SNEStoMDjoy

Super Famicom/Super Nintendo/SNES controller to Megadrive/Genesis converter. Using Arduino Nano (Atmega328p).
Holding down Select button at the startup enables 3-button mode.

SNES controller pinout:

 ______________________________________
|                     |                 \
| (1)  (2)  (3)  (4)  |  (5)  (6)  (7)   )
|_____________________|________________ /

Pin	Function	Wire color
1	+5V	White
2	Clock	Yellow
3	Latch	Orange
4	Data	Red
5	-	no wire
6	-	no wire
7	Gnd	Brown

Connection to MCU:

SNES	Atmega Pin
2 (Clock)	PC0
3 (Latch)	PC1
4 (Data)	PC2

Mega Drive controller pinout (front of console):

 ___________________________
\                           /
 \   (1) (2) (3) (4) (5)   /
  \    (6) (7) (8) (9)    /
   \ ___________________ /

Pin	Function	Wire color
1	Up	Brown
2	Down	Red
3	Left	Orange
4	Right	Yellow
5	+5V	Green
6	A/B	Blue
7	Select	Grey
8	GND	Black
9	Start/C	White

Connection to MCU:

MD	Atmega Pin
1 (Up)	PD2
2 (Down)	PD3
3 (Left)	PD4
4 (Right)	PD5
6 (A/B)	PD6
7 (Select)	PB0
9 (Start/C)	PD7