JoySaturn: Sega Saturn to MSX adapter

This is the male connector on the joystick:
Sega Saturn male connector on controller

The Sega Saturn joystick port is just a Sega Megadrive joystick port with a different connector. This happened because Atari sued Sega because of the DE-9 joystick connector.

In other words, a JoySaturn adapter is nothing more than a JoyMega adapter with a different connector. You can buy a cheap Sega Saturn extension cord on eBay and cut it in the middle to make the adapter.

Saturn pin	NC7ST04M5X pin	MSX pin	Pin name
1	5	5	Vcc
2		2	Down
3		1	Up
4	2	-	TH
-	4	8	Output
5		7	TR/TRG2
6		6	TL/TRG1
7		4	Right
8		3	Left
9	3	9	GND

Note: Sega Saturn controllers have a different protocol and won't be recognized by standard MSX software or BIOS. They need specific software support that is available on the MSX HIDlib. The MK80117 analog "3D controller" protocol is described at this page.