SEGA Genesis joystick pinouts
Date: Tue, 2 Mar 93 08:10:28 CST
From: nhowland@centurion.ksu.ksu.edu (Neal Patrick Howland)
To: sysrick@starbase.spd.louisville.edu
Subject: Genesis joystick pinouts
Yes folks! It is the much requested Gensis joystick pinout information!!!
<much applause>
First some background info: The chip inside the controller is a 74HC157. This is a high-speed cmos quad 2-line to 1-line multiplexer. Basically how this works is there are two inputs ( A and B ) for every output ( Y ). There are four groups like this. There is one select signal for the whole chip. When the select signal is low, the output ( Y ) is the same as input A. When the select signal is high, the output Y is the same as input B. The pinout for the chip is as follows:
Pin 1 - Select Pin 16 - Vcc (+5V)
Pin 2 - 1A Pin 15 - G (? must be low)
Pin 3 - 1B Pin 14 - 4A
Pin 4 - 1Y Pin 13 - 4B
Pin 5 - 2A Pin 12 - 4Y
Pin 6 - 2B Pin 11 - 3A
Pin 7 - 2Y Pin 10 - 3B
Pin 8 - Gnd Pin 9 - 3Y
All the controls are done with switches. Up is a switch, Down is a switch, etc. Now, I will be refering to the output of these switches later on. What I mean is that the output is usually high, that is when the switch isn't pressed.
When the button is pushed, the output goes low. This is accomplished by connecting the output to +5V through a 10k resistor. The button is then attached between the output and ground. It looks like this:
+5V -----/\/\/------+--------- Output
10k |
|
/ |
Ground -----/ -------+
button
(normally open)
For all of those who could actually decipher the above schematic, congratulations!
I will now run down what lines from the plug are connected to what. The line numbers are determined as follows, looking straight at the plug on the front of the Genesis the numbers are:
1 2 3 4 5
6 7 8 9
(For those of you who buy a joystick cable from radio shack the pin #'s to wire colors are as follows: 1-black 2-brown 3-red 4-orange 5-get cup from bag sorry about that, lets start again 1-white 2-blue 3-green 4-brown 5-yellow 6-orange 7-red 8-black 9-gray, )
anyway, line connections:
Line 1 - Up output
Line 2 - Down output These are the only two direct connections
Line 3 - Pin 4 of the chip output 1Y
Line 4 - Pin 7 of the chip ouput 2Y
Line 5 - This line carries in +5V. It is connected to the +5V bus line.
Line 6 - Pin 9 of the chip output 3Y
line 7 - Pin 1 of the chip this carries in a select signal from the Genesis.
This is a signal which varies rapidly and controls
which input goes through the ouput
Line 8 - Ground This is connected to the Ground bus line.
Line 9 - Pin 12 of the chip output 4Y
Now for the chips pin connections:
Pin 1 - Line 7 (select)
Pin 2 - Ground (1A) don't ask me why they do this. Maybe future expansion
Pin 3 - Left (1B)
Pin 4 - Line 3 (1Y)
Pin 5 - Ground (2A) again, possibly future expansion
Pin 6 - Right (2B)
Pin 7 - Line 4 (2Y)
Pin 8 - Ground (GND)
Pin 9 - Line 6 (3Y)
Pin 10 - Button B (3B)
Pin 11 - Button A (3A)
Pin 12 - Line 9 (4Y)
Pin 13 - Button C (4B)
Pin 14 - Start (4A)
Pin 15 - Ground (G) This must be connected to ground
Pin 16 - +5V (Vcc) Power source for the chip
Anyway thats all the info needed to build your own joystick.
Now as an added bonus, additional indormation!
A simple source for a joystick cable is the Radio Shack joystick extension cable. It is around $5 and is 10 ft. long. Just snip off the connector that won't plug into the Genesis, strip the wires back, and use the color pinout list I gave above.
I went to my local arcade game repair company today and purchased the supplies I needed. They were much cheaper than I expected. Things you would need to buy from them would be:
an 8-way joystick this ran me $15
3 buttons $2.50 apei
