the EXT. port on old Genesis

I remember reading that the port is still available on later model1... On the PCB... Nothing was soldered on it...
It is an info to confirm.

 

I've only come across model 1s with the port, never without out. Know they exist but damned if I can find one.

 

Thank you very much port187 for the picture.

 

We also use to modify our Genesis consoles to add an NMI push button on the top, so we could trigger the debugger at any point. Was actually a very simple circuit.

--Selgus

 

Yes later MD1 do still have a place on the PCB for that port (marked CN4 on the PCB) but no connector... see pic: http://arcade.ym2149.com/megadrive/md1_pcb_a2.jpg

 

Excellent. I was curious what the board looked like without it. Thanks for posting that.

 

I finally got my hands on a system, unfortunately without a port or soldier points. The price was right, so I'm not complaining.

I've looked to see what information I could find out about the port, but information is scarce. I did find something of use though, some schematics [link]. According to schematic, the port itself is essentially a controller port, short a pair of resistors. The pins also directly correlate to pins on one of the chips. So with a little effort, it might not be unreasonable to add one to a newer system.

However, it seems there already is communication software written that uses the 2nd controller port [link]. That might explain why I've not been able to find much information about it. Also, I've yet to dive in to coding for the system, so I don't even know how the extra port is available on the address bus.

Anyways, I figured I'd post my findings, since I really can't find much information out there on the port.

 

Does this cable have anything to do with it?
http://www.assemblergames.com/forums/showthread.php?t=13836

 

I don't think so cause your cable have a DA-15 connector, the EXT port on the genesis is a DE-9.

 

The RAM/ROM board cable is different. It's actually a small board with a parellel connector and a DB-9 connector

 

...

I have the GEMS kit also (v2.8 BETA). In case anyone is interested, here are some (admittedly cr@p quality) photos of the GEMS RAM board and of the connector it uses to interface Genesis <-> PC.





And just for kicks, here's an equally low-quality photo of a SVP test board:

 

. Ahh, quality hardware. . I also love seeing big blobs of glue or goo on a board. That's always a sign of quality.

 

Yep, that's exactly what I have as well. I have released GEMS on my website, if anyone is interested.

 

Is there any rom on the this svp test board?

 

...

Yes, Virtua Racing.

 

I always wonder if Sega had anything else running with that chip. It does seem a bit of a waste if they only developed it for Virtual Racing.

yakumo

 

There were special versions of Daytona USA and Virtua Fighter for the SVP.

 

lol, I could hope for something else, right?

 

Ok, please explain. Since that sounds exciting