USB adapter for Sega Mega Drive gamepads

Article on habr.com: https://habr.com/p/900300/

SegaGamepad library:
https://github.com/IvoryRubble/ArduinoSegaGamepadLibrary
https://registry.platformio.org/libraries/ivoryrubble/SegaGamepad

Adapter features:

• Supports two gamepads
• No gamepads modification needed
• Supports both 3-buttons and 6-buttons gamepads
• Recognized by PC as USB keyboard or two USB gamepads (working mode can be switched any time)

Video demo:
https://youtu.be/ejnmY7F8hcU
https://youtu.be/ySdsnPrBBsU
https://vkvideo.ru/video-228936534_456239017
https://vkvideo.ru/video-228936534_456239020

SegaGamepad library

Yet another library to read Sega Mega Drive (aka Sega Genesis) gamepad.
Supports both three and six buttons controllers.

Sources

Gamepad protocol description:
http://web.archive.org/web/20171229105419/http://www.cs.cmu.edu/~chuck/infopg/segasix.txt
https://github.com/jonthysell/SegaController/wiki/How-To-Read-Sega-Controllers

Gamepad protocol reverse engineering:
https://www.raspberryfield.life/2019/03/25/sega-mega-drive-genesis-6-button-xyz-controller/#SMD6-protocol-overview

Another good library:
https://github.com/jonthysell/SegaController

Pinout

Sega Mega Drive gamepad connector pinout, female DB9 plug:

   +----------- pin5, +5V
   | +--------- pin4, set by gamepad            
   | | +------- pin3, set by gamepad  
   | | | +----- pin2, set by gamepad   
   | | | | +--- pin1, set by gamepad
   | | | | |            
+-------------+             
 \ O O O O O /                
  \ O O O O /                  
   +-------+                 
    | | | |
    | | | +---- pin6, set by gamepad
    | | +------ pin7, Select pin, set to 0 or 1 by microcontroller        
    | +-------- pin8, GND
    +---------- pin9, set by gamepad         

Connection

Connect pin8 and pin5 to GND and +5V.
Connect pin1, pin2, pin3, pin4, pin6, pin7, pin9 to microcontroller I/O pins.

Usage

Set correcponding pin1, pin2, pin3, pin4, pin6, pin7, pin9 numbers in SegaGamepad::SegaGamepad() constructor.
Optionally set custom delayBeforeReadMicros and delayBeforeNextUpdateMicros delays.
Example:

SegaGamepad segaGamepad(1, 2, 3, 4, 5, 6, 7);

Call SegaGamepad::init() method in setup() procedure to initialize microcontroller ports for gamepad.
Example:

segaGamepad.init(); 

Call SegaGamepad::update() method to read new values from controller.
Then you can keys get values from segaGamepad object fields. True value means corresponding key is pressed.
You also can check if controller is connected by reading isConnected flag.
And you can check type of controller (three or six buttons) by reading isSixBtns flag.
When controller is not connected then isConnected flag is set to False, all buttons values are set to False, is isSixBtns flag is set to False.
Example:

segaGamepad.update();
Serial.println(segaGamepad.isConnected);
Serial.println(segaGamepad.btnUp);
Serial.println(segaGamepad.btnA);
Serial.println(segaGamepad.btnStart);

Some photos