Adding a Link Port to Super Gameboy - Revision history

Mantidactyle: /* The Idea */ archive.org link

2016-08-17T00:30:31Z

‎The Idea: archive.org link

Nitro2k01: /* Schematic */

2008-03-10T01:33:50Z

‎Schematic

Nitro2k01: /* Schematic */

2008-03-10T01:33:38Z

‎Schematic

Nitro2k01: /* Adding a Link Port to Super Gameboy - Joshua Neal (V.1 10/16/1999) */

2008-03-10T01:23:33Z

‎Adding a Link Port to Super Gameboy - Joshua Neal (V.1 10/16/1999)

Nitro2k01: /* Adding a Link Port to Super Gameboy - Joshua Neal (V.1 10/16/1999) */

2008-03-10T01:23:19Z

‎Adding a Link Port to Super Gameboy - Joshua Neal (V.1 10/16/1999)

Nitro2k01: /* Schematic */

2008-03-10T01:22:56Z

‎Schematic

Nitro2k01: New page: = Adding a Link Port to Super Gameboy - Joshua Neal (V.1 10/16/1999) = Warning: This is the documentation of the my own project. There is the potential to damage your hardware, so if you...

2008-03-10T01:21:53Z

New page: = Adding a Link Port to Super Gameboy - Joshua Neal (V.1 10/16/1999) = Warning: This is the documentation of the my own project. There is the potential to damage your hardware, so if you...

New page

= Adding a Link Port to Super Gameboy - Joshua Neal (V.1 10/16/1999) =

Warning: This is the documentation of the my own project. There is the
potential to damage your hardware, so if you attempt to do this, know what
you are doing before attempting this. I specifically disclaim any
responsibility for injury or damages caused.

== The Idea ==

The idea came from a web page in Japanese, so the original credit goes to
the authors of that page, Papa and Shaora, as they are the ones who figured
out that it would work. That page is at the following URL, you may want to
check it out for the pictures:

http://www.bomber.co.jp/chaola/labo/SGB_comm/ (Dead link, editor's note)

== Theory ==

Basically the SGB-CPU in the Super Gameboy is the same as the one in the
gameboy itself, including the pinout. This means that the hardware for
link port communications exists, it just isn't connected to anything.
Nintendo makes a Super Gameboy 2 for the famicon that has the link port.
This would have cost me a bunch of $$$, so I chose to try to add one to my
original SGB.

== Inside the SGB ==

The first task was opening the Super Gameboy. This required a special tool
that I don't have. After attempting futiley to remove them without that
tool, I took the game to a local used game store and asked them to open it
for me. They thought it was strange, but they did it anyways...

Comparing the circuit board inside with the pictures on the japanese page, I
determined that the circuit board of the Famicon version of the SGB was
identical to the Super Nintendo version. I located the three pins on the
circuit board that would have to be soldered to, on the chip marked SGB-CPU.

These pins were really tiny, so I decided I needed some soldering practice.
I found a non-working PC device with a chip that had the same pin spacing,
and practiced soldering leads to that until I felt confident enough to do it
on the SGB.

I found it worked best if I scraped the pin with a knife to remove any
coating, put a small bit of solder on the pin, then prepare the wire and
reflow the solder on the pin and stick the wire on.

== Schematic ==

The schematic on the Japanese page used only a resistor for each data line,
comparing Jeff Frohwein's GB and SGB schematics, it looked like an
additional pair of diodes and a capacitor for each data line would provide
the same protection and noise filtering as the gameboy. I decided to include
these in my project. The schematics are located at:

http://home.hiwaay.net/~jfrohwei/gameboy/gameboy1.gif -- [[DMG_Schematic|Gameboy Schematic]]
http://home.hiwaay.net/~jfrohwei/gameboy/sgb.gif -- [[SGB Schematic]]

== Parts ==

*7 germanium diodes
*3 100 picofarad ceramic capacitors
*3 220 ohm resistors
*spool 30ga wire-wrap wire
*1 gameboy link port connector (female)

I used wire-wrap wire to make all the connections, only with solder joints
instead of wire wrapping.

The japanese page shows using a link cable cut in half for the connector,
while I had one of these lying around, I used a female port from an adapter
that came with a link cable that would allow it to connect to a classic
gameboy with the larger link port size. This was inside a nice black
connector shell, that was held together with a small screw. Once opened,
it turned out to be possible to cut the larger connector off and have a nice
female port that would accomodate a standard link cable.

I used this connector in my project, also using the black shell, which I
epoxied inside the SGB after cutting a matching hole in the side, leaving
it such that I could still unscrew and open the connector shell. This made
the connector sturdy, and look somewhat attractive as well.

== Schematic ==

I soldered together a point-to-point circuit for this, roughly in the shape
of the following diagram. It might have also been possible to make a small
circuit board that fits inside the SGB. With this circuit, operation should
be identical to that of the gameboy.

Key:
-|<- germanium diode
-)|- 100pF ceramic capacitor
-/\/\/- 220 ohm resistor

VCC ----+--------------------+-------------------+---->|----- to link pin1
| | |
+-|<-+--o to +-|<-+--o +-|<-+--o
SGB | SGB + SGB +
pin o-/\/\/-+ to pin o-/\/\/-+ to pin o-/\/\/-+ to
68 | link 69 | link 70 | link
+-)|-+ pin5 +-)|-+ pin3 +-)|-+ pin2
| | | | | |
+->|-+ +->|-+ +->|-+
| | |
GND ----+--------------------+-------------------+----------- to link pin6

Link Port Pins (looking at external female connector)
_____
/ \
|5 3 1|
|6 4 2|
+-----+

The VCC lead I soldered to a plated-thru hole in the SGB circuit board
near the 5v pins (27 and 58) of the snes connector. The ground lead I
soldered to a plated-thru hole in the large ground plane area.

== Assembly ==

Once I got this circuit built and connected to all the necessary pins, I
hotglued down anything that might shift around, cleaned up my soldering
mess with flux remover, and put the SGB back together, only using screws
with phillips heads instead of the original screws.

== Testing ==

I made several picture transfers with a gameboy camera, and tested operation
of the printer, all of which worked. I deemed the project a success!

- Joshua Neal <tinara@goodnet.com>

@@ Line 1: / Line 1: @@
 = Adding a Link Port to Super Gameboy - Joshua Neal (V.1 10/16/1999) =
-''' Warning: This is the documentation of the my own project.  There is the
+''' Warning: This is the documentation of the my own project.  There is the potential to damage your hardware, so if you attempt to do this, know what you are doing before attempting this.  I specifically disclaim any responsibility for injury or damages caused. '''
 potential to damage your hardware, so if you attempt to do this, know what
 you are doing before attempting this.  I specifically disclaim any
 responsibility for injury or damages caused. '''

@@ Line 11: / Line 11: @@
 check it out for the pictures:
-http://www.bomber.co.jp/chaola/labo/SGB_comm/ (Dead link, editor's note)
+[https://web.archive.org/web/20021027084502/http://www.bomber.co.jp/chaola/labo/SGB_comm/ SGB Communication Cable Assembly]
 == Theory ==

@@ Line 85: / Line 85: @@
 be identical to that of the gameboy.
-Key:
+ Key:
   -|<-    germanium diode
   -)|-    100pF ceramic capacitor

@@ Line 89: / Line 89: @@
   -)|-    100pF ceramic capacitor
   -/\/\/- 220 ohm resistor
-−
-−
   VCC ----+--------------------+-------------------+---->|----- to link pin1
           |                    |                   |

@@ Line 54: / Line 54: @@
 these in my project.  The schematics are located at:
-http://home.hiwaay.net/~jfrohwei/gameboy/gameboy1.gif  -- [[DMG_Schematic|Gameboy Schematic]]
+http://home.hiwaay.net/~jfrohwei/gameboy/gameboy1.gif  -- [[DMG_Schematics|Gameboy Schematic]]<br />
 http://home.hiwaay.net/~jfrohwei/gameboy/sgb.gif       -- [[SGB Schematic]]