Discrete input joystick to Atari 7800 and 2600 Booster Grip adapter

I know these systems have direct discrete plug ins: the basic Atari 2600, Astrocade, Sega Master System, and Neo Geo. Most other systems, even as early as the Intellivision and Colecovision, have coded signals, that need computer intelligence in a PCB to read right. Edladdin has a Discrete-> Colecovision solution. For Intellivision, one guy said he’s making a Genesis->INTV and a Jaguar -> INTV solution.

The 2 “iffy systems” are the 7800 and the 2600 booster grip. Someone who understands electronics knows it’s not iffy, but with the amount of knowledge I displayed (which is basic) it might seem so.

The 7800 has 2 DB9 pins wired to each of the 2 buttons, two individual button pins, and one pin wired to both buttons. Is it as simple as y-ing or double connecting the wires, or do you need some sort of “OR circuit” for that common pin? If it’s a simple as #1, should any joystick builder be able to do it easily?

Each button has a unique pin on the 2600 booster grip. But 2 of the buttons are on pins reserved for analog inputs. Is the only difference between a digital signal and an analog one is that the “dimmer switch”, which is basically a paddle, is removed, and gets actuated at maximum signal, and becomes a simple on/off switch? [Pardon me for not knowing the exact electrical jargon.] If it is, then it should be easy to make a discrete->discrete adapter.

I know I could buy a Edladdin Genesis->7800 adapter, but would rather have a direct adapter for quicker delay time than processing through a Genesis->7800 PCB, and may be cheaper assuming you start with a discrete joystick if my joystick maker charges $2 a two-way pin connection.