect my only choice to use AR6110e RCVR is to buy a PWM Encoder board, such as the “Hobbypower PPM Encoder V2.0”.

Question here is: What are the four CAP pins on the PixHawk 4 Mini? The docs https://docs.px4.io/en/flight_controller/pixhawk4_mini.html#interfaces
say they are “PWM Input Capture”. It would seem I could jumper four PWM outputs of the AR6110e to the four CAP “S” pins and get four channel control. (+: 5V and GNDs)

However, running through the QGroundControl V3.4.4 Vehicle Setups, I saw no reference to such a configuration.

Can CAP’s be used with existing software?