Hi all,

I've been brainstorming with Serge from Serdaco about a possible new product for Serdaco, which would enable the use of
digital (eg ATARI style) joysticks such as 1 fire-button ATARI 2600 and Commodore 64 joysticks, 2 fire-button SEGA Master System gamepads and more advanced gamepads such as the SEGA Genesis gamepad with a D-PAD, start button and 6 "fire" buttons, through the PCs RS-232 DB9 port, and through keyboard emulation, can be configured to play any DOS game that uses keys on the keyboard for gameplay controls.
RS-232 is better than for example parallel as it's fast enough for this kind of device, and you'll want to keep the parallel port free for an OPL3LPT or S2P or similar parallel port sound-card.

This product will be aimed at retro gamers with retro laptops/palmtops/luggables and other MS-DOS PCs.

Here's a description of my idea:

A device the size of a ps2serial (https://www.serdashop.com/PS2TOSERIAL), with a DB-9 RS-232 port that connects to the PC,
and, instead of a PS/2 connector for the mouse, it has an ATARI style joystick connector (eg a 9 pin one, compatible with ATARI 2600, C64, Sega Genesis etc...)

The firmware on the device will read the gamepad's button states, and send standard key characters to the PC through the RS-232 port for the state of the gamepad's buttons, continuously.

On the PC, you load a TSR driver that implements the device, and, when loaded/active, can be configured with a separate command line tool,
so it can be configured to remap the button keys to a set of custom, user-defined keyboard keys, particular to your game you want to run.

The idea is that you write a dos batch file that first configures the TSR with the correct keys to use for the different buttons on the joystick or gamepad for your game,
and then launches your game, so you can play it with the gamepad instead of the keyboard.

There are a large amount of real and cloned SEGA genesis controllers available on e-bay and other sites, some cheap and crappy, and some a bit more expensive and of good quality,
and having up to 6 fire-buttons is definitely enough 😀

This way you can easily turn a vintage laptop/palmtop/luggable/PC into a proper retro DOS gaming machine by adding a genesis-like gamepad on the serial port,
and an OPL3LPT or S2P on the parallel port for audio/music, and you'll have the complete experience, with good and precise control by using the genesis controller instead of keys on your keyboard 😀

The product could be called the "serialpad" or something...

I wouldn't bother with traditional analog-style PC joystick ports, as you can't map analog values to keys, so it's better to use only use digital, eg on/off buttonned gamepads or joysticks,
like on the Atari 2600, C64, SEGA Master System and Genesis, and many more...

I also think that, to save development time, you can probably start with the PCB of a ps2serial, and make changes to it,
just changing the PS/2 port to an Atari-style joystick port, and of course changing the current ps2serial mouse firmware for the microcontroller on it to firmware
that does the joystick button translation.

Me and Serge would love to hear your comments and what you think of a device like this being available,
and if you would be interested in getting one should it get developed / produced and sold in the future...

Thanks for your time!,
Yours,
Terrence