Boddah
Offline
Austin, TX

Hey guys, I decided to add a DMG Link Port to my SGB w/Internal ArduinoBoy and I'm having a little trouble.
I wired the port using this schematic,

The CPU pins 68, 69, & 70 are connected to both the link port and the ArduinoBoy, the same with GB pins 1 and 32. CPU pin 63 only goes to the link port.
The ArduinoBoy has no problems communicating with the CPU, but nothing seems to be going to the link port. Could this be caused by the 220 ohm resistors on the link port? I tried syncing the SGB with a DMG both running LSDJ to see if it could do the simple Master/Slave sync, but nothing happened. Also, I could only get my EMS USB cart to boot, my Non-usb smart card would not boot for some reason. Before installing the link port I didn't have trouble getting it to boot, but it could just be dirty pins/connectors.

Any suggestions?

Jazzmarazz
Offline
Michigan

Ask Doug. I drew that image for him and he never really helped me get my own to work!
http://consolemods.freeforums.org/post477.html#p477

Timbob
Offline

While using just resistors might work, it's not ideal.

A method like this copies the original gameboy schematic, giving more stable and saver results:
http://www.devrs.com/gb/files/sgbmod.txt

You do need some more parts tho, but I made a few like that, and they work like a charm smile

nitro2k01
Offline
Sweeeeeeden

You've probably connected it in parallel with the link port, and the Arduinoboy will completely drown out the signal that's coming in from the link port. My quick and dirty fix to this problem is to add two diodes between the link port and the Arduinoboy. These should be switching diodes like the good old 1N4148, not LEDs!

Unless I've made a mistake in my thinking, this is what you need to do. Keep the resistors where they are. Connect pin 5 through a diode to Arduino analog 0. Connect pin 3 through a diode to Arduino analog 1. (As before but through a diode in both cases.) The should have it's cathode connected to the Arduino in both cases. Ie, the diode should "point to" the Arduino. This should make it possible to use either the link port or the internal Arduinoboy, but take care to not use both simultaneously, which will fail.

Re: Timbob. Those extra components are there to protect the CPU and to meet RF emission regulation, but they won't actually do very much to the signal. And their absence is certainly not the problem in this case.

thursdaycustoms
Offline
Cleveland, OH

I still haven't decided if I want to release this yet. Basically a link port kit for SGB:

The link port itself should have a diode on pin 1.

Maybe this little image will help clear some things up as well:

herr_prof
Offline
Unsubscribe

release it!

katsumbhong
Offline
Taichung, Taiwan

This is exciting.

kitsch
Offline
matt's mind
herr_prof wrote:

release it!

yes, do as he says

kineticturtle
Offline
Matthew Joseph Payne
kitsch wrote:
herr_prof wrote:

release it!

yes, do as he says

Yes, do as they says.

Timbob
Offline
nitro2k01 wrote:

Re: Timbob. Those extra components are there to protect the CPU and to meet RF emission regulation, but they won't actually do very much to the signal. And their absence is certainly not the problem in this case.

Ah! I learned today.

thursdaycustoms
Offline
Cleveland, OH

Haha alright guys. I was going to try to buy a bunch of broken Game Boys and harvest the link ports so I could sell them assembled. I'll have to just do the PCB with components and you can supply your own link port.

Jazzmarazz
Offline
Michigan

Sounds like a plan.

TylerBarnes
Offline
Dallas, Texas
thursdaycustoms wrote:

Haha alright guys. I was going to try to buy a bunch of broken Game Boys and harvest the link ports so I could sell them assembled. I'll have to just do the PCB with components and you can supply your own link port.


You could buy dmg-07's get three link ports plus a cable with 5v pin on it for your arduinoboys. They are way cheaper, Rock30games sells them for $1 each. Just a thought.

Last edited by TylerBarnes (Sep 14, 2013 4:04 am)

thursdaycustoms
Offline
Cleveland, OH

That's a pretty good idea actually.

Last edited by thursdaycustoms (Sep 14, 2013 5:45 am)

Boddah
Offline
Austin, TX

thursdaycustoms -  I've been waiting for you to release those suckers for a long time, they would work great with SGB's and they look really nice. I agree with TylerBarnes about buying a ton of 4-player adapters and scrapping the 3 ports, and you could use the cable for your ArduinoBoys. I recently bought a ton of those and I'm using the cables in my DIY AB kits, and the port on my SGB is from a 4-player adapter. I'd be willing to trade some of the PCBs with the link ports still attached for one of those fancy SGB link port kits smile

thursdaycustoms
Offline
Cleveland, OH

That trade could happen! I cleared out their stock on 4-way players last night though wink