Sega Genesis/MegaDrive gamepad to Commodore 64/128/VIC-20/Amiga joystick adapter

Description

Acknowledgement - This opensource item was designed by Sukko Pera.
Listed is a brand new joystick adapter for Sega Genesis / MegaDrive gamepad to Commodore 64/128/VIC-20/Amiga
(Rev 5 PCB)
If you have any questions about the assembly, feel free to contact me. I will help in anyway I can.
Check out this link to my video if you're curious how they are assembled.
https://youtu.be/Q4vblJy8u6o
TERMS
-
Sale is final. NO returns or refunds - That being said... I am a reasonable person... talk to me and I'll try to help if I can.
*Please read the description carefully before buying!
In this version the PCB has a particular shape making it
compatible with the Amiga 600
case. A manual cut of the DB9 connector is required in order to allow this adapter to fit into the A600 port 2. An extension cable is no longer required for use with the Amiga 600 if you make this modification.
This
version
uses
switches
instead of jumpers, this make the configuration much easier, plus now is impossible to set an improper configuration. Is still recommended to turn off the computer before change the configuration. The UP direction on the D-PAD is always active, it cannot be disabled. It can be used together with another button configured as UP. An extra diode (D6) is used to separate the two UP lines.
In the older versions of the adapter, sometimes the second button was not recognized by some games, now a transistor is used to fix this issue.
*Despite being compatible at the physical level (i.e.: they use the same DB-9 connectors), Sega Genesis / Mega Drive controllers are slightly different from the Atari-style joysticks (which the C64 uses) at the electrical level. These differences usually manifest themselves in the fact that certain keyboard keys are not responsive when a Sega Mega Drive pad is connected to a C64 computer, but the CIA chip may also get harmed as a result.
I personally think that the Sega Genesis / Mega Drive controller is one of the best joypads ever created.
This device sits in between the computer and the controller. You should be able to keep it plugged into the computer and then connect the controller to it. Button B will work as the normal fire button, but this adapter also allows using Button C as the second fire button, for those games that support two buttons.
While this all works out of the box on Amiga computers, this adapter also allows to customize the button mapping to a certain degree: for instance, replacing UP with C might make some games more comfortable to play. This might be useful on the Amiga as well, so the adapter also supports an Amiga mode.
In this version the D-PAD UP is always active, it ca be used in games as usual, this is handy for games witch use UP for multiple things: menu, jump, go upstairs, etc.
Configuration
The board is based on the circuit that was originally published in issue #5 of Commodore world back in 1994, with a few improvements that will allow an easier gameplay with certain titles.
First of all, be sure to move the C64/Amiga switch to the proper position, before connecting the adapter.
Since most joysticks back in the day only had a single fire button, it was usually used for firing, whatever that meant. Jumping was usually done with the UP direction of the joystick, which is quite annoying on a joypad. This is why OpenC64MegaDrivePadAdapter allows you to repurpose the B or C key to jumping, leaving the other button for firing, all at your choice. It also allows to use C as the second fire button, which is only supported by a few titles. You can even swap B and C, if you prefer.
The switches configurations are showed on a little table printed on the board. F1 and F2 on the table refers to FIRE1 and FIRE2 switches.
The FIRE1 switch select which button to use as FIRE 1, B or C.
The FIRE2 switch select which action the FIRE 2 button must perform, UP (the same of the D-PAD UP) or FIRE.
*ALWAYS TURN YOUR COMPUTER OFF BEFORE MOVING THE CONFIGURATION SWITCHES. If you don't follow this rule, you will probably cause permanent damage to your computer and/or controller, so please be careful, you have been warned.
I am not liable for damage to your computer, controller, adapter or any other items that might be damaged by human error or product failure.
Compatibility
This adapter is compatible with every Sega Genesis gamepad, even the 6 buttons one. And also with the Master System gamepad.
The Mega Drive gamepad is designed to be back compatible with the Master System. B and C on the Mega Drive are BUTTON 1 and BUTTON 2 on the Master System.
To add more buttons on the Mega Drive, SEGA added an extra line (SELECT) which is toggled HIGH or LOW. The state of this line determinate which set of buttons the pad must return (B and C or A and START). Since in this adapter the SELECT line is always HIGH, only the B and C buttons are used.
License
OpenC64MegaDrivePadAdapter is Open Hardware.