Tonight I wrote some code and tested it on my Harmony Cart for my Hypothetical Controller concept, which will be implemented as a controller option for the Mr.Boehm.

Below is a photo of my breadboard prototype.

The fire buttons (Pins 6, 3, 2, 1 connected to ground through push button switches) worked just fine interfacing with the Harmony Cart GUI, which is not surprising. While I haven't implemented them yet in my Test Rom, I doubt it will be much of an issue.

I tested the paddle driven HAT (Pins 5 & 9 connected to Pin 7 power through resistors and push buttons) in a ROM created on 8Bit Workshop.

Right and Down each connect to Pin 7 through a push buttons. Left and Up each connect to Pin 7 power through a 200K resistor and a push button. I tried using 470K resistors, but it was too much for my code to recognize. Maybe if I had scanned one or two scanlines later it would have worked.

The disk is the sticky part of a broken pop socket.

On scanline zero I measure for instantaneous capacitor discharge for all paddle capacitors. On scanline 189 I measure a 2nd time. Each time capacitor discharge is released, a variable gets incremented by 1. So a variable value of 2 means that the right/down buttons are pressed. A value of 1 means the left/up buttons are pressed, and a value of 0 means centered for that axis.

Also part of the prototype is a vibrating motor connected to Pin 4 and Pin 8 ground, with pin 4 set to output. I haven't tested this feature yet, so not sure if it works.

Anyway, the paddle-driven directional hat worked on both 7800 ports. I was able to move both player missiles around the screen as if I was controlling each with a standard joystick.

Once I get the code cleaned up and add in Rumble support in the ROM, I will post code and video of it in action.